Hull Speed Calculator
Table of contents
Welcome to the hull speed calculator . If you've ever seen a boat go so fast that its nose started rising, then you've seen the concept of hull speed in action. In this article, we'll explain what hull speed is and what it means for a ship's design. Later, we'll show you how to calculate hull speed with the hull speed formula, so that you can work out how to calculate hull speed for your own boat.
What is hull speed?
Hull speed is the speed at which a vessel with a displacement hull must travel for its waterline to be equal to its bow wave's wavelength. A displacement hull travels through water, instead of on top of it as a planing hull (like a kiteboard ) would, thereby displacing water with its buoyancy as it sails. The pressure that this displacement exerts on the water creates a wave; this wave is known as the vessel's bow wave . A slow-moving boat's bow wave might make small waves, but, as the boat sails faster, the bow wave's wavelength λ \lambda λ grows. When the wavelength meets the waterline length (that's also when the bow wave's first and second crests are at opposite tips of the waterline), the boat is said to be traveling at hull speed. Take a look at the picture below to see what we mean:
Why does hull speed matter?
Although it's not perfect, hull speed remains a useful concept that can help us answer questions about how fast a sailboat can go, and the optimal amount of thrust you need to keep a boat moving forward.
A boat's hull speed limits how fast it can travel efficiently. When traveling at hull speed, the boat's bow wave and stern wave have synchronized and constructive interference occurs, which allows the boat to move very efficiently. However, at speeds greater than hull speed, a vessel's nose automatically starts rising as the vessel tries to climb its bow wave. This process is called planing , and it wastes lots of energy. Trying to move faster than the hull speed will therefore require more and more thrust (whether that comes from sails, rowing, or engines) in exchange for smaller and smaller gains in speed as more energy is wasted angling the boat upwards. Hull speed can therefore be said to impose a flat limit on how fast a sailboat can go.
Shortcomings of hull speed
Although the physics behind hull speed is sound, it is heavily dependent on the hull's shape. Long and thin hulls with piercing designs can easily break their hull speed without planing. Such hulls are found on:
- Catamarans; and
- Competitive kayaks.
A hull's design can enable it to circumvent the workings of hull speed. It is for this reason that hull speed is not used in present-day ship design; naval institutions nowadays favor more modern measurements of speed-to-length ratio, such as the Froude number .
How to calculate hull speed
The formula for hull speed only needs the length of the vessel's waterline in feet, denoted as L waterline L_\text{waterline} L waterline . With this length, the vessel's hull speed in knots can be calculated with
If you want to instead work out exactly how long your new boat's waterline must be for it to have a certain hull speed, you can invert the formula to obtain
How to use the hull speed calculator
The hull speed calculator is just as easy to use as the formula.
Enter your vessel's waterline length into the first field. This is the length of your boat's hull at the height of the waterline. Your vessel's hull speed will then be calculated and presented in the second field.
You can also use the hull speed calculator backward to work out how long a vessel's waterline must be if you know its hull speed.
You can freely change the units of your measurements without interfering with the hull speed formula.
How can I increase my boat's hull speed without changing its hull?
Load your boat heavier! If you think about a normal displacement hull, it's usually narrower near the bottom than at the deck. So pushing it down with some weight will lengthen the boat's waterline, and so its hull speed is increased. Of course, heavier boats are harder to move, so while your loaded boat now has a higher hull speed, you would need more power to move it.
Waterline length
The length of the ship at its waterline.
The speed at which the ship's waterline length equals its bow wave's wavelength.
Catamaran Hull Speed Calculator
What is the formula for the hull speed of a catamaran?
The formula for the hull speed of a catamaran is the same as the formula for the hull speed of any displacement hull:
Hull Speed (in knots) = 1.34 * √(Waterline Length in feet)
How do you calculate the hull speed of a boat?
To calculate the hull speed of a boat, you can use the formula:
What is the hull speed of a boat with a 16-foot waterline?
The hull speed of a boat with a 16-foot waterline is approximately 4.8 knots.
How much faster is a catamaran than a monohull?
The speed difference between a catamaran and a monohull can vary depending on various factors such as design, size, and conditions. In general, catamarans are known for their higher speed potential, and they can be significantly faster than monohulls, especially in certain wind conditions.
What is the average speed of a 40 ft catamaran?
The average speed of a 40-foot catamaran can vary depending on factors such as design, weight, wind conditions, and sail configuration. In general, a 40-foot catamaran can sail at speeds ranging from 7 to 12 knots or more.
How much horsepower is required for hull speed?
The amount of horsepower required to reach hull speed depends on the boat’s design, weight, and hull efficiency. For displacement hulls, it is challenging to significantly exceed hull speed with additional horsepower.
What happens if you exceed hull speed?
Exceeding hull speed on a displacement hull creates a significant increase in wave resistance and drag, making it challenging to achieve higher speeds. The boat may experience a substantial bow wave, and excessive engine power will not yield a proportional increase in speed.
What is the hull speed of a 12-foot boat?
The hull speed of a 12-foot boat is approximately 3.3 knots.
What is the formula for boat speed?
Boat speed can be calculated using a variety of factors, including the boat’s hull design, sail configuration, wind speed, and current. There isn’t a single formula for boat speed, as it can vary based on different parameters.
What is the best hull for speed?
There is no one-size-fits-all answer to the best hull for speed, as it depends on the type of boat and intended use. However, hull designs with low drag, such as planing hulls and hydrofoil hulls, are known for their high-speed capabilities.
Does a dirty hull slow a boat?
Yes, a dirty hull can create more drag and resistance, slowing down a boat’s speed. Fouling, such as algae and barnacles, can significantly affect a boat’s performance.
How does waterline length affect speed?
Waterline length directly affects a boat’s hull speed. Longer waterline lengths generally result in higher hull speeds, as per the hull speed formula.
What is the disadvantage of catamarans?
Some potential disadvantages of catamarans include higher initial costs, limited marina spaces for wide beams, and greater windage in strong winds. Additionally, some sailors may find monohulls to be more traditional and aesthetically pleasing.
Can catamarans handle rough seas?
Yes, catamarans can handle rough seas, and they are generally more stable than monohulls in such conditions. However, like any vessel, proper seamanship and handling are essential for safe navigation in rough seas.
Why are catamarans good in rough water?
Catamarans are good in rough water due to their wider beam, which provides increased stability compared to monohulls. Their twin hulls also reduce rolling and improve comfort in rough seas.
Can you sail a 40-foot catamaran by yourself?
Sailing a 40-foot catamaran alone can be challenging and may require advanced sailing skills and experience. Many 40-foot catamarans are designed for two-person handling or more.
Are longer catamarans faster?
Longer catamarans often have the potential for higher speeds, but performance depends on factors such as design, weight, sail configuration, and wind conditions.
Is a catamaran faster than a sailboat?
In general, catamarans are known for their higher speed potential compared to monohull sailboats, especially in certain wind conditions. However, specific performance varies depending on the design and size of the boat.
How fast is 350 horsepower for a boat?
The speed of a boat with 350 horsepower depends on the boat’s design, size, and hull efficiency. Boats with 350 horsepower can reach speeds in the range of 40 to 60 mph or more.
What makes a boat hull fast?
A fast boat hull typically has low drag, smooth lines, and efficient hydrodynamics. Planing hulls and hydrofoil hulls are designed for high-speed performance.
How much horsepower is required to go 60 mph?
The horsepower required to reach 60 mph depends on the boat’s size, weight, and hull design. Boats with high-powered engines in the range of 300 to 600+ horsepower are commonly capable of reaching such speeds.
What is the fastest boat hull shape?
The fastest boat hull shapes are typically planing hulls, which are designed to rise out of the water at high speeds, reducing drag.
Can you sail faster than hull speed?
Displacement hulls cannot typically exceed hull speed, but planing hulls and some high-performance boats can sail faster than their hull speed.
Why do longer sailboats go faster?
Longer sailboats often have longer waterlines, which increases their potential hull speed and allows them to achieve higher speeds.
What is the hull speed of a Harbor 20?
The Harbor 20 is a 20-foot sailboat, so its approximate hull speed can be calculated using the general formula:
What is the speed of the boat in still water if it takes 12 hours to cover 64 km downstream and 8 hours to cover 32 km upstream?
The speed of the boat in still water can be calculated using the formula:
Boat Speed (in km/h) = (Downstream Speed + Upstream Speed) / 2
Downstream Speed (in km/h) = Distance downstream / Time downstream
Upstream Speed (in km/h) = Distance upstream / Time upstream
What is considered slow speed on a boat?
Slow speed on a boat is typically relative and can vary depending on the type of boat and water conditions. In general, a slow speed might be considered anything below 5 knots.
What is the speed of the boat per hour?
The speed of the boat per hour depends on the boat’s hull design, engine power, and conditions. It can range from a few knots for slower vessels to 30 knots or more for high-speed boats.
How fast is a semi-displacement hull?
A semi-displacement hull is designed for speeds between that of a displacement hull and a planing hull. It can typically reach speeds up to 15 to 20 knots.
What is the max speed of my boat?
The maximum speed of a boat depends on its design, engine power, and weight. Manufacturers often provide a maximum speed rating, but it’s essential to consider safety and operating conditions.
What is the best hull for choppy water?
A deep V-hull is often considered one of the best hull designs for handling choppy water. It helps to cut through waves and provide a smoother ride.
What is the most durable hull material?
Fiberglass is a common and durable hull material for many boats. It offers strength, longevity, and resistance to corrosion and degradation.
What boat hull is most stable?
Catamarans are known for their stability due to their twin hulls, which offer excellent stability both at rest and underway.
What is the beam length ratio for a catamaran?
The beam length ratio for a catamaran is typically expressed as the beam (width) of the catamaran in relation to its length. Catamarans generally have a beam-to-length ratio of 1:1 or more.
What makes a boat travel faster in the water?
A boat can travel faster in the water by reducing drag, optimizing the hull design, and increasing engine power.
Do longer boats ride better?
Longer boats often provide a smoother and more comfortable ride due to their longer waterline length, which helps them glide over waves more easily.
What is the longest-lasting hull material?
Fiberglass is known for its longevity and durability, making it one of the longest-lasting hull materials.
How often do you need to wax a boat hull?
The frequency of waxing a boat hull depends on factors such as the hull material, environmental conditions, and usage. In general, boat owners may choose to wax their hulls once or twice a season.
Do boats go faster in shallow water?
Boats may experience increased speed in shallow water due to the ground effect, but this can also be dangerous as the boat’s propeller and hull may be at risk of damage.
Why are catamarans not popular?
Catamarans are popular in certain sailing communities, but they may be less common in some regions due to higher initial costs and limited marina spaces for wide beams.
What is the best size catamaran to live on?
The best size catamaran to live on depends on individual preferences and living requirements. Many liveaboard catamarans range from 40 to 50 feet in length.
Why can’t catamarans sail upwind?
Catamarans can sail upwind, but their ability to do so efficiently may be limited compared to monohulls. Some catamarans have daggerboards or centerboards that improve upwind performance.
Do catamarans tip over easily?
Catamarans are known for their stability and resistance to tipping over. They are less likely to capsize than monohulls.
How easy is it to capsize a catamaran?
Capsizing a catamaran typically requires extreme conditions and mishandling. When sailed and handled properly, catamarans are very stable and resistant to capsizing.
Can catamarans tip over?
Catamarans can tip over, but this is less likely to happen compared to monohulls due to their wider beam and stability.
How big of a wave can a catamaran handle?
The wave height that a catamaran can handle depends on its design and size. In general, most modern cruising catamarans are designed to handle waves of 10 to 20 feet or more.
What is the most stable boat in rough water?
Catamarans are considered among the most stable boats in rough water due to their twin hulls and wide beam.
Are catamarans wobbly?
Catamarans can experience some wobbling or rocking motion, particularly when anchored or in certain sea conditions, but they are generally more stable underway compared to monohulls.
Do catamarans hold their value?
Catamarans often hold their value well in the used boat market due to their popularity and demand.
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- PERFORMANCE TOPICS
Optimising Hull Lines for Performance
This article was inspired by a question about the rocker line in the new 8.5m cat Design 256 and I want to stick to the point, so we won’t turn it into a book, but I’ll discuss two issues, hull fineness ratio and some aspects of the rocker profile.
When you manipulate the hull form you’re adjusting the lines in three planes, waterplanes (plan view), buttocks (side view including the keel rocker) and the section shapes. So you need to be aware of how the shapes are changing in the other two planes as you manipulate any one of these three, or all three globally as is now possible with computer modelling.
There are two fundamental constants that you start with and don’t change throughout the process. The big one is the displacement or the amount of buoyancy you need.
If you make the hull finer by narrowing the waterlines you have to increase the draft or make the ends fuller to get back to the required displacement number.
If you flatten the rocker line you have to increase the hull width, fill out the ends, or square up the section shapes rather than having a V or rounded V.
The other constant is the longitudinal centre of buoyancy. You really can’t do any meaningful shaping of the hull form until you have settled on the these two constants.
A third number that we can plug in as a constant if we want to is the prismatic coefficient which describes bow much volume there is end the ends relative to the cross section shape in the middle of the boat, but in sailing boats this is of less importance compared to other factors.
The hull lines for Design 256, 8.5m Cat. It's that hump in the rocker line - right under the back of the cabin that brought up the question and is one of the key points discussed here.
Hull fineness.
Fine hulls are fast, but only in the higher speed range. There’s a misconception I come across quite a bit that you can add weight and windage and you’ll still be fast as long as your hulls are fine.
Well you won’t be. Your boat will simply sink to find the new state of equilibrium. If your transoms are submerged you’ll have more drag. If your bridge deck is too close to the water you’ll have slamming. Much better to be conservative with your displacement figure in the design stage than overly optimistic.
And fine hulls have more wetted area so you have more drag in light air where friction resistance is the primary drag factor.
I’ve seen promotional material for catamarans stating that the boat has less wetted area because it has fine hulls. For a given displacement the minimum wetted area is described by a sphere (or a semi sphere in the case of a floating object). The more you stretch it out in length, keeping the displacement constant, the more wetted area you have.
The more you make the section shape into a deep V or a broad U with tight corners, as opposed to a semicircle, the more wetted area you have. Add into the equation finer hulls are slower to tack.
So fine hulls are only an advantage if your boat is light and has enough sail area to ensure you’re travelling at speeds where form resistance is greater than skin resistance.
In my view the advantage of fine hulls is often overrated as it applies to cruising cats.
At the other end of the scale the resistance curve is fairly flat up to about 1:9 which is still quite fast in most conditions. From there the resistance rises steeply as the hull gets fatter and at 1:8 and fatter you’re suffering from some serious form drag.
