wave piercing catamaran plans

High Speed Catamarans and Multihulls pp 337–367 Cite as

Wave-Piercing Vessels

• Liang Yun 4 ,
• Alan Bliault 5 &
• Huan Zong Rong 4  
• First Online: 30 October 2018

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In the next three chapters, we will introduce a number of hybrid vessel types linked with the catamaran configuration that aim to improve seakeeping and seagoing performance. We start with the wave-piercing catamaran (WPC) and then continue with the small-waterplane-area twin hull (SWATH) in Chap. 9 and other multihulls in Chap. 10 . We will briefly touch on the WPC plus air cushion support in this chapter, SWATH plus air cushion support in the next chapter, and concepts such as the tunnel planing craft (TPC) and super-slender twin hull (SSTH) in Chap. 10 to give a flavor of the challenges presented by hybrid designs and the performance tradeoffs that they introduce. There are similarly a number of options for vessels with a central hull and outrigger support, such as the high-speed trimaran and the pentamaran. These can also employ additional concept adjustments such as hydrofoils to enhance performance. We will give a flavor of these also in Chap. 10 .

• Small Waterplane Area Twin Hull (SWATH)
• Wave-piercing Catamaran (WPC)
• Central Hull
• Catamaran Configuration

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Bliault A, Yun L (2000) Theory and design of air cushion craft. Arnold/Elsevier, UK, ISBN 0 340 67650 7 and 0 470 23621 3 (Wiley), 632 pp

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Rong H-Z (2002) Application of linearized theory of wave resistance to HACAT, SWATH and wave piercing catamaran (in Chinese). Research report, MARIC

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Yun, L., Bliault, A., Rong, H.Z. (2019). Wave-Piercing Vessels. In: High Speed Catamarans and Multihulls. Springer, New York, NY. https://doi.org/10.1007/978-1-4939-7891-5_8

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Professional BoatBuilder Magazine

The breakthrough qe iv ferry.

By Roger Hatfield , Sep 20, 2022

The 104′ (31.7m) tandem catamaran QE IV ferry, built in 2016 by Gold Coast Yachts (GCY) in St. Croix, U.S. Virgin Islands, is an innovative four-hulled vessel that pushed the design and engineering team, the builders, and the U.S. Coast Guard’s certification process to the limits. But the boat has proven a reliable and efficient commercial people carrier in the six years since her launching.

After a decades-long career in the field, I’ve come to define multihull naval architecture as: the use of predominantly lightweight composite materials whose properties can be accurately determined only through exhaustive tests; the placement of those materials in very irregular shapes that are difficult to analyze; and the plunging of these creations into the oceans of the world to be subjected to the occasional rogue wave. It’s a particular moment of glory for a multihull designer who receives approval by some conservative regulatory agency that bestows upon them the permission to operate the vessel commercially.

Mosler’s diverse background includes the creation of Mosler Auto, a high-end sportscar company that uses carbon fiber structures.

This is the story of one such project, the creation of a four-hull 104 ‘ (31.7m) interisland ferry we built and launched at Gold Coast Yachts (GCY) in St. Croix, U.S. Virgin Islands, in early 2016 for our client, St. Croix resident Warren Mosler. With five full years of operation now behind us, we can review the history of this unusual vessel, which has run approximately 100,000 miles carrying thousands of passengers over some exceptionally bumpy Caribbean waters, and declare it a success. But during design development and the build project, that positive outcome was often far from clear.

The quirks of inspiration and fate that created the QE IV started with a sharp businessman’s brainstorm, made real by a successful, innovative boatbuilding company. Wikipedia describes Mosler as an American economist, hedge fund manager, politician, and entrepreneur, who ran for U.S. President, U.S. Virgin Islands congressman, and VI Governor. However, it was his experience as the man behind high-end Mosler Automotive sports cars (1985–2013), and his affection for the island of St. Croix that brought him to this novel vessel design. Gold Coast Yachts had designed and built more than 138 custom multihulls, from racers to cruisers, its bread and butter being commercial Coast Guard–certified day-charter motorsailers, excursion boats, and ferries.

Client Warren Mosler’s first big project with GCY was the 47′ (14.33m) cruising catamaran Knot My Problem, inspired by the commercial fleet of eight wave-piercing cats on the island in 2008.

The genesis of the project began when the fleet of eight GCY wave-piercing power catamarans buzzing around the islands caught Mosler’s eye. In 2008 he contracted the build of Gold Coast’s 82nd vessel, a 47 ‘ (14.33m) wave-piercing, cruising power catamaran, and named her Knot My Problem . We had reluctantly agreed to give the 3D design files of the hulls to Mosler’s car designer so he and Mosler could create the cabin.

The result is an unconventional, voluminous euro-style cabin perched on our slender, wave-piercing hulls. Mosler had employed carbon fiber in his racecars and insisted we save weight in the boat’s superstructure with the same material. Those first components from GCY were simply wet-bagged carbon cloth over foam, but they certainly were stiff, saved weight, and supported the large cabin without adversely affecting Knot My Problem ’s performance. Her name is a tender tease on the island attitude of carefree living as much as a challenge to other boats for rough water speed, seakeeping comfort, and moderate fuel consumption.

Despite that success, we were skeptical seven years later when Mosler approached us with his four-hull project idea. Having built a solid working relationship with him during the 47 ‘ build, we knew we were taking little financial risk and had only to decide if it exposed us to undue ridicule for breaking yachting conventions, insurmountable regulatory challenges, or some long-term liability.

Mosler had set his mind on starting a new ferry system to run between St. Croix and St. Thomas, knowing there was a great need for it. All earlier attempts for ferries had failed for several reasons, primarily structural and economic—the typically rough conditions cracked boats and kept the ridership down. Since most of the ferries were designed to carry 150 passengers (or more), they could not meet their break-even costs. Mosler knew the boat had to be fuel-efficient and comfortable. He was sure he had a solution that he trusted us to realize, and he was not concerned with what others might think about how many hulls it had or its aesthetics. Furthermore, he could afford to turn the boat into his next cruiser if it failed as a ferry.

The view from below convinced designer Roger Hatfield that there could be efficiency in the aft hulls drafting in the wakes of the forward hulls and that the four short hulls might perform better in choppy seas than two long hulls.

