iom yacht class rules

IOM success

Where might we go from here.

My first thought was to simplify the measurement of an IOM, and thus to simplify the class rules.  After a couple of years of trying to simplify the rules, I realised they were about as simple as they could possibly be and still achieve a "home-build one-design".  [Yes, indeed!  For those doubters out there, I invite you to have a go yourselves at simplifying the IOM rules and still end up with essentially the same boat.  Jan always reminds me that the apparently "simple" IOM class is achieved by "complex" rules.  There seems to be something of an inverse relationship between the "simplicity" of a class and "complexity" of the rules.]  The idea, of course, is to maximise the appeal of the class to the club skipper, to encourage its increased adoption in countries where it has not yet achieved a significant position, and to minimise regulatory and measurement problems and overhead.  I now think that the IOM class association should introduce an IOM design which is a strict one-design hard-chine hull (the Boxkite is on offer from Graham Bantock) with materials restricted to wood only in both hull and appendages.  This kind of IOM would use "normal" measured IOM rigs and sails, but ball-raced goosenecks or jib swivels would not be permitted.  Using an idea of Charlie Coventry, whenever this kind of design races with other IOMs, the other IOMs would have 2 points added to their score in every race of that event.  We might call this kind of IOM the BOM -- the Box One Metre and provide it with its own class rules.

Following this idea, and taking it one step further, is to introduce a "manufacturer" IOM.  This design would consist of a complete kit of materials and fittings, needing only radio control to go racing.  Its rules would be very simple -- you can use only what is in the kit, and you have to use it the way the kit instructions say.  This would be the MOM class, and it would have its own class rules.

My second thought a while ago was to improve the standard of sailing at IOM events.  We now have umpiring at International events, and this I think is an excellent development.  So my second thought now is to give experimenters and tinkerers a class to play in as well -- a "Marblehead" IOM, if you like.  So I think the IOM class association should introduce a kind of One Metre, where there are no restrictions on materials or fittings, while keeping the "normal" IOM length, weight, and overall draught limits for a mono-hull, and the "normal" IOM dimensions for the sails.  Everything else is "free".  Extending Charlie's idea, every such "unlimited" One Metre would have 1 point added to its score when racing.  We might call this kind of One Metre the FOM -- the Free One Metre, and again provide it with its own class rules.

While the BOM and MOM could measure as an IOM, the FOM obviously would not.  The FOM's attraction is that it conforms to the IOM "core" idea -- a minimum displacement in a one metre length with standard size sails -- while allowing itchy fingers and enquiring minds to enjoy freedom...  Neither the BOM, MOM, nor the FOM would be "International" classes, but who knows what time might bring us if boats were built and raced in these classes around the world?  It might be worth being clear that none of these ideas actually affect the IOM class and the IOM class rules -- these continue exactly as they are.  If you are interested in reviewing and commenting upon the proposed BOM, FOM, and MOM class rules, e-mail me and I can send you a document.

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Class Rules 2018

IOM Questions and Answers (Q&A)

IOM Measurement Forms 2018

(effective 1st March 2018)

Certification Control Form

The class rules allow pigmentation of resins used in the moulding of hulls and the difficulty in examining the interior of many hulls , the declarations required on the Certification Control Form require the builder of the hull to declare that the materials used in the construction of the hull / boat are in compliance with the class rules . The simplest way to deal with the Declaration would be for the builder to include a pre-signed Certification Control form with the boat at delivery to the owner. Alternately if a completed boat is not being delivered to provide a declaration that to the best of his knowledge the components supplied meet the requirements of the class rules .

The Certification Control Form remains the only form required to be sent to and retained by a NCA as the result of a successful certification control . The method of storage is the NCA’s decision.

Additional Rigs Form

Should the boat be certificated with less than the full complement of rigs then the Additional rigs Certification Control Form may be used to add additional rigs to a certificate .   Once the certificate has been up dated then it need not be retained.

Check Lists

The two Check List forms are for the measurers use in conducting a certification control .   They are not required to be sent to the NCA. As such, these check lists should be thought of as a work sheet of checks to be observed by the official measurer in a control only and if the boat complies with all the statements then there would be no further use for them. The check lists might be of some use to the owner of a boat which failed control as a record of what has to be corrected before a certificate is issued.