This is the rocker line isolated from the lines plan above (in blue) and and the red line shows a more moderate rocker line that achieves the same buoyancy and maintains the centre of buoyancy in the same position. The bow is to the right.
In the image lower right I've squashed it up and increased the height to make the difference in the lines more obvious.
The difference in the two lines is quite subtle, but races are often won or lost by seconds.
Rocker Profile
So if we’re looking for low wetted area we would want a rocker profile that was even and rounded, relatively deep in the middle and rising smoothly to the surface at each end. But this would give us a low prismatic which is not ideal in the higher speed range, and it’s not ideal for pitch damping which in my view is the critical design factor that is often underrated.
Pitching is slow. It destroys the airflow in your sails and the flow around the hulls, and your performance is suffering from slamming loads.
The single most effective way to counter pitching is with asymmetry in the water planes. You can achieve that in the with a fine bow and broad transom. Or you can achieve it with V sections forward and a flattened U shape aft. Or you can achieve it in the profile view with a very straight run forward and a bump in the aft sections. A flatter rocker line is better for resisting pitching than an evenly curved one with deeper draft in the middle.
The final result is a combination of all three of these factors.
On a cat like Design 256 the weight is concentrated well aft so we need to get buoyancy well aft.
The kink you see in the rocker profile helps to do this. It also helps to keep the rocker straight for most of its length and smooth the water flow exiting the hull aft at higher speeds, possibly promoting some planing effect.
If we had a more even rocker line we would slightly reduce the wetted area, but we would increase the pitching and the water would exit the hull aft at a steeper angle, increasing form drag in the higher speed range.
How much of a bump can you put in there without creating a flow separation, and how damaging would that flow separation be? I really don’t know. The way all of these factors interplay in the various conditions we sail in is very complex.
Ultimately a lot of this work is gut feel nurtured by experience, observing things in nature and most importantly experimenting and trying new ideas.
Is the new Groupama AC45 a breakthrough that will influence the form of racing catamarans into the future? I don’t think anyone has a computer that can answer that. We have to wait and see.
Symmetric and non symmetric water-planes. The blue line with grey fill is the DWL from the design above. As is typical with modern cat hulls the bow is long and fine, the stern is full and rounded. This is the asymmetry that has a damping effect on pitching. The red line on the other hand is more like you would see on a double ended monohull and quite a few multihulls have also used this shape in the past. It's quite symmetric about the pitch axis and does not have good pitch resistance.
The hull lines of the new 8.5m Sports Cat Design 256
Mad Max , Previously Carbon Copy . She was designed in 1997 but she's the current (2016) title holder of the Australian Multihull Chamionships (2 successive years) and the fastest inshore racing boat in Australian waters.
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CRUNCHING NUMBERS: A Better Way to Estimate Hull Speed
It’s been a while since we discussed all those mysterious numbers that both boat designers and journalists are always throwing around to confuse us when they talk about boats. You’ll recall last time I bloviated about displacement/length ratios . One big reason it’s a good idea to go to the trouble to calculate a boat’s D/L ratio is that you can use this number to refine your estimate of the boat’s maximum speed potential beyond the relatively rough estimate afforded by the classic hull-speed formula we discussed earlier.
This more accurate method of finding a boat’s potential top speed, devised by designer Dave Gerr and published in his tome, The Propeller Handbook , can also be used to estimate the hull speeds of multihulls (both catamarans and trimarans). Dave warns, however, that catamarans with very narrow hulls (for mysterious reasons that no one really understands) will often exceed the speeds predicted by his method.
To comprehend Dave’s formula, we first need to comprehend that the famous multiplier we used in the classic hull-speed formula (1.34) is in fact what is known as a speed/length ratio (S/L ratio). This ratio quantifies the relationship between a boat’s speed (BS), whatever it happens to be at any given point in time, and its waterline length, according to a formula that holds that S/L ratio equals a boat’s speed in knots divided by the square root of the boat’s load waterline length (S/L ratio = BS ÷ √LWL).
The brightest kids in class will instantly note that this is simply the classic hull-speed formula (HS = 1.34 x √LWL) run backwards to solve for the speed/length ratio instead of speed. What the classic hull-speed formula assumes is that 1.34 is the maximum S/L ratio that can ever be achieved (due to the characteristics of waves we discussed before) and thus always serves to limit a boat’s top speed potential.
What Dave’s formula does is estimate a boat’s maximum S/L ratio based on its D/L ratio so as to more accurately reflect the fact that lightweight boats are more capable of exceeding their nominal hull speed. Once we’ve arrived at a new and more accurate S/L ratio for a given boat, we can then plug it into the classic hull-speed formula to derive a new, more accurate estimate of that boat’s nominal hull speed.
Dave’s formula holds that a boat’s maximum S/L ratio equals 8.26 divided by its D/L ratio to the .311 power (Max S/L ratio = 8.26 ÷ D/L ratio↑.311). For a 12,000-pound boat with a 28-foot waterline and a D/L ratio of 244, we thus get the following results: 244 to the .311 power equals 5.53 (you’ll obviously need a scientific calculator to figure that out!), therefore 8.26 ÷ 5.53 equals a maximum S/L ratio of 1.49. Plug 1.49 into the hull-speed formula (1.49 x √LWL) and you get a new nominal hull speed of 7.9 knots (1.49 x 5.29 = 7.88), as compared to the boat’s old nominal hull speed of 7 knots (1.34 x 5.29 = 7.08).
This in itself is an appreciable difference, but it grows even larger as the boat grows lighter. Assume, for example, that our 12,000-pound boat has shed 3,000 pounds to become a 9,000-pound boat with the same load waterline length, and its D/L ratio drops to 183. Its old nominal hull speed, based solely on its LWL, remains exactly the same at 7 knots, but its new nominal hull speed, figured according to Dave’s method, now becomes 8.6 knots!
Things get even more exciting if you bear in mind that this revised hull-speed estimate still does not account for a boat’s potential to plane. That is, we’re still only talking about the top potential speed that may be achieved by a hull in displacement mode. Dave further warns that getting the extra hull speed his method predicts will require a lot of extra power, but he does maintain that his method is ultimately more accurate than the old one.
I, for one, happen to believe him. Running Dave’s formula on your own boat and finding out that its top speed is higher than you thought is an easy way to put a smile on your face. Unless you own a classic CCA-style cruiser with long overhangs. These boats have exaggerated D/L ratios, due to their short static waterlines (which get longer when the boat starts sailing and heels over) and when you run Dave’s formula on them you usually get a lower top speed. In cases like this, I always assume the classic hull-speed formula is more accurate.
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I love your blog
Thank you for this information it’s kind of you to share it.
This may be a reasonable estimate for BOATS, but it is not scalable to larger SHIPS. Let me give you an examples. — The Iowa Class Battleship has a displacement of 50,000 long tons and a length of 860 ft. This gives a D/L ratio of 78.6 and a S/L ratio of 2.12. This then indicates that Hull Speed = 2.12 x Sqrt (860) = 62.17 knots. We know that is bullshit because the Iowa has 212,000 shp for it’s 50,000 tons or greater than 4 shp per ton. We also know that it is a 33~35 knots ship depending on load (and hence draft). There is no way her hull speed is 62 knots. — The Queen Mary 2 cruise ship is about 87,000 tons and 1132 ft long. This gives a D/L ratio of 136.8 and a S/L ratio of 1.79. THis then indicates that the Hull Speed = 1.78 x Sqrt (1132) = 59.9 knots. The QM2 has 115,300 shp delivered via her four mermaid pods or about 1.33 shp per ton. In service she is a 28 knots vessel which reached 30 knots during her trials. Again, there is no way her Hull Speed is 60 knots.
Great article but I have a question. How can this be applied to displacement hulls? Specifically to kayaks or surfskis. Does the constants and formulas hold true for this kind of vessels?
I have an Epic v7 surfski which measures 17′ long and weighs 53 lbs. According to the standard hull speed calculations, it has a theoretical hull speed of 5.52 knots. However, if I try to use these formulas, the Boat Speed comes to 20.89 knots. Its creator, an olympic medallist, is able to push it to 7.18 Knots for long distances which could very probably translate to a slightly higher speed for shorter distances; but no one on muscle power alone could drive it to 20 knots or even close to that.
Something clearly needs to be adjusted for it to apply to small displacement hulls.
Did you factor in the rower’s weight? I get 12.9 kts with a 150 pound rower.
Interesting. I am currently boatless and looking at purchasing something in the 30′ range (sail) and comparing potential hull speeds. One boat has a 24 ft waterline and the other 25. I assumed the longer wl would give me a bit more speed as the old formula shows. However the longer WL boat also displaces 1,400 lbs more so by this new formula the shorter boat has the same theoretical hull speed. Good to know. Thanks!
The math shown in the example doesn’t work. 12000/28=428.57 not 244. Raise that to the power of .311 and you get 6.585. 8.26/6.585=1.254
Mark: you need to scroll up and click on the previous article on D/L ratios; (in red) The exact number works out to 243.6, rounded to 244.
Did I miss something, or does David’s sailboat speed-prediction formula ignore sail-area. ,,,& is based only on D/L & boat-length?
So then, is Dave saying that sail-area is irrelevant to a sailboat’s speed?
Hi Michael! Thanks for the comment. The answer is yes, Dave’s formula ignores sail area and treats only the maximum speed potential of any given hull. But no, sail area is obviously not irrelevant. Dave’s formula, like the traditional speed-prediction formula it replaces, merely assumes a sailplan powerful enough to drive the boat at its maximum speed.
I ran into this formula in your book The Modern Cruising Sailboat. Running the numbers for our 31ft double ender gave pretty interesting results:
Traditional hull speed: 6.8kt Gerr’s hull speed (light ship): 7.1kt Gerr’s hull speed (2t load): 6.4kt
Now, there are no polars (or much other performance material) available on our boat, so I’ve constructed polars based on the actual recorded wind speeds and angles vs. actual sailing speeds during last two summers of cruising. And you know what is the top speeds I get there? 6.4kt! Coincidence? Probably not.
I always find these exercises interesting. And probably very worth while to designers, as an end user the only thing that matters is real world sailing characteristics. To reflect on theoretical speed potential of my boat, which has over 700 sisters and an established racing record would just be frustrating. When shopping for a new boat I would look at established history and PERF ratings. They are a long term average of a particular hull form and should predict what the sailor can expect. Theory is would only come into my calculations if I were comissioning a new design, but once she is built the proof is in the boat.
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Catamaran Hull Design
- Post author By Rick
- Post date June 29, 2010
- 2 Comments on Catamaran Hull Design
Part 1: Notes from Richard Woods
Since the America’s Cup experimented with going multihull, there’s been a lot of interest in catamaran performance and the catamaran hull designs that define performance. Many guys are investigating whether to buy a catamaran or design and build their dream boat. Let it be said here that building a large catamaran is not for the faint of heart. People begin building 100s of boats a year, yet few are ever completed, as life always seems to have a way of interfering with a good boat build.
Never the less, since the rest of this website is about selecting and buying a boat , it only seems fair to have at least one webpage that covers catamaran design. This page contains notes on boat hull design goals and an accompanying page from Terho Halme has mathematical formulas used in actual catamaran hull design. It has become a popular research stop and an important reference to the catamaran design community.
The content of this page was reproduced from the maestro of Catamaran designs, renown British naval architect, Richard Woods, who not only designs catamarans, he sails them across oceans…. repeatedly. He has a lot to say on the subject of catamaran hull design.
“…When it’ all said and done, the performance of a sailing catamaran is dependent on three primary specs: length, sail area and weight. If the boat is longer it generally means it’ a faster boat. If she has more sail area, it means she’ a faster boat and if she’ light it means she’ a faster boat. Of course, there are limits: Too much sail area capsizes the boat in brisk winds. If the boat is designed too light, she will not take any kind of punishment. Too slim a hull design and the boat becomes a large Hobie Cat capable of only carrying your lunch. Of course, too long and large and you’d have to be Bill Gates to afford one. Then there are lot of additional and very important factors like underwater hull shape, aspect ratios of boards and sails, wet deck clearance, rotating or fixed rigging and so on….” Richard Woods
All Catamarans are not equal, but all sailboats have two things in common: They travel on water and they’re wind powered, so the Catamaran design equations in the 2nd part should apply to every catamaran from a heavy cruising Cat to a true ocean racer.
Richard Wood’s comments on catamaran design:
We all know that multihulls can be made faster by making them longer or lighter or by adding more sail. Those factors are the most important and why they are used as the basis of most rating rules. However using just those figures is a bit like determining a cars performance just by its hp and curbside weight. It would also imply that a Tornado would sail as fast forwards as backwards (OK, I know I just wrote that a Catalac went faster backwards than forwards)
So what next?? Weight and length can be combined into the Slenderness Ratio (SLR). But since most multihulls have similar Depth/WL beam ratios you can pretty much say the SLR equates to the LWL/BWL ratio. Typically this will be 8-10:1 for a slow cruising catamaran (or the main hull of most trimarans), 12-14:1 for a performance cruiser and 20:1 for an extreme racer.
So by and large faster boats have finer hulls. But the wetted surface area (WSA) increases proportionately as fineness increases (for a given displacement the half orange shape gives the least WSA) so fine hulls tend to be slower in low wind speeds.
The most important catamaran design hull shape factor, is the Prismatic Coefficient (Cp). This is a measure of the fullness of the ends of the hull. Instinctively you might think that fine ends would be faster as they would “cut through the water better”. But in fact you want a high Cp for high speeds. However everything is interrelated. If you have fine hulls you can use a lower Cp. Most monohulls have a Cp of 0.55- 0.57. And that is about right for displacement speeds.
However the key to Catamaran design is you need a higher Cp if you want to sail fast. So a multihull should be at least 0.61 and a heavy displacement multihull a bit higher still. It is difficult to get much over 0.67 without a very distorted hull shape or one with excessive WSA. So all multihulls should have a Cp between 0.61 and 0.65. None of this is very special or new. It has been well known by naval architects for at least 50 years.
There are various ways of achieving a high Cp. You could fit bulb bows (as Lock Crowther did). Note this bow is a bit different from those seen on ships (which work at very specific hull speeds – which are very low for their LOA). But one problem with them is that these tend to slam in a seaway.
Another way is to have a very wide planing aft section. But that can increase WSA and leads to other problems I’ll mention in a minute. Finally you can flatten out the hull rocker (the keel shape seen from the side) and add a bustle aft. That is the approach I use, in part because that adds displacement aft, just where it is most needed.