Behind the scenes he had started tinkering with two 8 ‘ (2.44m) dinghies structurally joined in an unusual tandem arrangement (one in front of the other). When he started to test-drive it, the boat looked awkward at best, and it rolled a bit, but it was usable. He swore it was awesome and then decided to cut each hull in half longitudinally, closing off the open sides of the four half-hulls to make two sets of mirror-image hulls, still in the tandem combination. He then placed a sturdy deck over the whole thing. We all had another chance to drive this new thing around, and it performed better. It seemed to deal with the oncoming waves more easily, and clearly rolled far less. Thus, the first tandem catamaran was born.

That experimental vessel didn’t prepare me to think in terms of the 100 ‘ boat Mosler was visualizing. I tried to explain the difficulty of taking this crude ¼-scale model and deducing accurate assumptions about a full-scale vessel. The laws of similitude state that any vessel four times as long would likely be four times as wide and four times as high and therefore, for any shape, 64 times heavier.

I was using these physical scaling laws to identify the required power, the likely speed, and the vessel’s motion, but honestly, I struggled with how ungainly this craft would appear. In a moment of self-reflection, I found myself unexpectedly in my father’s shoes. An MIT-trained naval architect, 50 years earlier he had struggled with my fascination with the first modern multihulls. Having grown up near Marblehead, Massachusetts, surrounded by “proper yachts,” he had a distaste for multihulls that was purely aesthetic conditioning. The conventional monohull shape with graceful, long overhangs had started largely as a racing rule-beater and, in my opinion, has set naval architecture back significantly, even until today. Fortunately, my father was able to set aside his prejudice and provide a smart analysis of the multihull’s remarkable potential performance. Faced with another unconventional hullform, I promised myself to do the same.

There were other practical considerations of creating a vessel with no preceding model to draw from. If GCY were to accept this project, we would need up-front money to create a “ballpark” study. We had to sketch it out, create a suitable structure, analyze the weight, and estimate the cost of materials, the potential performance, etcetera, in the head-spinning design spiral of an entirely new hull configuration.

I had always been curious about the infinite variety of hull shapes and combinations skinny multihulls could use. I had spent years pondering and riding on catamarans, trimarans, outriggers, and proas. I image everyone loves to rotate images in 3D, studying things from all angles. The eureka moment for this project came when I drew the 3D concept of the four hulls in tandem and rotated the structure to see it from a fish’s perspective. It was obvious that in this arrangement the aft hulls might be able to gain efficiency by drafting on the forward ones. We’ve all stared up at migrating geese flying in a close V formation.

I have drafted hundreds of other cyclists and swimmers, and though it is best to follow very close, almost any distance reduces your effort. Indeed, triathlon rules suggest that trailing bikes will benefit within as much as five bike-length spaces behind a leader.

Considering Mosler’s passion for automotive design, I began picturing analogous land vehicles. I saw that a boat might operate better in our rough conditions if it were shaped like a four-wheeled jeep rather than like a tank, with its flat tracks forced over the top of every ridge. He separated the hull into forward and aft components. This tandem configuration with its lack of displacement amidships would theoretically ease vessel motion by reducing the tendency for the whole craft to teeter on a crest and then fall into a trough. That, with an attendant increase in overall length, could reduce undesirable pitching motions.

Also, the early hydrostatic studies showed that the proposed boat could be relatively narrow by conventional catamaran standards and minimize the effect of rolling motions. She would benefit by having less of the sometimes-jerky response of a wide cat and yet avoid the slow roll of monohulls, which are frequently not in rhythm with the waves. Finally, the tandem offered a new seakeeping benefit: an unusual escape route between the hulls for big side-slamming waves.

Despite the desire to call this new thing a quadmaran, Mosler insisted from early on in calling it a tandem-cat to better suggest the hull configuration, not just the total number. The boat’s name is simply QE IV. For Mosler, the reference may be to his favorite monetary policy, Quantitative Easing. For me, QE stands for “Question Everything,” something our world could do a bit more of. I can assure you it does not refer to any monarch.

Building the Paul Bieker–designed 53′ (16.15m) all-carbon foiling catamaran Fujin was the project that pushed GCY’s crew, with help from consultant Phil Steggall of Bravolab, to perfect their infusions of carbon fiber laminates.

GCY was fortunate to have this large project following on the heels of our first all-carbon-fiber 53 ‘ (16.15m) racer/cruiser Fūjin , named after the Japanese Wind God. She was designed by Paul Bieker and Eric Jolley of Bieker Boats. Bieker’s and the owners’ acceptance of our shop was, in part, based on our ability to infuse carbon fiber to a high standard. To help, we hired Phil Steggall of Bravolab, who is well known in the world of singlehanded ocean multihull racing. He came to teach us the specifics of carbon fiber infusion and how to meet Bieker’s requirements. We had already infused more than 60 large hulls with E-glass and Corecell foam using epoxies. Thanks to Steggall, our next small step guaranteed quality wetout for carbon and was confirmed through numerous lab tests. (For more on building Fūjin , see Professional BoatBuilder No. 155, Rovings, page 14, and the story behind foiling cruising catamaran Eagle.)

Fujin’s lightweight and functional interior

Learning how to infuse carbon fiber offers several advantages over wet-bagging or carbon prepregs. Wet-bagging tends to yield heavier laminates. It doesn’t remove excess resin, leaving the cloth resin-rich and increasing the potential for thousands of microscopic air bubbles that weaken the structure. As the name implies, prepregs come already pre-wet-out with the correct resin ratios. A potential problem is that they have a finite open time when the material is brought out of cold storage and begins its thermally driven cure. It was always a concern that our shop was located in the tropics and might be vulnerable to the cure happening before the various laminates were ready to be bagged down.

Also, any gaps in prepregs that were not perfectly prefilled in the core remain as voids. With infusion, the time pressure is eliminated. The various laminates are simply laid in place, and once the bag is down and the vacuum pulled, you can pick when to infuse, introducing the freshly mixed resin and catalyst. The actual infusion of liquid resin under vacuum fills every microscopic void before it cures. Careful weighing and testing of panels showed that infusion, which greatly reduced voids, increased the compression strengths. By building with flat-panel methods (or in the curved panels by separating the infusion into steps of outer skin, core, and inner skin) we were able to keep the near perfectly filled panels down to about a 5% weight increase over other processes. That was a fair price to pay, especially in a commercial structure.

The profile of QE IV illustrates how narrow this unique vessel is.