I agree that a high Cp increases drag at low speeds. But at speeds over hull speed drag decreases dramatically on a high Cp boat relative to one with a low Cp. With the correct Cp drag can be reduced by over 10%. In other words you will go 10% faster (and that is a lot!) in the same wind and with the same sails as a boat with a unfavorable Cp. In light winds it is easy to overcome the extra drag because you have lots of stability and so can fly extra light weather sails.
The time you really need a high Cp boat is when beating to windward in a big sea. Then you don’t have the stability and really want to get to your destination fast. At least I do, I don’t mind slowly drifting along in a calm. But I hate “windward bashing”
But when you sail to windward the boat pitches. The sea isn’t like a test tank or a computer program. And here I agree with Evan. Immersed transoms will slow you down (that is why I use a narrower transom than most designers).
I also agree with Evan (and why not, he knows more about Volvo 60 design than nearly anyone else on the planet) in that I don’t think you should compare a catamaran hull to a monohull, even a racing one. Why chose a Volvo 60/Vendee boat with an immersed transom? Why not chose a 60ft Americas Cup boat with a narrow out of the water transom??
To be honest I haven’t use Michelet so cannot really comment. But I have tested model catamarans in a big test tank and I know how inaccurate tank test results can be. I cannot believe that a computer program will be better.
It would be easy to prove one way or the other though. A catamaran hull is much like a frigate hull (similar SLR, L/B ratios and Froude numbers) and there is plenty of data available for those. There is also a lot of data for the round bilge narrow non planing motorboats popular in the 1930’-50’s which again are similar to a single multihull hull.
One of the key findings I discovered with my tank test work was just how great the drag was due to wave interference between the hulls. Even a catamaran with a modern wide hull spacing had a drag increase of up to 20 % when compared to hulls at infinite spacing. One reason why just flying a hull is fast (the Cp increases when you do as well, which also helps). So you cannot just double the drag of a single hull and expect to get accurate results. And any speed prediction formula must include a windage factor if it is to give meaningful results.About 25 years ago we sailed two identical 24ft Striders next to each other. They were the same speed. Then we moved the crew of one boat to the bow. That boat IMMEDIATELY went ½ knot faster. That is why I now arrange the deck layout of my racing boats so that the crew can stay in front of the mast at all times, even when tacking or using the spinnaker.
I once raced against a bridge deck cabin catamaran whose skipper kept the 5 crew on the forward netting beam the whole race. He won.
Richard Woods of Woods Designs www.sailingcatamarans.com
- Tags Buying Advice , Catamaran Designers
Owner of a Catalac 8M and Catamaransite webmaster.
2 replies on “Catamaran Hull Design”
I totally agree with what you say. But Uli only talk sailing catamarans.
If only solar power. You need the very best. As limited watts. Hp.
The closer to 1-20 the better.
Closing the hulls to fit in cheaper marina berth. ?
You say not too close. But is that for sailing only.
Any comment is greatly appreciated
Kind regards Jeppe
Superb article
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The 8 Fastest Cruising Catamarans (With Speedchart)
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Cruising catamarans are some of the most comfortable boats to roam the water, making them fantastic for both long-term voyages and short-term vacations. Still, cruising catamarans can be great racing boats, but just how fast can they go?
Some of the fastest cruising catamarans include the Gunboat 68 (35 knots), Outremer 45 (25 knots), ORC50 (25 knots), FastCat 435 (20 knots), TS 42 (35 knots), and Lagoon 440 (20 knots). Yet, there are many more cats that can reach 35 knots safely.
If you are interested in knowing about the fastest cruising catamarans, I have you covered. I will be discussing some of the most popular, fastest cruising catamarans and the features that make them so excellent for sailors in need of speed. You will learn more about each catamaran’s speed and amenities, and I will let you know a trick or two to maximize your speed under sail.
CATAMARAN | SPEED (Knots) |
---|---|
Gunboat 68 | 35+ |
TS 42 | 35 |
Outremer 45 | 25 |
ORC 50 | 25 |
FastCat 435 | 20 |
Lagoon 440 | 20 |
Privilege Signature 510 (For reference) | 13 |
Fountaine Pajot Astréa 42 (For reference) | 10 |
How Fast Are Cruising Catamarans?
On average, cruising catamarans can reach top speeds of 15 knots , around 17.3 mph (27.84 kph). However, some exceptional, racing-designed cruising catamarans can reach up to 30+ knots in the right wind conditions.
When you want to better understand catamaran hull characteristics, I suggest the book Catamarans a Complete Guide (amazon link) by the president of Aeroyacht catamarans and that you check out my article Why catamarans capsize .
Factors That Impact Speed
Weight & size.
When you consider a catamaran’s speed, you will need to keep in mind the boat’s weight and narrowness. A vessel that can travel at 15 knots will still move slower if the boat is heavy or has a wide, extensive hull. When increasing the total weight of the boat, the boat “sits” lower in the water, thus increasing water drag and reducing speed.
Why trimarans are faster than catamarans!
Now that we know how weight impacts sailing characteristics, it follows that; if you are planning on racing your catamaran, you should remove as much luggage or extra gear as possible. Eliminating as much weight as possible will help you travel at your cat’s maximum speed .
Narrow Hulls
The hydrodynamics of the ship will heavily affect your speed. Narrower boats can chop through the water with less effort, making slender ships with pointed hulls far faster than wide vessels. So if you are looking for the fastest one available, you should look for a slender hull.
Slim hulls vs. space is a common tradeoff for catamarans optimized for family sailing .
Wind will also affect your ship’s speed, so do not expect your cruising catamaran to reach the maximum speed without heavy wind. Generally, cruising catamarans have two large sails (at least) to power them through the water, and some are so efficient that they can travel even faster than the wind.
Although a strong wind is needed to energize the sails and move the boat, too much wind will instead make the sails less efficient, and maximum speed is most often attained at lower wind speeds but with flat water.
Light Weight Materials
Faster cruising catamarans are often made from carbon fiber materials and fiberglass to keep the weight down. If you are looking for the quickest catamaran that you can find, you should note the materials that the ship is made out of and try to get one that is primarily made from carbon, glass, and resin materials.
While you are looking for the perfect catamaran for you, you should keep in mind what you NEED and what is NICE with your ship. Usually, this decision is between size and speed, but some of these excellent vessels have both.
Lightweight materials are usually costly; for example, a carbon fiber mast will probably cost you +$20 000, depending on the cat’s size.
I have written a buyer’s guide that explains the concept of NEED vs. NICE , which will make choosing the right boat faster and more accurate.
Gunboat 68 (+35Kts)
Gunboat 68 is a cruising catamaran designed to reach the highest speeds possible. Made by Gunboat, the ship uses Grand-Prix racing boats’ designs to develop the speediest cruising catamaran on the market.
Gunboat 68 is made entirely from carbon composites, which keeps the ship lightweight and fast. Gunboat 68 is the perfect catamaran for anyone who wants to reach the highest speeds possible while maintaining control of the vessel and not bouncing around too much.
Gunboat 68 has comfortable, spacious living quarters, though it also has a spacious deck with luxurious seating. Indeed, this cat has it all, making it one of the best cruising catamarans for racers and casual sailors. The design maximizes all of the living spaces and uses lightweight materials to add elegance and luxury to a speedy racing catamaran.
Gunboat 68 is one of the fastest cruising cats out there, with its maximum speed at more than 30 knots . Gunboat 68 can achieve these fast speeds, thanks to its lightweight construction and narrow hull design.
Still, Gunboat can customize your ship’s plan to accommodate your needs. Whether you are looking for a faster, more lightweight boat with a more extensive sail or a more comfortable cruiser, Gunboat 68 is an excellent option for you.
Specifications
- Maximum Speed: 35 knots
- Length: 68 ft (20.75 m)
- Beam: 29.9 ft (9.1 m)
- Draft: 3.9 ft (1.2 m) board up and 9.84 ft (3.8 m) board down
- Displacement: 23.7 tonnes
TS 42 (ORC 42)
The TS, or Tres Simple , cruising catamarans, designed by Marsaudon Composites, are some of the fastest cruising catamarans in the world.
Marsaudon developed the ship’s plans using racing boats’ streamlined designs and combined them with a cruising catamaran’s comfortable living spaces. The TS 42 has an inverted hull which helps it glide on the water swiftly without requiring much fuel, but it also has a spacious below-deck area with plenty of luxuries.
TS cruising catamarans are often considered the fastest cruisers on the market, with their speed comfortably reaching upwards of 35 knots in the right wind conditions. Generally, TS catamarans can sail at 20 knots, even with moderate wind. They are the perfect catamaran for racers and high-speed travelers, and yet they still have the amenities of a pleasant live-in vessel.
The TS 42 has a large galley and comfortable cabins, making it a cozy home or vacation vessel. With multiple bathrooms, large windows, and open lounge spaces, these catamarans are superbly comfortable to live in.
The deck and cabin space are divided by a large, openable window, which adds extra light and ventilation to the living areas. It also has plenty of on-deck space, which is rare in such a small vessel with an inverted hull.
If you think I’m using too many confusing nautical terms, you’ll find all the answers on my Catamaran parts explained page .
- Length: 42.8 ft (13 m)
- Beam: 24.3 ft (7.4 m)
- Draft: 4.9 ft (1.5 m) with boards up and 7.5 ft (2.3 m) with boards down
- Displacement: 5.8 tonnes
Outremer 45
Based in France, Outremer (pronounced uutremeer 😉 ) designed their Outremer 45 to be a long-lasting cruising catamaran that sails smoothly at high speeds. The Outremer 45 can reach about 15 knots, but the most comfortable sailing speed is 10 knots. However, it can travel up to 25 knots in the right wind conditions, making it a quick ship with all of a perfect cruising catamaran’s luxuries.
It is made for durability from carbon, vinyl ester, and divinycell so that it can last many years without repairs. The Outremer 45 has a narrow hull, and it is designed to be as thin as possible to maximize speed and fuel efficiency. Outremer 45 still has comfortable living quarters with large windows and lounge spaces within the boat. Indeed, it sacrifices no comfort for speed.
In this article, I talk a lot about catamaran characteristics, both interior and exterior, if that’s something you want to better understand, then I recommend an article where I write about trade-offs in design choices .
The Outremer 45 was initially designed to be a boat that would last 50 or more years, and it excels in its durability. It has an open, uniquely expansive side deck and plenty of on-deck conveniences that make sailing a breeze in the ORC50.
With supreme safety features such as tall railings, slip-free grips on deck, and enclosed lounge spaces, it is one of the safest catamarans available (is safety your top concern? I wrote a list of the safest catamarans on the market).
- Maximum Speed: 25 knots
- Length: 48 ft (14.6 m)
- Beam: 23.3 ft (7.1 m)
- Draft: 3.3 ft (1 m) with boards up and 6.7 ft (2.04 m) with boards down
- Displacement: 8.2 to 11.1 tonnes
Marsaudon Composites ORC50
Marsaudon Composites designed the ORC50, or Ocean Rider Catamaran 50, with both speed and comfort in mind. The ORC50 can be used for cruising, but it is also a great racing boat that has been awarded honors from many races worldwide.
Marsaudon borrowed designs from racing skippers to plan the ORC50, bringing together a cruiser’s comfort with the speed of an award-winning racing boat.
This cruising catamaran is lightweight, which allows it to gain speed at a fast rate, but still has comfortable living quarters inside the boat. It has a rotating carbon mast, which helps to eliminate turbulence over the mainsail and therefore increasing sail efficiency and speed!
With strong winds, the ORC50 can reach up to 23 knots , making it extremely fast for a cruising catamaran. The ORC50 can easily reach speeds much faster than the wind speed, which is a unique quality of this fast, yet comfortable catamaran.
The ORC50 is an excellent long-term living ship with its many organizational compartments, expansive galley, and well-ventilated sleeping cabin. It also has plenty of couches and seating areas built into the boat, and its intuitive design adds plenty of comfort to the cruising catamaran without weighing down the ship.
- Length: 50 ft (15.23 m)
- Beam: 27 ft (8.2 m)
- Draft: 5.6 ft (1.7 m) with boards up and 8.9 ft (2.7 m) with boards down
- Displacement: 13 tonnes
FastCat 435
African Cat’s catamarans, including the FastCat 435, are designed for speed and racing. This ship is mainly composed of epoxy, fiberglass, and carbon components, making it very lightweight to ensure that it travels as swiftly as possible.
The FastCat 435 may be as light as possible, but it is durable enough to last for many years in the most extreme conditions.
The FastCat 435 has comfortable living quarters and well-designed comfort spaces so that you can get the most out of your trips. The FastCat also has a green hybrid design, and it uses primarily electric power, which can help you prolong your sailing and use less fuel.
I find solar-powered/electric cats pretty exciting, so much so that I wrote an entire article called The Best Solar-Powered Catamarans on the subject.
The FastCat is an excellent option for anyone who wants a smaller cat with a comfortable design and incredible speed. FastCat’s electric power is also a unique, favorable feature for anyone who wants to use less fuel.
- Maximum Speed: 20 knots
- Length: 42.7 ft (13 m)
- Beam: 24.4 ft (7.4 m)
- Draft: 3.9 ft (1.2 m) with boards up
- Displacement: 2.4 tonnes
The Lagoon 440 cruising catamaran, like the FastCat, has an electric powering version, which cuts down on fossil fuel usage and ensures that your ship will keep moving. The Lagoon 440 is also among the easiest catamarans to maneuver, thanks to its electric drivetrain and automatic engines.
The speed of the Lagoon 440 usually maxes out at 10 knots with low winds, but with higher winds, it can quickly gain speeds up to 20 knots (some argue even higher, but I’m doubtful). The Lagoon 440 is an excellent cruiser and comfortable catamaran, but it is not an all-out racing cat.
Lagoon is a well-known brand, but there are some caveats, and are Lagoons still making good catamarans?
Below the deck, the living spaces in the Lagoon 440 are magnificent. The ceilings are high, allowing the tallest of passengers to stand in the cabin. The many storage compartments and furnishings have a modern, elegant design. The interior is one large primary cabin with a few private spaces below the deck.
- Length: 44.6 ft (13.6 m)
- Beam: 25.3 ft (7.7 m)
- Draft: 4.3 ft (1.3 m)
- Displacement: 10.5 tonnes
Fountaine Pajot Astréa 42
Fountaine Pajot designs some of the most luxurious yet speedy cruising catamarans available in the world. They are renowned for their safe, durable designs that make sailing a comfortable, relaxing experience. And on a personal note, i think the name sounds beautiful!
Their cruising catamarans use an inverted hull design that has become a signature mark of Fountaine Pajot vessels. This hull type allows the water to pass beneath the ship quickly, which increases the speed and fuel efficiency of the cat.