Because carbon fiber has a thinner thread than E-glass, it is harder to wet out. We used carbon cloth developed over several years by Bravolab. It included a 6-gram nylon micro-web as the transfer medium between every 200 to 300 grams of carbon. When we created and maintained a powerful vacuum of 24+ Hg, we created the lowest resin-to-cloth weights and were not restricted by the number of laminates we could infuse in one operation. This vacuum demands a tight mold, a near-perfect seal between the mold and the bag film, and then a myriad of piping that ultimately leads to an industrial vacuum pump, always with a backup pump and generator standing by. To achieve the best epoxy properties, the final step is to thermally post-cure each skin of the panels. Every panel we made for Fūjin was then carefully weighed to confirm estimates and to keep the as-built weight spreadsheet accurate.

The plan views shows how the long passenger cabin serves as the structural box beam at the core of the boat.

Mosler watched the construction of Fūjin closely, especially the state-of-the-art carbon fiber infusion. He saw that he could invest a bit more into his planned ferry to make it lighter and more fuel-efficient. So, his new focus was on a minimum break-even cost, rather than expansive seating for some unrealistic payout.

The primary structure holding the tandem catamaran together would be a long, hollow box (beam) running fore-and-aft, which would also serve as the passenger cabin space. The two forward hulls and the two aft hulls were to be connected to this long box, each with the conservative, proven pair of crossbeam bulkheads typical of catamaran contruction.

With our conceptual analysis completed, we agreed to build the QE IV under one condition: we would have a thorough structural review done by an outside firm. First, we needed a computational fluid dynamics (CFD) study to assess the hydrodynamic pressure loads and the resistances so we could finalize structure and powering requirements. Then, applying fin­ite element analysis (FEA), we could confirm the structures we had estimated by applying the loads from the CFD study.

An exaggerated representation of bending stresses on the cabin structure.

The initial CFD study concluded that QE IV would have relatively low overall running resistance, allowing for smaller and lighter engines and therefore less fuel burn. Later, the FEA analysis would review roughly five million individual elements, each for its fiber direction, its potential failure modes including tensile fiber rupture, the epoxy matrix failure, interlaminar shear, skin wrinkling, core shear failure, and panel buckling. We knew the four hulls had an unusual connective structure; predictably, it needed some effort to assess the suitability of this concept. The FEA revealed global and local stresses, helpfully locating potential hot spots. The entire FEA review took an air-conditioned, room-size, high-power computer more than two weeks to calculate.

This rendering indicates stresses in the cabin sides when slammed by a quartering sea at the port bow.

Every computer geek knows the mantra “garbage in, garbage out” as a reminder that, even run through the best computer programs, nonsense input yields nonsense output. We ran that risk, because our hydrodynamic pressure assumptions that the CFD created drove the entire analysis of the FEA. While our past successful experiences led us to question some of those higher CFD outputs and to be cautious with such an unusual project, we accepted them.

Here the FEA reveals stresses in the crossbeam in the same scenario.

This first run of the FEA indicated that the stress level of most components would pass at the speed and wave heights we thought we would be operating in, though there were many highly stressed localized hot spots. Each set of FEA outputs produced renders and computations. The renders easily located the stresses—red spots showing the highest stress concentrations, yellow and green the medium stresses, and blue indicating very low stresses with the materials we had chosen. We adjusted the laminates accordingly by adding layers in those hot spots and in some instances removing layers.

The three renders above illustrate the vessel being hit by a port bow wave; the render above left is highly exaggerated for emphasis. Note that the boat could never bend like that; carbon fiber is very stiff and brittle. Before launching, when the boat was jacked up under the starboard stern, we were amazed to see the port hull’s stern lifting when the starboard rose a mere ½ “ (13mm). The cabin-side and the beam render are from later FEA evaluations and show few hot spots due to the added reinforcing laminates.

The safety factor rating placed on materials (determined and required by regulatory bodies) is determined by how they respond to long-term cyc­lical loading, which affects not only the longevity of the structure but its initial cost and final overall weight. The working rule for this design was that all areas needed a safety factor of three . The output data with each render included that numerical assessment. A safety factor of one is defined as a slow loading of some structure until it fails. To protect against long-term cyclical loads (usually taken as 10 million cycles) each material has an approximated required value. For steels, because they have been exhaustively tested, the required safety factor value for long-term use is only 2.4. For aluminum it is 3, but for fiberglass layups it is typically greater. Industry researchers suggest that for quality wood and carbon fiber construction, the number could be as low as 2, but there are insufficient test data to confirm this.

Details of the ample laminations connecting crossbeams to the hulls and cabin structure show how the FEA results drove GCY to apply very conservative specifications.

As a prejudiced believer in multihulls, I had been naïve enough to think the U.S. Coast Guard would appreciate the relative safety of this boat. Since the Titanic , everyone has laughed at the idea of an unsinkable vessel. But I saw how some easy calculations could indicate that QE IV would be impossible to sink. In addition, my experience with multihull catastrophes was that they rarely ended up being catastrophic, in part because they typically remained afloat. Because the vessel was so unusual, we got the feeling from the local office and the USCG headquarters that they all hoped the project would just vanish. After our initial structural submission, we received one letter suggesting that we consider applying regulation 46 CFR 177.340, intended for “consideration of alternate design analysis for vessels of novel design, unusual form or special materials.” QE IV unfortunately fit into all of those groups, but that didn’t mean we could use a novel, unusual, or special method of analysis for our project.

GCY shares a laminate schedule.

The certification process with the USCG did not go smoothly. After my retirement in mid-2016, most of the final technical work to get this boat approved had fallen to Karl Peterson, who had become the head of the GCY design team. He reached out to others, including David Walworth of Walworth Yachts, to help coordinate the final approvals. Where we had believed the CFD pressures were a bit high, the USCG thought they were too low and would not trust our database of experience. As the process dragged on, the elephant in the room was the elephant in the shop— QE IV by now was nearly completed.