The Astréa 42’s primary benefit is its spacious, comfortable living quarters and large, open deck spaces. The ship’s interior spaces have large windows, large lounging areas, and plenty of storage compartments.
The cabin’s ventilation is also excellent, which reduces the classic musty smells of sea living. You can also get two different models of this catamaran, either in a one-cabin option or a two-cabin option, making it an excellent vessel for larger or smaller families.
The Astréa is ideal for long-term sea living and family vacations (it is not as fast as some more racing-oriented cats). Although the Astréa is not the speediest cat available, with its speed maxing out at about 10+ knots, even in favorable wind conditions, its luxurious atmosphere and comfortable cabin spaces make up for its relatively slow speed.
Don’t get me wrong, despite its lower speed compared to the boats on this list, the Astréa 42 can still get you places quicker than many other cruising catamarans (and most monohulls). So, if you want all of the elegance and comfort of a cat and are not too worried about racing, this ship is an excellent option for you.
- Maximum Speed: 10 knots
- Length: 41.3 ft (12.6 m)
- Beam: 23.6 ft (7.2 m)
- Draft: 4.1 ft (1.3 m)
- Displacement: 12.3 tonnes
Privilege Signature 510
The Privilege Signature 510 is a long-distance cruising catamaran designed for long-term voyages and sailing in extreme weather conditions. It features a durable, weatherproof design that will protect you from rainy and cold weather while sailing.
The helm and living spaces are completely covered, making it safe to live in, even in cold or stormy weather. It also has an automatic sail adjustment system with the controls at the helm, allowing you to make any adjustments from the helm’s safety and comfort.
Privilege Signature 510 also has an elegant, well-designed living space with plenty of amenities, including an accelerated cooling system, a spacious bathroom and kitchen, and plenty of windows for natural lighting.
With an elegant floor plan, this cozy ship is perfect for long-term living.
The Privilege Signature is not the fastest catamaran on the market, with a maximum speed of around 13 knots. Still, it is one of the quicker cats considering its elaborate amenities and comfortable size.
- Maximum Speed: 13 knots
- Length: 50 ft (15.24 m)
- Beam: 26 ft (7.98 m)
- Draft: 5 ft (1.57 m)
- Displacement: 25 tonnes
Although cruising catamarans are great boats for slowly cruising along the water, they can also be swift, substantial racing boats that reach speeds of up to 35 knots. These speedy cruising catamarans still come with all of the amenities of leisure boats, but they also reach incredible speeds without rocking or tossing.
Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!
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The Cruising Catamaran Performance Debate
Which Cruising Catamaran Performs Better…And Does It Really Matter?
A client recently alerted us to a YouTube video posted by a catamaran dealer that is blatantly misleading and inaccurate. If you listen to this dealer, every catamaran manufacturer, other than the Fountaine Pajot brand, is slow, unsafe, not seaworthy and not fit to be a cruising catamaran.
While we agree that the Fountaine Pajot brand is an excellent product (we sell a lot of them), it certainly is not the ONLY good cruising catamaran in the world. There are many products available that are as good and like so many things, when it comes to choosing a cruising boat, it often boils down to personal preference, especially in this category of cruising catamaran.
2022 UPDATE: You will still find some great information below regarding cruising catamarans, especially if you are in the market to buy one. But lots has happened in the Performance Cruising Catamarans category since this post was written a few years ago, like Catana is back in the game with tons of innovation and a fresh new look. In addition to reading this article, be sure to read:
- 2022 Performance Cruising Catamaran Comparison
- We Bought a Performance Cruiser Catana OC 50
Cruising Catamarans Performance
The dealer in the video our client mentioned to us specifically focused on the superior performance of the Fountaine Pajot compared to some of the competing brands in the cruising category like Leopard Catamarans , Nautitech Catamarans , Bali Catamarans , Lagoon Catamarans , and Catana Catamarans .
The fact is that there is very little difference in speed between similarly lengthed cats in this category. All these catamarans are displacement hulls and they pretty much sail to hull speed with intermittent surfing. Therefore, when sailed efficiently, these cats should have very similar performance.
We hear terms such as power-to-weight ratio (sail area to displacement) bandied about a lot by yacht salespeople of the various boat brands as an indicator of performance. While this is definitely a factor and certainly has an effect on acceleration and light wind performance, it is not the only factor. Some catamaran brands will be faster around the cans in a regatta while others will be better when making long passages.
What one should also consider is that when cruising is that a catamaran’s performance will be dictated by sea state as well as wind speed and direction. In light winds, there will probably be a screecher or asymmetrical spinnaker deployed and in strong winds the sails will probably be reefed. This means that in cruising mode, most sail plans are optimized to the conditions. Therefore, when evaluating a cruising catamaran’s performance, there are many factors to be taken into consideration. This is not a simple cut-and-dried argument.
Catamaran Performance Factors & Calculations
To display the different factors and calculations which are relevant when it comes to catamaran performance, we went to Multihull Dynamics for data and pulled some numbers on the two boats most mentioned in this dealer’s video, namely Lagoon and Fountaine Pajot. Here is what we found on the Multihull Dynamics site:
- Base Speed – An empirically derived indicator of the speed a given boat could average over a 24-hour period (best days run) under a variety of conditions. Here again the Lagoon had better numbers with 9.82 knots versus 9.46 knots for the FP Helia 44 – this explains why the Lagoons are so successful on the long Ocean races like the ARC
- KSP – Kelsail Sailing Performance number is a measure of relative speed potential of a boat. It takes into consideration Sail area, Displacement and length at Waterline. The higher the number the higher the speed predicted for the boat. Here the FP Helia 44 at 6.06 had better numbers than the Lagoon 450 which comes in at 6.02 – the Helia is the lighter boat.
- TR – Texel Rating provides a handicap system for widely varying boats sailing together in a race. The formula is essentially the inverse of the Base Speed formula with constants applied to make the results useful. The Texel rating system permits the calculation of time to sail a given distance. Thus a boat with a higher TR can be expected to take longer from start to finish than a boat with a lower TR. The Lagoon 450 came in at 141 versus the FP Helia 44 at 144.
- Interestingly the Leopard 45 came in with better numbers than the Lagoon and the FP as follows: Bruce number – 1.25; Base Speed 10.65; KSP 7.68 and TR 122.
- The numbers for Antares PDQ44 are very similar to the Helia 44 and Lagoon 450.
- Unfortunately there was no data available for the Bali or current Nautitech designs.
*Disclaimer: All data quoted here was derived from Multihull Dynamics. Catamaran Guru offers the details in good faith and does not guarantee or warrant this data.
>>Click on the pictures above or go to Multihull Dynamics website for a full explanation of the graphs.
While the Fountaine Pajot dealer touts the superior performance of their brand, actual data shows that the Lagoon brand has won more ARC cruising rallies than any other brand of cruising catamaran. These are hardly the statistics of “just a charter catamaran that sails in 50-mile circles and lacks performance”, as is claimed by this dealer. As an example, check out these ARC and ARC+ rally results in which Lagoon consistently features well:
- Spirit, Lagoon 450 Flybridge – 1st Multihull
- Cat’Leya, Lagoon 52 Sportop – 2nd Multihull
- Sea to Sky, Lagoon 450 – 3rd Multihull
- Dreamcatcher, Lagoon 52 – 4th Multihull
- Sumore, Lagoon 570 – 5th Multihull
- Opptur, Lagoon 500 – 6th Multihull
- Lea, Lagoon 52 – 10th Multihull
- 2015: 380 Havhunden, first in ARC+ Multihulls Division in corrected time
- 2013: 620 Enigma, first in ARC+ Multihulls Division in corrected time
- 2012: 560 Feliz, first in ARC Multihulls Division in real time
- 2011: 560 Blue Ocean, first in ARC Multihulls Division in corrected time & third in ARC Multihulls Division in real time
- 2010: 620 Lady Boubou, first in ARC Multihulls Division & 11th overall in real time
This is NOT an indication of how good or bad one boat over another is, but rather an indication of dealer bias ! We are sure this debate will continue but it is our considered opinion that one should look at the overall boat and not be blinded by issues that might or might not be manufactured by over-zealous sales people. As we have said before, it often comes down to personal preference.
Performance Cruising Catamarans
High-performance cruising cats are becoming more popular and there are a lot more on the market than even just five years ago, but it’s not for everyone, especially if you are not a skilled sailor. Daggerboards and bigger rigs require more skill and are not for the average sailor.
We’ve been racing on and off for years on different catamarans and we’ve always had great fun sailing and surfing at speeds of 15+ knots. But as fun as that is, it can be a white knuckled, wild ride in bad conditions and can leave the crew tired and tense because one has to really pay attention. At these speeds any mistake could be catastrophic since there is so much load on the rig. So, make no mistake, sailing fast in less than good conditions is hard work, particularly when you sail shorthanded.
When only the two of us cruise along on our own boat, we really appreciate the pleasure of gliding through the water at 8-10 knots, relaxed and comfortable. Would we love to be able to coast along at a good clip in very light winds? Sure, we would love to own an Outremer or Catana! But that type of performance cat will cost us probably twice the price of a regular cruising catamaran. Is it worth the money for the average cruiser? Debatable.
With the advancement of technology, more people will eventually be able to sail these performance cats skillfully and will be able to afford them as costs come down but until such time, we believe that the average sailor can very happily sail at fair speed toward their destination, safely and relaxed on an average cruising catamaran as discussed above. The fact is, one or two knots of speed, which is what the difference between these cruising cats MIGHT be, will not make or break your passage.
2020 Update: At the time of writing this article, we owned a Lagoon 450 SporTop , not a rocket ship by any means, but a fair sailing boat. We now own a Bali 5.4 catamaran that is significantly lighter and faster in general as a cruising catamaran and we love the extra speed. However, I have to say that this boat is less comfortable underway than the heavier Lagoon. It is more buoyant, a little more skittish and tend to surf much quicker. So one has to pay more attention in more vigorous conditions. It can be tiring on a long passage, but it sure is fun!
Stephen says, “I personally like the Bali because it is a more lively boat and sails very well – when we picked our boat up in France it was completely empty and bobbed like a cork which we were not used to because our Lagoon was a much heavier boat. Since we have now equipped her with all the world cruising equipment as well as big dinghy, etc. she is a little heavier and a lot more comfortable. It is a fact that weight affects performance – the lighter the boat the better performance one can expect. We flew across the Atlantic when we were nice and light but the boat still performs well now that she is at full cruising weight”.
The Bottom Line
So, to conclude this argument, dealers are always somewhat biased about the products that they represent. Manufacturers go to great lengths and spend a lot of money training their dealer networks to be knowledgeable about their products and represent them well with the buying public. They rightfully expect loyalty from their dealers and expect them to present a positive image to the consumer. We all get that. However, when dealers trash and misrepresent their competition with manufactured issues in order to sell their own products, they do a disservice to the buying public and the industry in general.
We want to hear what you have to say! Tell us about performance on your cruising catamaran and also check out our article on why we chose our own catamaran .
Reminder! Check out these fresh updates on performance catamarans:
Contact us if you have any questions regarding catamarans, Fractional Yacht Ownership or our Charter Management Programs .
Estelle Cockcroft
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13 thoughts on “The Cruising Catamaran Performance Debate”
Thanks for a sober writing. I am the owner of the Lagoon 380 Hahunden, and agter with you. I have a spreadsheet with 75 different cruising cat models and the elapsed times in 29 races, and there is not much difference in perforfance. Can send it if uou want. Greetings.
I would like to see that spreadsheet for sure!
I own a Venezia 42′ and if my boat is part of your spreadsheet I would especially love to see it! Could you please send me a copy even if it’s not on there?
To discuss performance and Lagoon or FP in the same sentence is crass. These are not performance Catamarans, purely floating caravans. They have no pretence to performance only cruising capacity, any indicator of performance is purely coincidental.
I own a Privilege 495 and wouldn’t trade it for any other cat.
Hi Jack, I am interested in the performance of your boat. I understand that mini keels decrease performance considerably. Thanks Di
I would like to point out that the data that you use from Multihull Dynamics is completely flawed due to an inaccurate displacement value. Multihull Dynamcis inexplicably lists the Helia at 14 tons, while Fountaine Pajot and your site list the boat at 10.8 tons. This is quite a big difference and skews all the metrics calculated by the site. The Helia is obviously a lighter boat and performance in catamarans starts with weight, so it is undoubted that the Helia will be more lively than the Lagoon. I totally get your point that that does not mean that it will be more comfortable. Second, on the ARC data front: my father sailed twice across the same route in the Atlantic in the last 10 years and I’m very familiar with the conditions. The trade winds there tend to be rather lively and in those conditions weight will matter less. I would expect to see different results in lighter conditions. All that said, the dealer in question is undoubtedly doing their marketing with an agenda.
Hi Ivan, thanks for your input regarding the Helia 44 weight discrepancy. We are aware of this and it holds good for both vessels. You will note that the Helia 44 shows a displacement UNLOADED of 10.8T while the Lagoon 450 shows an UNLOADED displacement of 15T. In order to get accurate performance numbers we assume that Multihull Dynamics have used a number that represents the LOADED weight of both vessels. This means that for the Helia 44 it went from 10.8T to 14.1T (an increase of 3.3T) and in the case of the Lagoon 450, it went from 15T to 20T (an increase of 5T), since it a larger boat overall with more capacity. Based on the above I think we can safely say that we are looking at a fair and accurate comparison. Your input is really appreciated and we are always open to comment and correction to ensure the information we put on the site is accurate and fair.
Thank you for the clarification on displacement.I do see that they have bumped up the Lagoon 450 displacement as well so that’s a fair comparison. I wish they published that clearly because it changes numbers quite a bit as all manufacturers typically post the weight of their boats unloaded.It looks like the Lagoon makes up for the greater weight with a bigger sail area, so that will probably add up to greater effort needed to manage those larger sails but with modern systems, all these things can be managed. Thank you for the clarification and your insight overall.
I think the misconception people have about “performance” catamarans, is that the reason sailors gravitate towards them is not their speed, it is their ability to sail in light air. If you have a catamaran that will sail at windspeed or close to it in 5-8 knots, you’ll actually sail instead of cranking up the diesel. Those true performance catamarans capable of this that also have all the creature comforts of the Helia/Elba45 or Lagoon450/46, are 50+ feet long, and twice the price unfortunately.
You are so right! Well said.
Good article! For me, the weight includes all the stuff you are taking on a month long (or longer) journey (Full fuel +extra cans, 2 sups, dive tanks and compressor, 4 cases of wine…). My opinion is that the performance cats hull design suffers more when loaded to the gills. Ride quality is also very important and is often glossed over by the performance cat advocates.
You are completely right and that was part of strategy when we raced across the Atlantic with the ARC rally. We knew that all the cats would be loaded to the max for the crossing which no doubt makes them less efficient sailing cats. Fortunately on the Bali 5.4 the buoyancy calculations is for a fully spec’d and loaded boat. So we left and sailed like a bat out of hell right off the bat and we were sailing very efficiently, making 200+ NM distances every day. We figured that as the other cats start using their fuel, water and supplies, they would sail a little more efficiently but by then we would be well ahead of the pack, and it worked. We surprised even the very fast performance cats and all the while eight of us onboard were sailing in complete comfort and were eating gourmet meals three times a day! LOL- Of course the TS’s beat us but it is hardly a fair fight. LOL
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Long range power catamarans
Peter Brady provided a brief history ( Multihull World Magazine, #142 ) of how he saw the development of long distance power catamarans:
Arthur Defever 1960’s (“long range cruising” monohulls) –> Robert Beebe 1974 (“passage maker” monohulls) –> Malcolm Tennant 1990’s (catamarans) & Roger Hill 1990’s & Peter Brady 1990’s in Australia (catamarans).
The qualities of the “passagemaker” were defined by Beebe as 2,400nm range at 7.5kn, self-sufficient for at least two weeks.
Brady opines that 2,000nm at displacement speed is a “reasonable bench mark”, with 55-65′ boats making 8kn at “displacement speed”.
This “displacement speed” indication is perhaps a better metric and allows calculation of the standard “ hull speed ” calculation of 1.34 x sqrt(LWL), with a “displacement speed” changing the multiplier from 1.34x to 1x or 1.1x (so a 49′ boat would average 7-7.7kn, a 64′ boat would average 8-8.8kn).
It is worth saying now that many trimarans and catamarans are acknowledged as NOT being limited by this theoretical hull speed as the formula is based on the hydrodynamic (wavemaking) properties, but hulls that are very narrow for their length (some say 8:1 or more on LWL:BWL) may instead be more limited by the interaction properties of the waves off each hull. There is not
So as a working definition, a passage maker or long range cruiser can be classified as being able to go at least 2,000nm on standard tanks at a speed of 6-8kn (depending on length, but 36-64′ covers most cruising size boats).
I have collected fuel consumption, displacement and size for quite a collection of power catamarans that I consider cruising boats. By this I mean they have considerable range and autonomy, have a displacement or semi-displacement hull shape, and can sleep at least two couples. This precludes the larger and smaller fast fishing boats (hull shape; range), patrol boats (comfort; sleeping), and all the smaller aluminium cats.
Based on the data I have collected, for production boats, these are long range passage makers:
- Sunreef 70 – range 3200
- Africat 420 – range 2800
- Fountaine Pajot 46 Cumberland – range 2100
and for non-production boats, these are those I can find enough data to support as long range:
- Tennant 66 Domino – range 7000nm+
- Tennant 60 Catbyrd – range 6000nm+
- Tennant 54 PH8 – range 3000nm
- Tennant 44 St John – range 2000nm
- Roger Hill 66 Tenacity – range 2500nm
- Roger Hill 66 Lola – range 3200nm
- Brady 17.5 Passagemaker – range 3200nm
By definition, these power catamarans (a mix of one-off and production boats) are not long-range:
- Fountaine Pajot 37 Maryland (with 75hp engines, not 150hp) – range 1500
- PDQ 41 – range 1500
- Pachoud 49 Solitaire – range 1250
- Fountaine Pajot 37 MY – range 1200
- Lagoon 43 – range 1200
- Horizon 52 – range 1150
- Fountaine Pajot 35 Highland – range 1100
- Fountaine Pajot 44 MY44 – range 1100
- Ligure 50 – range 1100
- Aquilla 48 – range 1050
- Fountaine Pajot 40 Summerland – range 1000
- Fountaine Pajot 44 Cumberland – range 1000
- Leopard 51 – range 1000
- Leopard 43 – range 1000
and those with less than 1000nm range at the requisite speed:
- Aquilla 45 – range 950
- Leopard 37 – range 900
- Fountaine Pajot 34 Greenland – range 900
- Aspen 120 – range 750
- PDQ 34 – range 680
Going non-production, you are generally into one-off builds. Even though the big-name designers may have sold multiple hulls of the same initial design, these are often modified over the build so that they may only partly resemble each other once finished.
Lastly, the technical list of non-long range power catamarans ignores the fact that all of those referenced have an excellent range of at least 900nm. There are few times in a passage maker’s travels where more range is needed – the Pacific (Panama-Marquesas) and Atlantic (Bermuda-Azores, Cape Verde-Barbados, Cape Town-St Helena) are such, but these are an extremely small part of the time on water a passage maker spends compared to being close to land and places where diesel – quality or not – is available.
As a final warning, almost all of the above it theoretical waffle. It doesn’t take into account some vital points of decision: is the boat designed and built to handle the conditions of a long passage? Are the people aboard capable and ready for such voyages?
If you know of other long range power catamarans and can provide at least three data points of speed-consumption, please let me know and I can add them.
Other interesting articles about power catamarans are:
- Shuttleworth on his Adastra
- Some of Malcolm Tennant’s ideas
- Alex Simonis on the Leopard 43 and why Power Catamarans Don’t like to go Uphill
- Noah Thompson on hull fuel efficiency
and for some first hand information, Domino and SnoDog are fantastic.
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3 thoughts on “Long range power catamarans”
I didn’t know this about power cats. So few go long range! How interesting.
[…] the range you can travel a lot (no ocean crossings and possibly no multi-day trips). We want to go long range cruising […]
Thanks for the sensible critique. Me and my neighbor were just preparing to do some research on this. We got a grab a book from our area library but I think I learned more from this post. I’m very glad to see such great info being shared freely out there.
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Displacement Hull Power Catermaran
Discussion in ' Boat Design ' started by willy13 , Mar 16, 2022 .
willy13 Senior Member
I am planning a build of an aluminum, trailerable, displacement hull power catamaran. Attached is a drawing of the hull shape. Before I go further with the design I wanted to ask a few questions. My wife and I decided that slow and steady is better for our purpose of exploring the Florida keys and eventually exploring the Bahamas. We plan to trailer the boat from NY to Florida and live on the boat for a week to a month during the winter. The current boat length is 23 ft which limits our efficient speed to 7 mph according to Mr. Froude. We chose a flat bottom to reduce draft. First question, am I correct that since it's a displacement hull and the flat bottom will be under water that the ride will not be harsh like a jon boat? I chose a wave piercing bow and a hull that is parallel to the water to prevent planning if the 15hp x 2 outboards can push the speed significantly past 7 mph. Is this correct, or will the hull possibly raise above the water soon after the 7 mph Froude hull speed number? From my experience with displacement pontoon boats I think this boat might reach 14 mph with 15hp x 2. It's hard to predict but fully loaded for live aboard we should be at 5000 lbs to 5500 lbs displacement. I'd like to have the option to cruise slightly above the Froude hull speed, 10 mph. The other reason I chose a flat bottom is it's easy to fabricate from aluminum. If ride quality is an issue I can change to a round bottom. Thoughts?
kerosene Senior Member
1st: I am no professional so gut feel comments not to be taken as truth but purely as comments to advance discussion. -I don't think you will complicate the design much by sloping the front up. Either way I doubt it will slam horribly as the bow is pretty narrow. -With no rocker and deep straight hulls the steering will not be the easiest. -30hp will probably beat the 7mph easily witch such narrow hulls - even at 23ft on flat water. -square cross section is for sure the easiest to make but flaring sides out (wider at the top) would give you much more interior space without compromising waterline beam AND give progressive buoyancy. Also arguably it would be stronger by nature. -keeping the sides parallel gives advantages in modularity of the build etc. but I think you would get better performance with curved sections -Extra chine might reduce wetted surface enough to be worth while. If still parallel sides the extra work should be relatively little. -the rear "rocker" is pretty significant and as the hull keeps the width to the rear that is bound to suck the rear down quite a bit. Keeping the aft wide is ok on an efficient hull but you need to slope up gently (far straighter section). I know the LDL hull by Irens below is quite different in every aspect but still using it as an example. If you want to keep the horizontal straight flat mid section then canoe stern might be a better option. 8ft is pretty narrow imo. Where does the "living" happen? In a superstructure above or in the 4ft tall hulls? (I assume superstructure). Did you calculate the displacement on your drawing?
Thank you for your thoughts. 8ft wide is certainly a compromise, 8 ft 6" is max for NY towing without special signage and what not. The living space will be in the superstructure. This is a vacation live aboard so except at night we plan on enjoying the nice weather. I sloped the rear up so I can reduce running draft when we get in shallows around islands. I assume the prop needs clean water. The outboard height will be adjustable for when in deeper wavy waters. I certainly can make a more gradual slope if I needed. Or canoe the stern if that will prevent the stern from sucking down. That is something I was not aware of so thanks for bringing it up.
bajansailor Marine Surveyor
Just doing some very rough 'back of a fag packet' calculations gives me an approx displacement of 4,300 lbs at a draft of 1.5' (ie wth the transom just immersed, according to your sketch). The hull depth seems to be about 4'? The immersion might be about 400 lbs / inch (for both hulls), so your load draft might be a tad under 2' - 50% of the hull depth. Even if you can build a bridgedeck connecting the hulls that is only 12" deep, then you only have 12" of bridgedeck clearance above the waterline - not a lot when you are bashing to windward. You might well find that the underside of the bridgedeck slamming is more of an issue than the hulls slamming. If your main constraints are approx 24' long and 8' beam, then I think you would be better off with a monohull - that will have an L/B ratio of 3, which is fairly average for a monohull motorboat. And you will then be able to more easily get the necessary volume of displacement for your loaded condition, with a more seaworthy hull shape to boot. Edit - I think you would be hard pressed to find a 'better' 24' power cat than a Woods Skoota 24 for the usage that you have in mind. Note that Richard says that she is 'trailerable' (she is 13' wide), so this must involve some dis-assembly. But Richard is very good at designing multi-hulls that dis-assemble easily. Sailing Catamarans - Skoota 24 trailable centre cockpit weekender https://www.sailingcatamarans.com/index.php/designs-2/6-powercats/263-skoota-24
ziper1221 Junior Member
How will this differ from a pontoon with custom superstructure, or from a small catamaran houseboat?
I canoed the back of the hull. It will be even easier to build. With 15" of draft, displacement is 5616 lbs. I think I did it correct, volume of hull in water (ft cubed) x weight of water (62.4 lbs/ ft cubed). The 2 hulls will share bulk heads. A bulk head at every 2 to 4 feet, can't decide. With 1" flat stock aluminum stringers. Plan is to use .125 aluminum, 5083 or 5086, for everything. The bottom of the cabin floor will be 27 inches above the water. Should that be high enough to reduce slapping in Gulf waters?
ziper1221 said: ↑ How will this differ from a pontoon with custom superstructure, or from a small catamaran houseboat? Click to expand...
messabout Senior Member
So you want to cruise around the keys. Florida bay on the west side of the key chain is skinny water but has lots of interesting things to see and do. The east side is not so friendly in marginal or bad weather. That is the Atlantic side. The sketch you have done needs some help. As Bajansailor has politely implied, you have not built a safe enough reserve displacement into the boat. He has also given some very sound advice, which is, build a monohull rather than a multi. A mono will serve your purpose better in that size range. Your "wave piercing" bow design will give you a very wet topsides if you get into much more than calm water. Even dangerous in a following sea as you have drawn it. And as suggested by others, it will not steer well in any kind of sea state. There are some very experienced and highly competent members here Willy13. They are almost always honest and helpful. Please abandon the notion of designing you own boat. You may be an intelligent and educated person but your first attempt at boat design reveals that you are insufficiently expert in that kind of endeavor. You could actually go to the Bahamas in a 23 -24 foot boat. But it had damned well better be a stout well designed boat if you get into some weather. For example if a northeaster approaches while you are crossing the Gulf stream you are in for a day you will remember forever, if you are lucky enough and a skillful enough seaman to survive. With all that I do hope that you will build a boat and enjoy some wonderful times in the Florida Key areas. Just stay on the west side and find your way up he intercoastal waterways to Miami or around the west southern tip of the bay of Florida and up the coast to Fort Myers or other nice place to visit.. Not to suggest that there might not be some challenges in terms of weather in Florida Bay. Stay safe. Get the plans for a proven professional design and build it. Best of luck to you
BlueBell . . . _ _ _ . . . _ _ _
Willy13, I can see what you're trying to do here, I get it. I've experimented with similar ideas in disposable, rebuildable wood for racing hull sea trials. The difficulty in turning was ridiculous. The 15's would help, but hitting reverse on one, and full throttle on the other, at speed, is not pretty, or overly effective. All the other points raised are valid. Sorry It can't be worded delicately, Bajansailor came close, it's a terrible idea, given the circumstances. Go with the advice offered. I know it's counterintuitive given the Forum name and all. Go with a proven design, in aluminum, and enjoy your sea-time after that long trailer drive. Please.
I now understand the issue with the wave piercing bow, and honestly thought it may be an issue, so the bridgedeck structure and cabin is set back 5 ft from the bow. I thought that there would be enough buoyancy to pop the bow back up before the water slapped the bridgedeck structure with it set back and at only 7 mph. The reason I tried to make this design work is because I thought it would be more efficient than a planning catamaran hull. There are plenty of old aprox. 8ft wide, 23ft long, planning catamaran hulls available with bad motors, that I could throw 2 small outboards on and slowly explore the keys. And maybe thats what I will do, but I am worried about fuel economy with such a setup. I do not understand the recommendation to go with a monohull of the same width when I thought a catamaran of the same width is more stable in the water due to having twin hulls and thus a center of buoyancy for each hull? I also don't understand the reserve buoyancy comment. I doubled checked my numbers and the most draft would be 15" with 27" between the water and bottom of the bridgedeck structure. Certainly at some point the distance between the center of cravity and center of buoyancy may become a stability issue, not sure when that is, but we do not plan on having a tall cabin, and will be storing a lot of water and gasoline as low as possible in the twin hulls. So if we changed the bow to a more traditional planning catamaran bow, is there still no reason to go forward with this design?