We finally got a clear directive from the USCG on what it would accept. In essence, the directive was to strain-gauge the completed boat to confirm the FEA, which meant entirely disregarding the CFD study. It was a risky exercise. The proposal was to measure strains in eight predetermined locations, including some that had shown to be hot, while gathering acceleration data at the LCG and at the helm station forward. The vessel would be allowed to operate only within a matrix of calculated speed to wave heights, which depended on the strains versus accelerations. This would be a massive amount of data to collect and correlate. It had to be done with QE IV loaded with drums of water to simulate a full load of passengers and traveling to the nearest NOAA buoy, 35 miles away, that was transmitting real-time wave heights and their periods. The graph above illustrates this collected information combined with real-time wave heights that were measured near the buoy. The top blue curve represents the accelerations at the helm; the red line shows them at the LCG. The graph also shows that the vertical accelerations experienced forward are constantly greater than those experienced at the LCG.

Data from a series of tests of QE IV loaded with drums of water and fitted with strain gauges and accelerometers yielded results confirming that the strains on the roof and deck of the passenger cabin and vertical accelerations at the helm and LCG were within acceptable working norms. The U.S. Coast Guard approved the boat for commercial operation.

Most important is the direct relationship between vertical accelerations from the waves and the vessel stresses recorded below them. As the vertical acceleration increases from bigger waves and faster speeds, the loading on the longitudinal box structure increases, and is seen as increasing strain in the roof and deck. Also note that the roof went into tension as the deck went into compression.

The data allowed Peterson and his GCY team to prove to the USCG that the vessel was satisfactory for service. Mosler had invested a large sum in this FEA analy­sis and the final strain-gauge proof in order to get regulatory approval. In retrospect, the value of the FEA was that it highlighted hot spots and helped create a better distribution of materials than what could have been identified from the first principles. But it was obvious after on-water testing that our original first-principles predictions had been accurate and that the CFD, contrary to the USCG belief, had simply overestimated the loads. This CFD overprediction had forced the FEA to be more conservative, which in turn pushed us to add as much as 1,000 lbs (453.59 kg) of structural materials that will affect fuel burn for the working life of the boat. Perhaps that additional structure will extend QE IV ’s useful life carrying passengers on this rough route, as she has already done successfully for the past five years. Few boats get this much scrutiny.

Having met the structural challenges of the build, we assessed the performance goals of operation. Most importantly, we achieved our fuel efficiency objectives. She typically travels at 19 knots with an average fuel burn of about two-thirds of a nautical mile per gallon. Few vessels are as efficient as QE IV , in part due to her very low weight. She has the incredibly low displacement-to-length ratio of 13.4. She is the same weight and length as the French 30m (100 ‘ ) Ultime maxi-trimarans and half the weight of Comanche , the 100 ‘ ocean racing maxi monohull (see “0 to 60,” in PBB No. 153, page 20).

Do I dare look into the future? Mosler is evaluating a backup ferry that would run in the reciprocal direction to QE IV . Bieker, the foil expert, has observed that this unique catamaran configuration is a near-perfect structure for foils. With a foil on each hull, the tandem catamaran form would be, in the event of a foil failure, an incredible structure to land on. Mosler is wary of the costs to add and maintain foils, even in the open waters of the Caribbean. There is a lot of Sargasso weed, some fish trap lines, and the occasional innocent cetacean. Multihull designer Jim Brown believes that there are many potential ferry routes around the world where using foils might be risky, but for the sake of maximizing fuel and motion comfort it may be worth pursuing this concept. As I suffer from seasickness, I became fascinated early on with the wave-piercing hull concepts. Due to the typically rough Caribbean conditions, 10% of the vessels that GCY has designed and built are wave-piercers simply to improve passenger comfort. Mosler is contemplating a three-hull boat for similar reasons. He is currently investing in a design with a large forward hull with two smaller trailing after hulls. Therefore, my suggestion for this next craft was two smaller torpedo-shaped wave-piercing hulls held way forward, with a large single hull on the centerline aft carrying the majority of the weight.

My takeaway lessons from QE IV are to try not to get trapped in time by prevailing ideas and perspectives, to always be appreciative of time spent on the water simply messing around with boats, and to Question Everything.

About the Author: Roger Hatfield grew up with sailboats. He built a Jim Brown 31′ Searunner and with his wife, Cynthia, sailed into the sunrise in 1977; designed and built a 34′ racing trimaran in 1978; and sold plans for two 34′ trimarans before starting Gold Coast Yachts with Rich Difede in 1983. The company has built more than 130 custom boats ranging from 11′ to 104′, starting with best wood-epoxy building practices for 50-some vessels, then fiberglass and foam infusion for another 70 vessels, plus the two all-infused carbon fiber boats described above.

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What Is a Wave Piercing Hull?

Last Updated by

Daniel Wade

August 30, 2022

Plenty of different sailboats allow you to experience life on the sea. One design that can improve your experience is a wave piercing hull.

Some hull designs are catered to certain outcomes, with many of them being debatable. How is a wave piercing hull different from a conventional hull?

A wave piercing hull does exactly what the name suggests, as it helps cut through waves due to its fine bow and reduced buoyancy. Traditional bows will ride a wave, whereas a wave piercing hull slices right through. The rounded bottom and sharp top of the hull give a boat this unique ability.

While wave piercing hulls benefit from cutting through waves, it does not reduce the ability to stay dry. The main focus of this hull design is to maintain forward speed through a wave, so you will be soaked in the process.

According to experienced sailors, some love to use boats with wave piercing hulls since they have minimal resistance through waves. However, this is debatable for sailors that want a smoother ride.

Table of contents

‍ Positives to a Wave Piercing Hull

Wave piercing hulls are either loved or hated by sailors, but it all boils down to how you want to sail. Depending on your sailing goals, you need to understand that there are many options available to reach those goals.

There are a handful of positives to consider in a wave piercing hull. There are variations of a wave piercing hull, such as an axe-bow or reverse hull, that have slightly different characteristics and can provide positives to sailors.

For example, an axe-bow is meant to help the crew be more comfortable and is better suited for medium or larger waves. The boat size, for this type of wave piercing hull variation, is best for smaller vessels. A reverse hull is another name for a wave piercing hull.

Unique Design

In comparison to a traditional bow on a boat, the wave piercing hull offers a longer waterline length. These boats will submerge in the water during rough conditions, but the top of the bow provides an increase in downforce and allows for buoyancy.

The design also allows it to reduce pitching motion, which is when a boat rides a wave and then drops when the wave is going down. This means a smoother ride all around if you are able to cut through a wave, but arguably a wet one.

Wave piercing hulls are a bit slower and do not accelerate as fast as traditional hulls. However, they are likely to remain at a constant speed since they can cut through waves and help you save on fuel.