Let's see this through with an open mind. Please show, if even simply a sketch, your lay out, preferably to-scale, three-view (front, side, top). Your tank arrangements and all loading (ex. batteries, engines, oil, provisions, safety gear, fenders, crew, guests and their gear, fuel, water, blackwater, hulls, cleats, docklines, etc). Looking for total, worst-case scenario here: wiring, lights, fire extinguishers, dogs, cats, everything. ( flooding? ) You'll want to round, or somehow crown your hull tops for easier re-floating and water shedding (added buoyancy) once submerged. And let's clear up this rookie mistake right away: planing vs planning.
https://www.boatdesign.net/gallery/a0-sport-lounge-boat.7613/full?d=1493444241 This is weird, I log back on and this picture is on the front page. It looks similar to what I want to do but not fast, slow and steady. Did this boat ever get built or did it remain a concept only? BlueBell, I can get more sketches if there is still hope, lol, I only included pictures that related to the specific question I had.
willy13 said: ↑ BlueBell, I can get more sketches if there is still hope, lol, I only included pictures that related to the specific question I had. Click to expand...
BlueBell said: ↑ I will entertain your curiosity. It's your call. What was the question? Click to expand...
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willy13 said: ↑ The reason I tried to make this design work is because I thought it would be more efficient than a planning catamaran hull. There are plenty of old aprox. 8ft wide, 23ft long, planning catamaran hulls available with bad motors, that I could throw 2 small outboards on and slowly explore the keys. Click to expand...
Calculating power requirements for full displacement hull
Displacement hull design for lower horsepower (british seagull)
Hull vane...hydrofoil for a semi displacement cruiser
Semidisplacement cruiser hull
Hull shape: what’s the consensus on extreme piercing/displacement/planing combo hulls for sailboats?
How to make a 19 foot planing hull efficient at displacement speeds?
Hybrid method for semi displacement hull forms (B. Taravella, 2009)
19m semi displacement / planing hull "port service boat", efficient boat plans with carolina lines and down-east semi-displacement hull.
Still Need Input - Questions on Displacement Hull
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Discover the Top Power Catamarans for 2024
- By Yachting Staff
- Updated: September 10, 2024
Power catamarans have seen a surge in popularity, growing both in size and appeal. These cruise-focused yachts offer homelike comfort, fuel efficiency and user-friendly operation, making them a favorite among avid travelers. Their popularity extends to the bareboat charter market for the same reasons.
In this article, we explore the world’s top power catamarans, ranging from a 36-footer ideal for a cruising couple to a 78-footer perfect for entertaining friends and family. The propulsion options are diverse, including outboards, diesel inboards, hybrids, and even all-solar setups.
Top Luxury Power Catamarans
The following power catamarans are all vessels we’ve reviewed. They are listed in no particular order.
- Fountaine Pajot MY44 : A family-oriented cat suitable for long-range cruising and aimed at owner-operators.
- Silent Yachts 60 : This is a catamaran that can cruise comfortably for long distances using emissions-free solar-electric propulsion.
- Horizon PC74 : With interior and deck space like a much larger vessel, the PC74 is perfect for cruising the Bahamas and Caribbean.
- Aquila 36 : This beefy 36-footer is an outboard-powered, express-cruiser-style catamaran.
- Lagoon Seventy 8 Powercat : A spacious design, this vessel fits the volume of a 130-foot-long monohull into just 78 feet of length overall.
- Horizon PC68 : This cat has a stable ride, long range, volume to spare and intriguing layout options.
- Two Oceans 555 : An elegantly simple yet luxurious 55-foot custom with the space and amenities of a much larger vessel.
- Lagoon 630 : From its open salon to its spacious decks, the Lagoon is a comfortable and luxurious platform.
- Fountaine Pajot MY5 : A midsize cruiser with serious big-boat space for family and friends.
- Prestige Yachts M8 : The voluminous 65-footer lets owners customize onboard spaces.
- Aquila 47 Molokai : Calling all anglers: This cat has 60-plus-knot speed and is set up for serious bluewater adventure.
Fountaine Pajot MY44
The Fountaine Pajot MY44 , a creation of Italian architect Pierangelo Andreani and French designer Daniel Andrieu, has a main deck that’s open from the aft-deck seating all the way forward to the starboard helm station. The sense of spaciousness is significant, for several reasons. First, four glass panels aft can all slide to port, creating an indoor-outdoor space with the aft deck and salon. In the salon, 32-inch-high windows extend for 12 feet down the sides of the yacht, with three sections per side, bringing in natural light along with the three forward panes that comprise the windshield. Finally, 6-foot-6-inch headroom provides vertical clearance, with a 21-foot-7-inch beam that adds interior roominess while keeping the yacht stable.
Quick Specifications
44’ | |
21’5” | |
530 gal. | |
184 gal. | |
6’6” | |
32,850 lb. |
Silent Yachts 60
Solar panels, ocean-crossing range and self-sufficiency define the electric Silent-Yachts 60 power catamaran. If there was any question that the “Tesla moment” has arrived in yachting, the Silent 60 clearly provides a positive response. Consider, for a moment, crossing oceans in silence at 5 to 6 knots without consuming a drop of fuel and never needing to plan your course between fuel stops. Imagine sitting at anchor and running the air conditioning all night, not to mention all the galley appliances plus the washer-dryer, without the hum or fumes from a genset.
62’ | |
29’6” | |
4’5” | |
68,000 lb. |
Horizon PC74
As founder and director of The Powercat Company, a Horizon Power Catamarans distributor, Stuart Hegerstrom had long believed that catamaran builders needed to design their yachts to more stylish standards.
“The boats were very boxy,” he says, based on his years of experience with cats in the charter market. He and his partner, Richard Ford, asked Horizon to produce models that had high-end finishes and looked good inside and out.
The Horizon team brought in mega-yacht designer JC Espinosa to work with its own craftsmen. The result aboard the Horizon PC74 is a catamaran with exterior styling, layout and functionality that should appeal to private and charter owners alike.
73’9” | |
28’3” | |
2,000 gal. | |
400 gal. | |
6’ | |
163,140 lb. |
The Aquila 36 is a departure from her sisterships in that she is an outboard-powered, express-cruiser-style catamaran, but she also adheres to MarineMax’s philosophies.
With a single main living level from bow to stern and a beam of 14 feet 7 inches, the Aquila 36 is like a bowrider on steroids. She has seating that can handle 20 adults for outings and barbecues, and there are two staterooms below, one in each hull, for family weekending. The staterooms have nearly queen-size berths, en suite heads, stowage and 6-foot-6-inch headroom.
36’ | |
14’7” | |
356 gal. | |
200 gal. | |
2’ (engines trimmed up) | |
21,572 lb. |
Lagoon Seventy 8 Powercat
Lagoon is a division of Groupe Beneteau, the world’s largest builder of sailing yachts, and the Lagoon Seventy 8 Powercat is a developmental sistership of its Seventy 7 super sailing cat. The Seventy series yachts are built at Construction Navale Bordeaux in France, which had to add a new yard to construct these catamarans because they require separate stern molds for the power and sail versions.
78’1” | |
36’1” | |
2,246 gal. | |
422 gal. | |
4’2” | |
131,153 lb. |
Horizon PC68
Multihull yachts ride differently than monohulls, often counteracting the sea’s motion for a smoother, more stable ride. On the Horizon PC68 , sharp hull entries make head seas seem gentle, and a Humphree stabilization system with blades reduces roll. Horizon uses SCRIMP construction for resin saturation that maximizes strength with an 111,112-pound displacement. And with a 5-foot-4-inch draft, the PC68 invites island cruising.
60’9” | |
24’6” | |
1,000 gal. | |
250 gal. | |
4’9” | |
83,467 lb. |
Two Oceans 555
With 27-knot speed, house-like volume, an on-deck master and top-tier tech, the Two Oceans 555 is a formidable power catamaran. Dave Jirikovic of HMY Yachts was on a quest. The sales broker was looking for the meanest, nastiest patch of Gulf Stream he could find to show a potential client what the Two Oceans 555 power cat could handle. And just as he had intended to show us, the broad-shouldered power cat didn’t even notice. He even dropped the single-lever throttles back to idle and left the 25-foot-wide Two Oceans 555 beam-on to another set of square-edged seas. The 55-footer brushed that off too. Jirikovic tried quartering into the seas—never a happy angle for catamarans—and the yacht drowsed through them.
55’6” | |
25’ | |
750 gal. | |
200 gal. | |
49,600 lb. |
Fitted with the optional twin 300-horsepower Volvo Penta D4 diesels, the Lagoon 630 MY burns only 1.64 gph total at 6 knots, giving a theoretical range of 2,952 nautical miles with standard tankage of 793 gallons. Hull No. 1 had an optional 502-gallon tank, giving it transatlantic range.
Luxury, stability and economy are all hallmarks of Lagoon’s return to luxury motor yachts. If you can take a ride, it will be worth your time.
64’ | |
32’10” | |
793 gal. | |
254 gal. | |
3’11” | |
70,097 lb. |
Fountaine Pajot MY5
The flybridge deck on the Fountaine Pajot MY5 is a standout feature, offering virtually unobstructed 360-degree ocean views and an elevated beach club vibe. Aft of the off-center starboard helm is a spacious area perfect for entertaining, complete with a wet bar, refrigeration center, and ample seating. It’s the most popular space aboard according to the builder. And if the weather turns for the worse, a second helm station in the saloon allows the skipper to pilot the MY5 in climate-controlled comfort.
42’4” | |
19’9” | |
372 gal. | |
112 gal. | |
3’7” | |
46,000 lb. |
Prestige Yachts M8
How fitting it was that Prestige Yachts introduced its new M-Line flagship, the M8 , at Portopiccolo, a picturesque yachting village outside Trieste, Italy. Formerly a quarry, the cliff-side area had been chiseled into a clean site rife with eye-catching vistas, much like the French builder’s 65-foot power catamaran and its nearly 3,000 square feet of usable real estate.
65’ | |
29’ | |
978 gal. | |
224 gal. | |
5’5” | |
98,379 lb. |
Aquila 47 Molokai
With every boat, there’s an origin story. In the case of the Aquila 47 Molokai power catamaran, it starts with MarineMax, which saw people renting boats for bareboat charters. MarineMax Vacations was born. After experimenting with several production yachts, the company decided to build its own: the Aquila line, designed for charter as well as for sale to owner-operators.
49’4” | |
14’7” | |
1,048 gal. | |
2’2” (engines trimmed up) | |
22,818 lb. |
- More: Aquila Boats , Fountaine Pajot , Horizon Power Catamarans , Lagoon , Lagoon Catamarans , Power Catamarans , Prestige Yachts , Silent-Yachts , Two Oceans , Yachts
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by Gregor Tarjan, Aeroyacht Ltd.
Catamaran Advantages vs. Monohulls: Efficiency
Catamaran efficiency can be best expressed in the manner in which certain performance levels are achieved. We will compare the catamaran’s Displacement/Length Ratio, Sail Area/ Displacement ratio and see how the all important stability is achieved in both monohulls and multihulls.
A catamaran’s Power to Weight ratio (or Displacement/ Length D/L Ratio) is one of the most important efficiency indicators of a multihull. The higher the number the slower the boat will sail. The driving power of any sail-driven craft is the energy of the wind acting through the Center of Effort (CE) of the sail plan. The weight of the catamaran is the weight of the structure of the vessel, including its gear and equipment.
D/L Ratio is the Displacement to Length Ratio
D/L= (Displacement in lbs / 2240) / (0.01 * LWL) 3
The higher the resulting number the less performance a catamaran will have. This formula is especially indicative for monohulls, yet comparing a catamaran will show the relative difference. The displacement length ratio is a measure of a boat’s speed potential. For displacement boats (most sailboats), speed potential is a function of waterline length (unless you are planing or surfing down a wave). Longer waterline boats can go faster. Lighter boats accelerate faster and reach hull speed with less wind. All else being equal, the boat with the lower D/L will be a better light air performer. Lower displacement catamarans will also make the yacht more sensitive to loading
A Catamaran’s Power to Weight Ratio or Sail Area Displacement Ratio
SA/D = SA / (Disp / 64) 2/3 This ratio is an indicator of how much sail area a catamaran has relative to its displacement. A boat with a higher value will accelerate faster and get to hull speed with less wind. Again, all other boat parameters being the same, the vessel with the higher SA/D will be a faster a catamaran will be. This is the basic power to weight measure.
Catamaran Efficiency numbers will tell us everything about the potential speed. The two ratios together (D/L & SA/D) can give a good comparison of two boats’ speed potential relative to one another. Taken from the above examples, if our multihull has a SA/D of 27.7 and a DL of 117, and our monohull has a SA/D of 18.9 and a DL of 145, the multihull will clearly be a better performer.
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How Fast Do Catamarans Go? 5 Examples (With Pictures)
A catamaran is generally more balanced on the water and can be faster than a multi-hull vessel.
Unless you compare them to foiling monohulls like the new America’s Cup boats that sail at over 50 knots, they are not recreational vessels.
In this article, we will look at how fast each type of catamaran will go.
Table of Contents
Here are the numbers before we dive into the details:
Sport Catamarans | 30 knots |
Cruising Catamarans | 15 knots |
Racing Catamarans | 45 knots |
Power Cruising Catamarans | 70 knots |
Swath Catamarans | 30 knots |
Average Speed For Sailing Catamarans
Catamarans can vary in size from 14 ft to over 100 ft. Catamarans can come in a wide variety of design types.
Sailing Catamarans have been attempting to make advancements over their mono-hulled counterparts.
These advancements include:
- Foils that assist with lifting the vessel out of the water.
- Stability advancements.
- Racers that can maintain their speed while out in the ocean.
3 Different Types of Sailing Catamarans:
1) sport catamarans.
One type of sailing catamaran is a sport catamaran, which is otherwise known as recreational. These are typically supposed to have a small crew and launch and land on beaches.
Sport catamarans do not normally have living quarters and are ideal for day trips. Resorts or other rental services often use these.
These can also be used for racing.
Sport vessels have been known to travel over 30 knots but can speed over 40 knots in the proper conditions.
2) Cruising Catamarans
Another type of sailing catamaran is a cruising catamaran. These often come with complete living accommodations, so they sacrifice speed over their sportier counterparts.
They can average between 9 and 10 knots, depending on the conditions. The top speed is typically around 15 knots.
It would be best if you were careful with catamarans that have living quarters. The more you weigh it down, the less speed you will have.
3) Racing Catamarans
The final type of sailing catamaran is an ocean racing catamaran.
These boats are large and can reach over 100 feet in length.
The top speed of this type of catamaran is around 45 knots.
Because of the prize money for entering these in races, much research goes into their advancement.
Average Speed Of Power Catamarans
Catamarans with power motors fill a different type of boating category.
These are commonly used when speed and smoothness are favored over space or capacity.
Because of their stability, catamarans are good vessels for combating seasickness as well as transportation. We have a separate article here with all you should know about catamarans and (how to overcome) seasickness .
On a commercial level, these can be used for ferries for both people and vehicles. They are used for short term travel, often to or from islands.
Like sailing catamarans, there are a few types of power catamarans.
1) Power Cruising Catamarans
Similar to sailing cruising catamarans, they also have power cruising catamarans. These also have living quarters and are stable while out on the water. The speed of these vessels highly depends on the motors equipped and the size of the boat itself.
Like passenger transport or ferries, catamarans have a high speed of about 40 to 70 miles per hour.
These are made to travel at great speeds to allow their commuters the shortest possible ride to their destination.
The military also utilizes power catamarans. They use power catamarans to transport military cargo. These ships are ideal because of their speed, holding capacity, and ability to venture into shallow ports.
2) Swath Catamarans
They also have small-waterplane-area twin-hull vessels. These are called SWATHs.
These differ from the average catamaran because they also have submarine-like hulls that stay completely under the water.
Due to the hulls being submerged, they are not normally affected by waves. These are used most often in the ocean as research vessels. They can also be used for certain types of yachts. Because of their stability, they are good vessels for furniture that will not require as much securing.
These often travel between 20 and 30 knots.
Some catamarans are designed for wave piercing. These are made to pierce through waves rather than sail over them, causing them to be faster. These can be used as passenger ferries, yachts, and military vessels as well.
3) Whitewater Catamarans
There are also recreational catamarans made for whitewater travel. These are sometimes called “cata-rafts.”
They are made using two inflatable hulls connected with a scaffold. These are lightweight and perfect for whitewater sports.
They are even able to be packed away in a backpack. They can take up to 20 minutes to assemble, including inflation.
They have high speeds on white water rivers and can be most compared to a canoe, kayak, whitewater raft, or other white water vessels.
Performance Characteristics Of Catamarans
Catamarans require four times the power to double their speed. A mono-hull vessel, however, would require eight times the power to double their speed.
This is because a Catamaran has less resistance in the water.
This is also good for conserving and using less energy.
Catamarans are also more stable in the water. This stability is effective at resisting heeling or capsizing. A multi-hull vessel would require four times the force to capsize as a similar-sized mono-hull vessel.
The general sailing in a catamaran is smoother and allows for activities that are not always possible on a mono-hull sailboat.
Are Catamarans Faster than Mono-Hull Vessels?
Because catamarans have less water resistance, they are generally faster than mono-hull vessels.
This is because their hulls are smaller, which means they have a smaller bow wave to fight.
A bow wave is a wave created by the displacement of water by the bow of a ship. After a certain speed, a boat has to start hauling itself over its own bow wave.
The larger hull a ship has, the larger its bow wave will be and the more power required to fight it.
Catamarans have two small and narrow hulls, so they do not have much of an issue with their bow wave. This is one reason they are usually faster than a similar-sized mono-hull vessel.
Catamarans can be between 20-30 percent faster than their monohull counterparts.
Issues with catamarans over mono-hulls are that they can take more time to turn.
How Is The Speed Measured?
Boats commonly measure speed using GPS tracking devices to measure distance traveled. Speed while sailing is measured in knots. A knot is one nautical mile per hour, which equals about 1.15 miles per hour.
How Fast Are Catamarans Compared To Other Boat Types?
- Sailing catamarans typically average about 10 knots.
- Pontoon boats average about 20 mph.
- A powerboat cruiser can average anywhere between 30 and 50 mph.
- Cigarette boats can even reach close to 90 mph in the proper conditions.
- Sailboats average between 6 and 12 mph depending on wind conditions. This includes mono-hull between 6 to 8 mph and catamarans and trimarans between 9 and 10mph
Two different factors can determine the speed of sailing ships:
1) The hull type as listed above.
Different hulls rest in the water more or less than other types. The less of the hull that is underwater, the faster it can go.
This is because the less of the hull in the water, the less drag created while sailing.
2) The length of the boat
The longer the boat, the faster it can go. Every boat has a maximum hull speed that cannot be exceeded unless the boat can plane on the water’s surface or be lifted on hydrofoils. For most boats, the longer the boat, the higher the maximum hull speed is.
Speed Vs. Comfort Considerations For Catamarans
If you are looking for a catamaran, you have a lot of options.
You can choose to prioritize speed or comfort.
After deciding to purchase a catamaran, the type of catamaran you should look at depends on where and what you are using it for.
You will want to make sure that you look at what type of water you will be traveling in, how many people you are traveling with on average, and what type of speed you hope to achieve.
One thing you will want to keep in mind before the purchase of a catamaran is storage. If you intend to store your boat in a marina, you are often charged for two slips due to the beam, or width, of a catamaran versus the standard mono-hull vessel.
Catamarans can be beneficial for those who get seasick because they offer a steadier ride and the ability to have more open air space. Because the living quarters are not inside the hull and under the water’s surface, you have more windows and visibility.
Both sailing and power catamarans are viable options. Also, sailing catamarans can come with back-up power engines for low winds or situations such as docking in a marina.
Catamarans that have twin engines can offer more control and precision than those on a mono-hull vessel. This is good for tight and busy areas or navigating marinas.
Overall, there are plenty of options for you, and they offer many benefits over their mono-hull counterparts.
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Catamaran Hull Speed
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The hull speed formula for displacement monohulls is 1.34 x the square root of the waterline length. When planing, a monohull will exceed it's hull speed. Obviously this formula doesn't apply to catamarans. Even when not planing, they will travel much faster than what the hull speed formula predicts. Is there a formula or general guideline for catamaran hull speed related to waterline length and / or hull length:beam ratio?
Here, read this ...
Few Catamarans are actually planning vessels. Most are semi-displacement boats (like most modern IMS/IRC derived monohulls). Both forms of semi-displacement boats achieve speeds that are higher than normal hullspeed (i.e. 1.34 x the square root of the waterline length) by minimizing wave production. In the case of multihulls, this is done through a very narrow waterline beam to length ratio, and minimal interference between the waves produced by the other hull(s). Semi-displacement mono-hulls cheat a bit by using very fine entries to minimize the size of the bow wave that they produce. In both cases, clean hull forms and minimal drag is critical to overall performance, but properly designed, semi-displacement boats can achieve sustained speeds that can literally exceed twice their theoretical hull speed without planning. Of course as Alex points out, and as the article that he linked to explains, few cruising cats achieve passage speeds that exceed or even match those of modern performance mono-hull cruising boats. Respectfully, Jeff
Thanks guys.
Damn multis. They leave me standing.
Under body shapes: keels and centerboards, Beam & hull-beam ratios, Beam overall – overall wide beam versus standard beam, Displacement but I can`t find any mention of the optimal hight of the bridge deck cabins, Giuliettas post mentions under deck clearance and it`s extremely important but if you build the bridge on top off the bridge deck would that make it extremely unstable as the center of gravity would be to high making the cat useless in any swell.
sctpc said: Under body shapes: keels and centerboards, Beam & hull-beam ratios, Beam overall - overall wide beam versus standard beam, Displacement but I can`t find any mention of the optimal hight of the bridge deck cabins, Giuliettas post mentions under deck clearance and it`s extremely important but if you build the bridge on top off the bridge deck would that make it extremely unstable as the center of gravity would be to high making the cat useless in any swell. Click to expand...
Yes but what would the optimal height formula be I have been reading for over 4 hours since I read this post and lots of designers mention it but is there a rule to it, 'deck should be 2 foot making cabin 9 foot for a 30 foot cat or deck 4 foot cabin roof 10 foot for a 50 foot cat. I find it interesting that all the other design stuff is quite well out explained but none on windage problems ect.
The less cabin, the better from a windage and weight standpoint. There are various rules of thumb for bridgedeck clearance. .06 x DWL is one. As far as hull waterline beam goes, some say 16 to 1 is as good as it gets from a resistance standpoint. A fast cruiser will be about 12 or 13 to 1, but the shorter the boat, the more beam there will be in the hulls in order to get a reasonable amount of room inside and carrying capacity. 8 to 1 hull beam to DWL length is common in small to medium size cruising cats. Overall beam is usually about one half of the overall length. Recent designs are often somewhat beamier overall-BOA 55% of LOA is not uncommon now. Tim Dunn - 65 Foot Sailing Catamaran Design by Tim Dunn
there isn't a basic rule for bridge deck clearance and cabin height. Some designers avoid the problem entirely by not using the bridgedeck form living accommodations. Wharram's design often don't have any living space on the bridge deck.
Check out Performance Cruising Inc. - The Official Gemini 105MC and Telstar 28 Web - I find the boat to be a best of both worlds design in a smallish cruising catamaran. I am of course partial and biased. The hulls are roughly 8:1 length: beam. I've had mine at 10.3 knts SOG in 16 knts on a close reach (50 degrees off the wind) going up current in 1.25 knts of current. Other owners have reported (and photographed) top speeds of 18 knts, and routinely get 10+. From the side the gemini looks like a moderately high windage mono. That's hard to do with a queen sized bed in the master cabin and twin staterooms aft with double beds. It has 39 inches of clearance at the front it takes chesapeake chop well on the nose, but with only 18 inches at the stern we do get the occasional 'thumb' on the floor of the cockpit. Reportedly they do well in typical ocean swell and have crossed the Atlantic and Pacific Ocean quite well. Several reside in Hawaii, having sailed there on their own bottoms, a couple are currently circumnavigating ( theslapdash.com . By making the salon area standing height for only the walk in area and sitting height at the salon table Tony Smith (the designer) was able to give it a nice profile. Otherwise, headroom is 6'2" throughout. I routinely dock my boat in a cross wind of 5 or so knots and I can tell you it parks and tracks as surely as a car with very little problem caused by windage. Mine:
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Fixed it, thanks.
Bridge deck, pounding, and windage So, 3 feet between the bottom of the bridge deck & the deep blue sea. In some cases long and thin is good but can it be taken to extremes? For example a 50' cat with a waterline beam of 2.5' mathmatically will produce a vapor trail at 35+ kts. In reality though, will it? Since I hate doing time in the hulls of any boat I am going to keep the boat light in terms of gear and have a tapered bridge deck encompassing all accomodations with a profile to the wind of about 3'. Add a nice sail plan and I'm having fun! Or at least that is the current plan. So, any thoughts on the long skinny hull thing?
One other point is the overall beam of the boat, especially in the case of a catamaran matters as well. If the beam is relatively narrow for the boat size, the hull wake from the two hulls can interfere with performance.
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Sailing Catamaran Speed
You’ve probably heard that one of the best reasons to get a catamaran is because they’re fast. After all, there’s a race any time there are two sailboats on the same waterway.
But like all things in boating, speed is a relative term. Catamarans seem fast to those coming from slow and heavy monohull sailboats, but cruising catamarans are still pretty slow vessels. There are indeed high-tech racing catamarans breaking speed records all the time. Still, the vessels that most liveaboard cruisers venture out on are only slightly faster than their monohull counterparts.
For this article, we will look at the types of catamarans people live on and cruise on. Forget about those fantastic America’s Cup yachts or those multihull go-fast fishing boats for a few minutes.
I have had experience cruising and living aboard both catamarans and monohulls. For five years, my wife and I enjoyed catamaran sailing on a Lagoon 380. We then switched—for many reasons—to a Cabo Rico 38. The Cabo Rico is a traditionally-designed monohull with a full keel and a heavy displacement. In other words, it’s about as far away from a “speedy” catamaran as one can get.
Table of Contents
How fast can a catamaran go, measuring catamaran speed, catamaran speeds vs monohull speeds, sailing cruising catamarans, performance cruising catamarans, racing catamarans, power cruising catamarans, catamaran top speed, faqs – how fast are catamarans.
There’s no doubt that catamarans are some of the fastest sailboats around—but there’s also a lot of misinformation and misunderstanding online about how fast they really are.
Realize that not all catamarans are created equally. There are cruising catamarans built to carry their passengers in comfort. And then there are racing catamarans built for nothing but speed. Somewhere in between, there is a poorly-defined category of “performance cruising” catamarans that stir passions.
So, are catamarans fast? Well, it’s all relative. But, if you compare them to monohull sailboats of similar sizes and capabilities, the catamarans are usually faster for several reasons.
The speed difference is even harder to measure in the cruising catamaran category. One of the reasons catamarans beat monohulls during races is because they are built light with no ballast. But a heavily-laden cruising cat ready for an ocean crossing is hardly “lightly loaded.” Will it still beat a similarly heavily-laden monohull? Sure! But probably not by as much as you might think.
Boats measure their speed in knots. Traditionally, this was measured by a tool known as a knot log. The modern equivalent is an underwater instrument with a spinning wheel that effectively measures the speed of the water passing over the hull. So long as no currents are present, that speed will equal the boat’s speed over the ground (SOG).
Satellite navigation allows us to measure our SOG more accurately, but this isn’t a great indication of boat performance since it will be affected by tides and ocean currents.
For landlubbers, one knot is equal to about 1.15 statute miles. So, in other words, when we say that a sailboat cruises at 6 knots, it means it’s going about 7 mph.
But before going any further, consider this—the maximum speed that a sailboat makes is generally a pretty meaningless number. Maybe the knot log pegs to 13 knots for a few seconds, thanks to a strong gust of wind while you’re headed down a large swell. Does this mean you’re driving a 13-knot boat?
A voyaging sailor who has made a long passage will have little interest in this sort of number. When you’re crossing oceans, what really matters is how many miles pass under the keel each day. The more miles you tick off, the shorter the passage. So most sailors learn quickly to look past the “fastest speed in knots” number and find real-world stats on passage miles.
Comparing speeds between radically different sailing vessel hulls is like comparing apples to oranges. Even seemingly similar boats, like “cruising sailboats,” the differences between one and the other are endless.
For example, let’s say you wanted to compare 38-foot monohulls to 38-foot catamarans. The speed of a monohull is limited by waterline length, which means you’d have to look at a hull that is significantly more than 38 feet in most cases. On the other hand, the catamaran is known for long swim platforms on inverse transoms and plumb bows—meaning most 38 foot cats have nearly 38 feet of waterline.
Then, what sort of hull design makes a fair comparison to a catamaran? Would it make sense to compare a transitional, salty 38-footer with a full keel? Probably not. Most sailors interested in the cruising catamaran lifestyle would more than likely be comparing it to a modern monohull with a flatter bottom, fin keel, and spade rudder.
What about the catamaran? There’s a lot of variation in the catamaran field regarding performance. If speed is your goal, you likely want to compare the high-end performance brands—Outremer, Gunboat, HH, and the like. These boats are becoming more popular, but most cruising cats you see on the water are not performance models. Instead, they are the big and comfortable cruisers made by Lagoon, Leopard, or Fountaine Pajot.