This can help, in some situations, remain at high speeds in some cruisers or catamarans. In some smaller vessels, this also has a better effect.

The larger the boat, the better, when it comes to the boat’s ability to cut through the waves. The long length will actually cut through waves a little more effectively than smaller vessels.

Reliable in Rough Conditions

When wind and waves are becoming increasingly dangerous, a wave piercing hull could provide a smoother ride. Depending on the situation, you could potentially make the ride more manageable with this type of hull cutting through rough waters.

Since these designs are fairly sleek and slender, it is easier to turn the boat at a higher speed. If you are in a catamaran, this will likely not be the case since that design is much different even with two hulls. No matter what the marine environment is throwing at you, a wave piercing hull can help dramatically in rough waters.

Compared to other traditional hulls, these offer less vibration and noise. When cutting through a wave, you are likely going to feel more than just some vibration, but the overall comfort is much different than a traditional hull.

Drawbacks to Wave Piercing Hulls

Not everyone enjoys a wave piercing hull and that is perfectly fine. Every sailor is going to have their preferences, especially with the traditional boats being the most common.

You could argue that these boats are an acquired taste and need some experience to perform confidently in them. There are definitely some negatives to look at before you decide to purchase one.

Since you are cutting through a wave instead of riding it, there will be water everywhere. On a racer or cruiser, it might not be that big of a deal since they usually experience a lot of water anyway, but on a catamaran, this might not be favorable.

As mentioned, you are not riding a wave’s pitch and are cutting through the water. If you are doing any long trips, this might be undesirable.

If you were to ask an experienced sailor which they would prefer, being dry and safe would be the universal answer all the way around. However, that does not stop many sailors from enjoying the benefits of a wave piercing hull.

Potential Dangers on Deck

Since the deck is constantly wet, this could cause some issues walking around or trying to remain stable on your feet. The slippery surface is one hazard to deal with, which seems to be something sailors are just going to have to deal with.

The other issue is that if you have guests or your crew walking around while you are trying to cut through a wave, they are at risk of being swept off of the deck. If the wave is strong enough, it could potentially push someone off of the deck.

It does not appear to be a friendly environment to be in when waters become rough, especially when the front of the boat is going down into the water. This could also increase the risk of the boat capsizing if mishandled.

Motion and Pitch

If you are used to being on a boat that follows a wave’s pitch, then you are not going to find that here. Following a wave’s contour is not what these hulls are designed to do.

In some instances, too long of a bow might create too much yawing motion or side to side movement. This all depends on how you encounter the wave, but the boat might not be desirable for some sailors.

This will be a new feeling if you are used to riding a wave’s pitch and might even create seasickness for some sailors or their crew. If possible, you might want to experience a ride on one yourself before committing to one.

What to Expect with a Wave Piercing Hull

Out of all of the pros and cons of a wave piercing hull, it is up to the individual sailor on what they could do with or without. Depending on your desired sailing experience, this type of hull could work in your favor.

If you are trying to optimize the best resistance for waves, then a wave piercing hull is a proven design to help combat pitch. Keep in mind that you are going to be wet, essentially the entire time you are on the boat.

You would likely need to utilize clothing fit for wet conditions and quality shoes to help remain stable. You also might want to plan out your trip for shorter stops to make sure you are not overwhelmed in the process.

One of the best things you can do is take a ride on someone else’s wave piercing hull boat and get a good feel for what is going on. This way you can try it and work any issues out so to speak before you decide to buy a boat with this hull design.

Keep in mind that the perfect bow is not going to exist, so take into account what you want to accomplish. Compared to a traditional hull, this could potentially be the hull design for you if you are up for te challenge.

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HSV-2 Swift (High Speed Vehicle)

The HSV-2 Swift (HSV 2) is a chartered high-speed vessel of the US Navy Military Sealift Command. The hybrid wave piercing catamaran was designed and built by Bollinger / Incat.

35 (total people - 353 maximum)

Bollinger / Incat

Length – 97.22m, beam – 26.6m, draft – 3.43m

Displacement

Four x Caterpillar 3618 diesel engines at 7,200kW

38kt at 627t deadweight, 42kt at 300t deadweight

Four 0.5C M2 Browning machine gun stations

The HSV-2 Swift (HSV 2) is a chartered high-speed vessel of the US Navy Military Sealift Command. The hybrid wave piercing catamaran was designed and built by Bollinger / Incat in Hobart, Tasmania.

It is the fourth high speed catamaran built by the partners, after HMAS Jervis Bay, HSV X1 Joint Venture and TSV 1X Spearhead. The HSV-2 Swift is also acting as a prototype for the joint high speed vessel (JHSV) programme.

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The HSV-2 Swift is owned and operated by the New York-based shipping company Sealift. The HSV-2 was leased by the US Navy and delivered to the Military Sealift Command from Lockport, Louisiana, in August 2003.

The vessel was built for the Navy in eight months from the award of contract. Sea trials of the HSV-2 were conducted from February to May 2004. She was designed to conduct sea basing tests and support transformational mine warfare modular payloads.

The vessel has a crew of 35-18 military personnel and 17 civilian contract mariners from the Seafarers International Union and American Maritime Officers.

The vessel serves for 11 months of every year and participates in exercises such as Southern Partnership Station by USSOUTHCOM AOR. The HSV-2 catamaran currently serves the navy in humanitarian missions, experiments, training, exercises and fleet support operations. In April 2011, the vessel was deployed in the disaster relief operations in Haiti.

Design and features of the chartered high-speed vessel

The HSV-2 is an all-aluminium naval vessel. It is 97.22m long and has a beam of 26.6m, a draft of 3.43m and a mission deck of 2,601m2.

The 24.7m x 15.24m helideck of the vessel is NAVAIR certified to carry helicopters such as the AH-1, MH-60, CH-46 and UH-1. She can also accommodate about 350 personnel and military equipment, or a payload of up to 500t at a top speed of about 35kt.

She has space to store and maintain two MH-60 choppers in weather protected space. A ramp at the stern allows loading and unloading of military vehicles of up to 11,793kg, such as an M1A1.

The vehicles are moved to and fro the flight deck using a crane that supports 9,979kg RIB or small craft launch and recovery.

Accommodation onboard HSV-2 Swift

The HSV has 170 sleeping berths, crew storerooms and 128 aircraft-style permanent seating and 122 temporary seating, configurable to additional berthing for 87 people.