Finally, how can you fairly compare the stats? Boats sail differently in different wind speeds and at different points of sail. In other words—there are a lot of variables that make it hard to answer the question, “How fast can a catamaran go?”
Polar charts for each vessel can provide some clues to make a somewhat fair comparison. Polar charts are graphical plots of a sailboat’s performance in different wind conditions and at different points of sail. Manufacturers seldom publish since no two are ever perfectly alike. They are less of a boat specification and more of one sailor’s results for a particular boat. Most owners make their own polar diagrams, but they’re still a tool for those looking to get an idea of a model’s performance in the real world.
Speeds of Various Types of Sailing Catamarans
There are several distinct catamaran classes, and predicting speed means understanding what the designers were building the craft to do. You might be surprised to learn that the first “modern” catamarans popped up in the New England racing circles in the late 1800s. Nat Herreshoff’s Amaryllis is particularly famous from the time .
Since then, catamarans have been synonymous with speed. But in today’s world of many different multihull designs, it’s important to set your expectations accordingly. As you would not buy a Ferrari for its cargo space, don’t expect your minivan to win any races at the track.
Examples of cruising cats include popular models made by the big-three catamaran makers—Lagoon, Fountaine Pajot, and Leopard. However, there are dozens of other companies making these boats. The market and industry for cruising catamarans have never been larger.
Most of these boats are engineered to provide comfortable accommodations for voyaging. They first became famous as vessels for sail charter holidays, where their huge cockpits and private cabins made them much more popular than the smaller and cramped monohull options.
As a result, they’re not built with high-tech components or super lightweight performance rigs. Instead, they’re the catamaran equivalent of a Hunter or a Catalina sailboat—mass-produced on an assembly line. That keeps prices lower than other types of catamarans, but it also means that they’re not winning any races. The makers use traditional layups with end-grain balsa-cored fiberglass to keep costs down. In addition, they usually feature stub fin keels, which are foolproof to sail but will not provide the upwind performance of a lift-making daggerboard.
Still, without ballast and when lightly loaded, cruising catamarans can move. They show their colors in light air when heavy displacement-hulled sailboats usually make their poorest showing. Since these moderate conditions also make for great cruising, these boats can provide a lovely ride in smooth weather.
Cruising catamarans can’t plane or anything, but their narrow hulls create an effect that means they can beat the hull speeds of a similarly sized monohull. Of course, it’s not a precise number since every boat and crew is different, but generally, you could expect speeds to be about one and a half times that of a same-sized monohull.
These catamarans are still rigged for comfort, but they’re built using the highest-quality and lightest-weight materials. While their hulls are rigged for comfortable living, they are generally designed much sleeker than regular charter-style cruising catamarans. The hulls are narrower, and you’re unlikely to see tall flybridges or forward lounge seating.
Several companies are making these boats. But in the world of catamarans, a performance cruiser is the upper end of the market. If you want a car comparison, Lagoons are something like a Chevy sedan, whereas an Outremer is like an M-series BMW. A Gunboat would be even more exotic, like a Ferrari. Not only are they more fashionable brands, but they’re also made to higher standards with cutting-edge designs .
It’s also worth noting that the category of “performance cruising cat” is a sliding scale. Some companies make vessels with better materials and craftsmanship than the cruising cats but aren’t designed for speed. Others build cats that are all about performance with few amenities.
With every new model, companies building these cutting-edge boats are attempting to boost the “performance” and the “cruising” aspect of their vessels. As a result, amenities and speed continue to get better and better.
Any racing sailboat is not designed for comfort. Especially on a catamaran, accommodations take up space and weigh the boat down. True racing vessels are designed to not worry about the crew but optimize every element for speed. Once the boat is designed for the desired performance, they’ll squeeze in bunks and storage wherever they can.
As such, there’s not much point in comparing them to liveaboard or cruising sailing vessels—they are too different. Some modern racing catamarans even fly above the water on foils. This makes for a high-speed boat and a considerable risk for sailors traveling for pleasure. Gunboat tried to make a foiling cruising cat in the G4 model, but it didn’t go so well for them.
Power cats run the same gamut of designs that sailing catamarans do. Power catamarans and sport catamarans designs are popular in powerboat circles for the same reasons they are in the sailing world–their hull designs allow for smaller underwater profiles and high speeds. There are many fast catamarans out there with twin engines and average speeds of well over 70 knots. Most recreational vessels cruise at about 20 knots, however.
Power catamarans also offer a smooth ride, making them a popular choice for large vessels like passenger ferries. There are even military vessels that use two hulls, like the stealth M80 Stiletto .
As you can see, catamaran speeds vary from just slightly better than monohulls to extraordinary flying machines. But cats are about much more than just speed. Their open and bright living space makes living aboard an entirely different experience than living on a monohull. Their cockpits flow into their salons for a full-time outdoor living feel that no other type of vessel can match. There are many reasons to choose a catamaran as a liveaboard sailboat.
How fast is a catamaran?
The answer depends on many other questions, like what sort of catamaran is it? And if it’s a sail cat, how fast is the wind blowing?
Sailing catamarans come in all different shapes and sizes. Some are optimized for living space and comfort, while others are designed with fast cruising speeds being the sole goal of the boat. The Gunboat 68, one of the fastest cruising sailboats currently made, can exceed 30 knots.
The world of power cats is much the same. Some power cats can do well over 70 knots, while most cruising boats top out at around 20 knots.
Do catamarans have a hull speed?
A hull speed is a characteristic of traditional displacement-hulled sailing vessels. The properties of the hull shape under the water create drag that limits the overall speed that the vessel can achieve. Even if you keep adding more power (or more wind), the vessel cannot exceed its designed hull speed for any length of time. Hull speed is a factor of waterline length.
Multihulls, however, have an entirely different underwater profile than monohulls. Their narrow hulls and shallow keels mean that drag is not the limiting factor. With this in mind, designers can tweak catamaran hulls to plane and cruise well above the hull speed of a similarly sized monohull.
What is the fastest cruising catamaran?
The market for fast-moving cruising cats has never seen more innovation than in the past decade. This type of boat has taken off, spurred in part by new designs and the overall popularity of multihulls for cruising. The industry leader in fast multihulls is generally considered the French-based company Gunboat . After all, one of the company’s mottos is “Life is too short to sail a slow boat.”
The company’s largest boat to date is the Gunboat 90 Sunshine . However, the delivery of the company’s current flagship, the Gunboat 68 Condor , from France to St. Maarten, provides some real-world numbers. In the delivery crew’s words, “Our max speed exceeded 30 knots a couple of times, and the max 24-hour run was 328 nm.” To save you the math, that works out for an average speed of 13.7 knots for their best day.
Matt has been boating around Florida for over 25 years in everything from small powerboats to large cruising catamarans. He currently lives aboard a 38-foot Cabo Rico sailboat with his wife Lucy and adventure dog Chelsea. Together, they cruise between winters in The Bahamas and summers in the Chesapeake Bay.
12m Displacement Power Cat
12m alloy displacement hull.
There have been several variations of this design built in NZ by Alloy Cats.
This is a well proven displacement hull cat with a good turn of speed and very good fuel efficiency.
Optimum engine size is around 160 hp for a top speed of around 23 knots. A couple of iterations have used larger engines of 270 hp with a small gain in top speed and no real difference in economy. The larger engines are more difficult to access for servicing in the narrow displacement hulls as well. Some clients prefer to have more than enough power, it’s their choice.
There are several variations available to the original design, wider deck house, longer wing deck, longer deck house, composite top, alloy top, variations in the interior and cockpit layouts, commercial charter use, and private yachts.
One of the great advantages in building in alloy with a ‘base’ design is that these variations are not difficult to undertake as each boat is CNC cut and the design can be easily customised to suit individual client’s requirements, production boat building without the cost of moulds.
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This is the formula for Maximum Hull Speed on a displacement boat: Max hull speed= √((Length on Water Line x g) /(2 x pi)) x 3600/1852. Now we need to add the increased efficiency (loss of drag) of a semi-displacement hull, usually, this is somewhere between a 10-30% increase. Semi Displacement hull speed = Maximum hull speed * 1.3.
And again with displacement hulls, waterline length determines the top speed, so longer is better. The power needed to do 30 knots is about (2) 450 hp or 900 hp. One live example of a displacement catamaran is the HoloHolo on Kauai.
fredrosse said: ↑. Quick and very approximate numbers for displacement craft. Displacement speed (knots) = 1.2 * SQRT ( Length Waterline (Feet)) At that speed normal propulsion is about one horsepower per ton of displacement. The power number here can be +/- 50%, but clearly far less power than your calculation.
In the figures showed in my example attached (speed, heel and displacement predictions in step 6/VPP), dashed lines are used when the windward hull displacement is less than 30% of the total, indicating that it is a more tricky sailing which requires either more attention from the crew (racing approach) or a sail area reduction (cruising approach).
Light loaded displacement - m moc: m moc = 0.8 × m LDC m moc = 5709: The light loaded displacement mass (kg); this is the mass we will use in stability and performance prediction: Beam of sailing catamaran : The beam of a sailing catamaran is a fundamental thing. Make it too narrow, and she can't carry sails enough to be a decent sailboat.
We have now designed a large number of displacement power cats exemplifying the "long and slim" approach of powerboat design. The Zenith-47 displaces 13 tons fully loaded, and motors at 20 knots maximum much more economically at 16 knots with only two 122 kw (160 HP) pushing hulls with a 24.5 knot hull speed.
Hull speed is the speed at which a vessel with a displacement hull must travel for its waterline to be equal to its bow wave's wavelength. A displacement hull travels through water, instead of on top of it as a planing hull (like a kiteboard) would, thereby displacing water with its buoyancy as it sails. The pressure that this displacement exerts on the water creates a wave; this wave is known ...
The formula for the hull speed of a catamaran is the same as the formula for the hull speed of any displacement hull: Hull Speed (in knots) = 1.34 * √ (Waterline Length in feet) How do you calculate the hull speed of a boat? To calculate the hull speed of a boat, you can use the formula: Hull Speed (in knots) = 1.34 * √ (Waterline Length in ...
Hull speed is a crucial concept in marine engineering, which refers to the theoretical maximum speed that a displacement hull can achieve efficiently. The concept is based on the length of the waterline, and the speed is calculated using a specific formula. This article discusses the Hull Speed calculation, its origin, applications, and ...
A discussion about catamaran hull shapes and how they relate to performance and sea keeping with specific reference to the 33' catamaran Mad Max. ... The big one is the displacement or the amount of buoyancy you need. ... but only in the higher speed range. There's a misconception I come across quite a bit that you can add weight and windage ...
Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. ... Such hull forms are commonly used by canoes, competitive rowing boats, catamarans, and fast ferries. For example, racing kayaks can exceed hull speed by more than 100% even though they do not plane.
Plug 1.49 into the hull-speed formula (1.49 x √LWL) and you get a new nominal hull speed of 7.9 knots (1.49 x 5.29 = 7.88), as compared to the boat's old nominal hull speed of 7 knots (1.34 x 5.29 = 7.08). This in itself is an appreciable difference, but it grows even larger as the boat grows lighter. Assume, for example, that our 12,000 ...
If you have fine hulls you can use a lower Cp. Most monohulls have a Cp of 0.55- 0.57. And that is about right for displacement speeds. However the key to Catamaran design is you need a higher Cp if you want to sail fast. So a multihull should be at least 0.61 and a heavy displacement multihull a bit higher still.
Displacement: 8.2 to 11.1 tonnes; Marsaudon Composites ORC50. Marsaudon Composites designed the ORC50, or Ocean Rider Catamaran 50, with both speed and comfort in mind. The ORC50 can be used for cruising, but it is also a great racing boat that has been awarded honors from many races worldwide.
The Lagoon 450 came in at 141 versus the FP Helia 44 at 144. Interestingly the Leopard 45 came in with better numbers than the Lagoon and the FP as follows: Bruce number - 1.25; Base Speed 10.65; KSP 7.68 and TR 122. The numbers for Antares PDQ44 are very similar to the Helia 44 and Lagoon 450.
This "displacement speed" indication is perhaps a better metric and allows calculation of the standard "hull speed" calculation of 1.34 x sqrt(LWL), with a "displacement speed" changing the multiplier from 1.34x to 1x or 1.1x (so a 49′ boat would average 7-7.7kn, a 64′ boat would average 8-8.8kn).
With 15" of draft, displacement is 5616 lbs. I think I did it correct, volume of hull in water (ft cubed) x weight of water (62.4 lbs/ ft cubed). The 2 hulls will share bulk heads. A bulk head at every 2 to 4 feet, can't decide. With 1" flat stock aluminum stringers.
Here, we take a look at 12 catamarans ranging from a cruising-couple-size 36-footer to a 78-footer for friends, family and some more friends. ... This cat has 60-plus-knot speed and is set up for serious bluewater adventure. ... Displacement: 21,572 lb.
A Catamaran's Power to Weight Ratio or Sail Area Displacement Ratio. SA/D = SA / (Disp / 64) 2/3. This ratio is an indicator of how much sail area a catamaran has relative to its displacement. A boat with a higher value will accelerate faster and get to hull speed with less wind. Again, all other boat parameters being the same, the vessel ...
Catamaran Type: Top Speed: Sport Catamarans: 30 knots: Cruising Catamarans: 15 knots: Racing Catamarans: 45 knots: Power Cruising Catamarans: 70 knots: Swath Catamarans: ... A bow wave is a wave created by the displacement of water by the bow of a ship. After a certain speed, a boat has to start hauling itself over its own bow wave. ...
At 34 feet length overall, the Aspen C107 falls in the middle of the Burlington, Washington-based builder's range of high-speed displacement power catamaran designs with an asymmetrical proa configuration. The C107 is based on the twin-hull design that Aspen founder Larry Graf introduced in 2008.
87689 posts · Joined 1999. #1 · Dec 28, 2007. The hull speed formula for displacement monohulls is 1.34 x the square root of the waterline length. When planing, a monohull will exceed it's hull speed. Obviously this formula doesn't apply to catamarans. Even when not planing, they will travel much faster than what the hull speed formula predicts.
The Cabo Rico is a traditionally-designed monohull with a full keel and a heavy displacement. In other words, it's about as far away from a "speedy" catamaran as one can get. Table of Contents. How Fast Can a Catamaran Go? ... let's say you wanted to compare 38-foot monohulls to 38-foot catamarans. The speed of a monohull is limited by ...
12m Alloy displacement hull. There have been several variations of this design built in NZ by Alloy Cats. This is a well proven displacement hull cat with a good turn of speed and very good fuel efficiency. Optimum engine size is around 160 hp for a top speed of around 23 knots. A couple of iterations have used larger engines of 270 hp with a ...