It has a 39-seat crew mess / day. Other amenities include laundry space, medical space, a planning room, sanitary and watertight storage spaces, office spaces and computer workstations.

Safety systems, propulsion and performance of the US Navy Military Sealift Command’s HSV 2

The vessel is equipped with two marine evacuation systems consisting of a 17m inflatable slide with SOLAS A pack life rafts for a total capacity of 500 people.

A 30hp SOLAS RHIB dinghy acts as a rescue boat and another 7m RHIB stowed on the deck can carry about 15 personnel. It is also mounted with four 0.5C M2 Browning machine guns.

The HSV is powered by four resiliently mounted Caterpillar 3618 marine diesel engines. Each of the engines produces 7,200kW at 35/53oC and has a vertical dry exhaust system.

Four Wartsila LIPS LJ120E waterjets allow the reverse and steering of the vessel. Four ZF 53000 NRH gearboxes provide the transmission.

An active Maritime Dynamics ride control system with fold-down T-foil, bow fins and trim tabs aft increase passenger comfort. The HSV-2 Swift has a minimum operating range of 1,100nmi at 35kt and can be operated 24 hours a day at speeds of 3-10kt.

It does not need tugboats for pier assistance and can manoeuvre in waters of depths as low as 12ft.

Command and control

The catamaran is equipped with a Mine Countermeasures Squadron Staff (MCMRON) designed command and control (C2) facility. It provides commercial and military satellite communications and has all digital switch transceivers allowing HF, VHF and UHF communications.

The main deck has a combat information centre (CIC) with workstations and tactical displays, a mission planning and post mission analysis room, a conferencing facility and manned equipment space.

A 700ft² upper C4ISR room and a 200ft2 lower C4I equipment room supply 70kW for electrical and climatic control requirements.

A multicompartment and an equipment room is connected to the command centre configurable to allow five independent missions.

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Saint John Paul II High Speed Wave Piercing Catamaran

Saint John Paul II is a high-speed vehicle passenger (RoPax) ferry built by Incat Tasmania shipyard in Hobart, Australia, for Virtu Ferries, a Maltese ferry services operator. It is the world’s second biggest catamaran to operate at more than 70km/h.

Vessel Type

High-speed catamaran ferry

Virtu Ferries

Incat Tasmania

Construction Started

February 2019

Length Overall

A contract worth approximately $80m for the design and construction of the ferry was awarded to Incat Tasmania by Virtu Ferries in October 2016. The planning and design phase of the project lasted for approximately one year.

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Construction on the ship began in 2017 and its launching ceremony was held in December 2018. The ship was delivered in February 2019.

The wave-piercing catamaran joins Virtu Ferries’ existing fleet of 14 high-speed craft. It allows the company to provide year-round fast-ferry services between Malta and Sicily in the Mediterranean Sea basin with increased reliability and passenger comfort.

Saint John Paul II catamaran design

Saint John Paul II  features a wave-piercing  catamaran  hull structure with two slender hulls built using welded and bonded aluminium. The hulls are connected by a bridging section. A wave-piercing type bow is installed in the centre line to provide increased speed and a comfortable voyage at sea.

The high-speed catamaran is built in line with the standards of DNV-GL classification society. Design techniques and safety features of the ferry are designed in compliance with International Code of Safety for High Speed Craft (HSC) 2000 adopted by the International Maritime Organization (IMO).

The ferry complies with the requirements of Italian Port State and is registered under Malta Flag following the receipt of necessary approvals.

With a dead weight of 1,000t, the vessel can carry up to 900 passengers. The overall length and breadths of the vessel are 110.6m and 28.2m respectively.

Deck details of Saint John Paul II

The high-speed wave-piercing catamaran vessel is equipped with two passenger decks, containing four lounges.

The interior is designed to offer three classes of seating with economy, VIP, and business class. It incorporates 996 indoor passenger seats and 138 outdoor passenger seats.

The garage deck of the ferry can accommodate up to 23 heavy commercial trailers / 167 cars / 490 truck lane metres.

Up to two rigid hulled boats are carried at the stern of the ship to for transportation at sea. The boats are launched or retrieved using a crane.

Operation and control of the vessel are performed from the wheelhouse located amid ships. Marine radars and  communication  systems are fitted atop the wheelhouse to ensure safe operation of the ferry.

Large windows on the passenger deck and bridge areas provide an unobstructed view of the sea.

Propulsion details

The Saint John Paul II RoPax ferry is powered by four MTU 20V 8000 series diesel engines, each generating an output power of 9,100kW.

The vessel’s  propulsion  system comprises four Wärtsilä LJX 1500 SRI modular waterjets, which ensure fast and reliable operation of the ferry by providing a 10% reduction in weight and improved fuel efficiency.

The high-speed wave-piercing catamaran is installed with a Lipstronic control system, also developed by Wärtsilä, for controlling vessel speed, relative load, pitch and rotations per minute (rpm).

Saint John Paul II performance

Virtu Ferries’ new wave-piercing catamaran has a service speed of 38k. The ferry is capable of completing its journey from Malta and Sicily in approximately 90 minutes.

The ship’s slender demi-hulls provide low wave-making resistance and high transverse stability.

Contractors involved

Incat Tasmania awarded a contract to Wärtsilä in April 2017 for the supply of water jet cutters.

Australian company Revolution Design provided design and architectural solutions for Virtu Ferries’ new RoPax ferry (hull number 089). The ship’s design was also supported by Seaspeed Marine Consulting.

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WAVE-PIERCING BOW TECHNOLOGY EXPLAINED

by Gregor Tarjan photo:  Billy Black

Wave-piercing bows – or reverse or hammerhead bows are part of today’s cutting edge naval architecture and the latest thinking in go fast comfort. Versus conventional overhanging or straight stem bows, wave-piercing bows are reversed and are designed to cut through waves, increase performance by reducing pitch resistance. The added benefit is not only higher speeds but a much more comfortable motion at sea.

There are several reasons to consider designing a boat with reverse rake bows. The primary rationale why we consider this hull shape is to reduce pitching motion caused by waves of certain amplitude and frequency. I think an easy way to explain it is this: Assume you are sailing along in smooth water with a conventional shaped hull with no pitching motion. Along comes a single wave. As your bow starts to penetrate into the wave, you pick up buoyancy in the overhanging bow region. The boat reacts to this increase in buoyancy by pitching bow-up. As the wave passes under the boat, the bow then must fall back to equilibrium. The more reserve buoyancy the wave sees as the bow penetrates through the wave, the more pitching moment is imparted onto the boat by the wave and the greater the potential for pitching motion. So if your bow has a lot of overhang or flare (vertical angle of the hull sides), then you naturally have a lot of reserve buoyancy high up in the bow region and this may result in excessive pitching motion. Of course the downside to a reverse -wave piercing bow might be a slightly wetter ride on a small multihull such as a beach cat, but on cats larger than 35′ this is hardly an issue.

Morrelli & Melvin designed 62′ catamaran

Why do we care if the boat pitches? Because pitching increases hull resistance, reduces the efficiency of the rig and underwater foils due to unsteady flow, and causes motion discomfort for the people on the boat. In order to keep the boat from pitch poling (or turning back over front), you need a certain amount of buoyancy forward. On a wave-piercing type bow, this buoyancy and lift are achieved by making the hull fuller down low. On some wave piercing designs, the hull is wider at the waterline than at the deck, especially near the bow. The wider, flatter underwater shape provides lift at high velocities and dampens pitching at all speeds. Other benefits of wave piercing bows are reduced weight and wind age. You can really feel this difference on medium displacement and light weight multihulls. The older designs with tall bows get pushed around in higher wind and sea states whereas the newer wave piercers are easier to steer and maneuver in waves.

Variations of these shapes are now making their way into some larger racing and cruising designs – such as our own, giant Aeroyacht 85′, 110′ and 125′ catamarans. Other boats worth mentioning are the Morrelli Melvin 62′ and 65′, some McConaghy multihulls (from 50-80′) the advanced Neel 47′ and 51′ trimarans and the new range of Sunreef custom catamarans. The faster and longer your boat, the more sense reverse bows make. Today even America’s Cup racing yachts all feature reverse bows and they are definitely part of our boating future.

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Six Amazing Boat Hull Designs

• By Dean Travis Clarke
• Updated: October 25, 2016

The American boating consumer bears a remarkable psychological profile when it comes to wants and needs.

A cursory glance at the lines of most boats proves that profiles haven’t changed dramatically over the past 60 or so years. Certainly, construction methods such as resin infusion and injection molding have altered business as usual, and ingredients have also changed to include all manner of space-age composites, epoxies, paints, computer mapping for engines that produces vastly greater horsepower from smaller blocks, and so on. Even propulsion has changed with the advent of pod drives and big outboards. But here’s the weird part: Any time a designer or builder introduces a model that looks significantly different, whether it is Euro-styled or functionally clunky, it fails. It doesn’t matter how well the boat performs, the typical boater rejects it because it doesn’t look like what he knows. We, as an enthusiast niche involving boats, are horribly set in our aesthetic ways.

Look at how well multihulls handle heavy seas. When it comes to seakeeping ability, efficiency and performance, the catamaran has a lot going for it, as anyone who happened to catch some of the most recent America’s Cup racing can attest. And yet, to date, production multihulls have enjoyed only moderate acceptance by boaters.

Here are six of the latest hull-design innovations and technologies being used elsewhere in the maritime world that we will likely never accept for our recreational boats — even though they all work well.

Wave-Piercing Hulls Most accounts cite wave-piercing technology as coming on the scene around the start of the 20th century. However, it has been employed as far back as the times of the Phoenicians and ancient Romans. The design concept consists of a bow with little buoyancy, a hull that slopes inward from the waterline and, ergo, a large reduction in wave-making resistance. While it works well in heavy seas, the drawbacks include reduced interior volume forward and a very wet ride because the waves come up and over the bow as a matter of course. Wave piercers fell out of favor for a period of time due to these same drawbacks but have recently enjoyed a resurgence of popularity because of their dramatic fuel-efficiency gains.

Stepped Hulls OK, this hull form has achieved a certain level of acceptance in our recreational boats, mostly in performance boats or offshore center consoles. But why isn’t it more popular? The stepped bottom has been around as a V-bottom refinement since at least 1912. Steps are grooves in the hull stretching outward from the keel to the chines. Most hulls sport one or two steps per side. And a vessel should really be capable of cruising in excess of about 30 knots for a stepped hull to be worthwhile. Steps work by allowing air to be “injected” against the running surface, breaking contact between part of the hull and the water, which in effect turns the running surface into numerous short, wide planes, rather than one long, narrow one.

How much the hull surface contacts the water directly determines the amount of drag a hull suffers. Steps (also called vents) decrease the amount of hull contacting the water (called the wetted surface), thereby decreasing drag, increasing speed for the same horsepower, and increasing fuel efficiency. It all sounds good. But steps also come with potential drawbacks. Though modern deep-V designs have enough deadrise to counteract the problem in most cases, stepped hulls have been known to suffer from transom slide in sharp turns at speed. They also require attention to loading and trim because the steps need the proper angle of attack to function correctly; they don’t offer an advantage in flat, calm water; and they require a special trailer.

Most owners of stepped-hull vessels are experienced and want to travel at high speeds in moderate to heavy seas, and/or achieve good economy and range. Yet to date, performance and center console builders aside, only Regal Boats, with its FasTrac hulls, and Formula have committed to using steps in production cruisers and sport boats.

Asymmetrical Twin Hulls This unique design concept comes from the drawing board of Larry Graf, the pioneer who put power catamarans on the map here in the U.S. when he founded Glacier Bay Boats in 1987. His new company, Aspen Powerboats, employs a cat design where one hull is narrower (35 percent) than the other. His patent calls it a Power Proa, and it relies on a single engine in only the wider of the two hulls. The hull shapes, alignment and placement compensate for the offset propulsion thrust, allowing the vessel to run straight and true. With only one set of running gear in the water, inherent appendage drag is reduced by 20 percent. Combined with the efficiency of the hull designs, overall fuel efficiency of the Aspen rises to an impressive 70 percent over monohulls of comparable size. Aspen won an award for the best 30- to 39-foot catamaran in the world in 2014.

SWATH A quick glance might lead you to believe that a SWATH (small waterplane area twin hull) vessel is a catamaran. And it is but only to the extent that it has two hulls in the water with a bridge across the top. But that’s where the hulls’ similarities end.

Consider a submarine. Once under the surface, it runs stable, with no roll or pitching from wave action. All that wave energy remains on the sea surface. That basically explains how a SWATH design functions.

If you’ve ever dived under a wave at the beach to avoid being smacked by it, you know that the water beneath the wave is calmer. SWATH minimizes a vessel’s volume where the water meets the air (which is where all the wave energy is at its peak). The bulk of the vessel’s displacement and buoyancy runs beneath the waves, affording amazing stability, even in big seas and at high speeds. Please think of high speeds as a relative term here, as this is not a planing hull. What SWATH does provide, however, are a wide, stable deck and unsurpassed ride quality, especially in rough seas.

Drawbacks to SWATH designs include the fact that each hull must be custom designed. Draft runs deeper than standard hulls (especially planing hulls). The underwater “torpedoes” providing buoyancy must run parallel to the water’s surface, which requires a fairly complex trim-control system. And the underside of the deck must be far enough above the sea surface to avoid waves slamming up into it. Finally, SWATH vessels cost more to design and build than conventional hulls.

Hydrofoils Once the strict province of commercial ferries and a few high-speed military vessels, the most recent America’s Cup has spurred hydrofoil acceptance to new heights. Will it catch on with powerboats?

The hydrofoil design acts exactly like an airplane wing, providing more lift than the drag coefficient the vessel produces, thereby lifting the entire hull out of the water. Only the hydrofoils remain in the water, unaffected by surface wave action. In fact, hydrofoils cut inherent resistance to zero while the hull is out of the water. In the case of power-driven boats, you still suffer drag from the propulsion system (prop, shaft or the like).

The most significant disadvantage to this system on recreational boats is definitely the deployment of the foils. Unless you want the added draft of these struts sticking down below your hull all the time, you must be able to extend and withdraw them — a complex engineering feat. There is at least one recreational powerboat employing hydrofoils: Twin Vee builds a catamaran with foils that don’t actually lift the hulls completely out of the water. It does improve fuel economy and ride stability nonetheless. Still, boats ride more smoothly in a sea and go much faster with hydrofoils. With the dramatic acceptance of this technology in sailing, is it only a matter of time before recreational powerboats incorporate foils into their designs?

Ulstein X-Bow The Norwegian Ulstein Group has been designing offshore vessels since 1917. Presently, it has the notoriety of creating the most advanced bow design in history. The Ulstein X-Bow looks like it might be upside down, but it’s proven itself in more than 100 offshore support vessels to date. The X-Bow allows higher speeds and smoother rides in even the worst seas. Gone are the slamming and vibration that occur when the bow of a ship drops off a wave. It functions better on all points of sea, and its lower hydrodynamic drag substantially decreases fuel consumption. The X-Bow has proven so successful that Ulstein is in the process of creating an X-Stern design now.

You won’t ever see this on small recreational boats, but you can nod knowingly when someone points one out on a mega-yacht in the near future.

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INCAT Wave Piercing Catamaran

• View history

The INCAT Wave Piercing Catamaran is a ship in DSSIII was added in Update 43 on August 1st 2022. She was modelled by Zarozema.

• 1 Information
• 2 Exterior Description
• 3 Interior Description

Information [ ]

The INCAT Wave Piercing Catamaran is an express ferry in DSS 3. It is currently the fastest and only express ferry in the game. It costs 8 million credits to purchase and has a basic income of 8,100 per nautical mile, making roughly 116,000 credits from Wolin to Puerto Ushuaia . (At upgrade level 3.) The ship is based on the INCAT Wave Piercing Catamaran, which is currently the fastest ferry in the world, setting a record at 58 kts. (45 kts at level 3 in game). The Wave Piercing Catamaran is built by INCAT in Tasmania, Australia.

Exterior Description [ ]

The Wave Piercing Catamaran is easily identified by its two hulls, and a body on top with 2 car decks and 1 passenger deck, and all the way on top is the bridge. At the rear of the ship there are 4 chimneys, 2 lifeboats, an outside deck and the 2 car decks, which are open at the rear of the ship. You can also see the car deck from a large hole in the top of the ship, near the front. The name of the ship is seen twice in the front, near the cleats. In the rear, the name is seen twice underneath a small balcony on both sides of the ship.

It is currently not possible to apply your own livery.

Interior Description [ ]

The interior of the Wave Piercing Catamaran is very detailed. The first 2 decks, as seen from the sea, are car decks. Both decks have yellow lines for the cars and are supported in the middle by yellow beams. In the front of the ship is a curved ramp, to get to the second deck. The rear of the ship has a bridge which the player can control, to allow the cars onto the boat. The 2 skins of this boat remove this bridge, and replace the bridge with a fence, which the player can still control. At the rear of the ship is an elevator, which is not usable in the game.

The passenger deck has a modern feel, with a brown/grey-ish wooden floor & walls. The seats all feature a blue carpet underneath them. The seats themselves are red, with a metal base & arm rests. The middle section of the ship has airliner style seating configuration at the sides of the ship, 2 wide. Everything away from the sides of the ship are 4-seaters, with a white table between the seats. The middle section also features an empty buffet in the middle. At the rear of the middle section there are 2 lounges, and staircases to the car deck and side exits of the ship. The rear of the passenger deck features a small bar, with empty shelves. The seats here are the same configuration, but sometimes feature 3 wide seats. Near the front of the rear section there are seats without tables, but there is a tv hanging from the ceiling. The front of the passenger deck only has seats with tables, with mulitple tv's hanging from the ceiling. The front part of the front section has brown seats, presumably more comfortable, since they are the seats with the best view. The front has the same bar as the rear of the passenger deck.

The bridge has white screens & dials, with several seats.

The INCAT is a ferry ship and therefore its best route is Wolin - Ushuaia . She makes 680k per hour, the same as the Spirit-class Oil Tanker . The INCAT is a important stepping stone from the G2-class Carrier to the Ace-class RO/RO in the recommended grinding path.

The INCAT has two extra skins, the Express Skin and the Reef Skin.

Gallery [ ]

• This is the first express ferry ship to appear in a game.
• This is second catamaran vessel to appear in a game, after the Sailing Catamaran
• She was modelled by Zarozema
• The Lead Developer SyntaxConnoisseur has his own custom livery which is featured in the Gallery
• The INCAT has approximately 417 seats in it (including the driver seat) making it the ship with the most seats
• 1 Upcoming Update
• 2 Greyhound-class Ocean Liner
• 3 Ace-class RO/RO