Measurer’s record

This is not part of the Certification Control Forms but is only given as a suggestion of a means of a measurer recording measurements he, or she has completed.

The term builder on the Certification Control Form is to be interpreted to mean the person who assembles the boat to sailing condition from its individual components.

The builder should then satisfy him, or herself, that the various components meet the current class rules .

Where there is any doubt as to the components compliance, the builder should ask his supplier to provide a declaration certifying the component being supplied complies with the current class rules .  This should be available to the Official Measurer at certification control .

In the case of a hull the moulder may wish to add a declaration for this purpose to his moulder’s tag.

Such a declaration should not be confused with the boat’s certificate resulting from control.

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The International One Metre (IOM) class is a 1m long hull with 1.7m mast height and a minimum weight of 4kg. The class rules are very tight and limit yachts to 2-function control and 3 one-design rigs. Hull, ballast, draught and construction materials are also limited. There is sufficient freedom to allow different hull and fin/rudder shapes to be developed.

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Click the picture to get to the boat's page The IOM Class The International One Metre class was created by Jan Dejmo, with the support of Graham Bantock and the Permanent Committee of the ISAF-Radio Sailing Division, and adopted by ISAF-RSD in 1988. The intent was to pull together a variety of "One metre" class rules from different countries, and provide for a common, restricted, inexpensive international class of stable, easily-built designs. The result is the most popular RC racing yacht class in the world. The class has enjoyed such success because competitive IOMs can be built by an ordinary modeller at home, and due to the class restrictions competitive boats remain competitive for a number of years. IOM rules The performance of a RC yacht depends on hull lenght, beam, displacement, sail area, bulb draft, ballast ratio and rig plan. The only parameter than can be freely changed is the beam, all others are restricted by the IOM class rules. Therefore it is primarily differing beams and positions of maximum beam, which distinguish the different IOM designs. In addition to performance factors, the class rules explicitly restrict certain materials and construction methods in order to keep the class inexpensive and able to be built by an amateur builder. Radio control is restricted to two channels. Appendages and sails can be made of any material. A competitive boat can be built at home.

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Status of Class: Adopted Administrative Body: IOMICA

Since its inception in the late 1980’s the International One Metre (IOM) has become the most popular class in the UK.

Sailed at most clubs on a regular basis it is now the class that creates the largest fleets, with regular fleets of 30 boats at district level and a maximum entry at most international events. The class rules for the International Classes are governed by the International Radio Sailing Association (IRSA) and IOM ICA.

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International One Metre (IOM)

Sanctioned in 1998. The International One Metre (IOM) is the fastest growing class in the world. The rules in this class are identical to those used throughout the globe. The class has a one-design rig and weight minimums, but the hull design is very much developmental.

IOMs Are Sailed At...

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Close of 2023 Message from NSWRYA President

Nswrya 2023 iryc iom invitational report.

International One Metre Radio Sailing Great Britain

About iom gbr.

IOM GBR is the class owner group for IOM RC yachts in the UK. It represents the class to the IOM International Class Association (IOMICA) who manage the class globally on behalf of World Sailing.  This includes ensuring that IOM owners are able to propose and vote on proposed changes to class rules, including administration, to IOMICA.

Any MYA member with a registered IOM is automatically a member IOM GBR, further registration is no longer required.

IOMICA have responsibility for:

The World Championships

The European Championships

The IOMICA Annual General Meeting

More information on IOMICA can be found here

The International One Metre Radio Controlled Yacht

  “The first boat in my life that didn’t require a mooring, dinghy park space, launching trolley, foul weather gear or harbour dues and gives me two days sailing a week. Fantastic!”

To find a club nearby click: Here or send us an email from the Contact Us   page if you can’t find what you are looking for.

Enthusiasm for the sport is addictive, many clubs have ‘guest’ days, some have loan boats, and all will welcome you to their community.

The IOM is a great boat to sail and its rules and measurement are relatively simply allowing the amateur and professional alike to exploit hull shape/fin/mast/ deck configuration - Steve Taylor

History of IOM RC Yachts

Created in 1988 by Jan Dejmo, the IOM class rules were written to enable boats to be built from scratch or kit by non-expert builders and inexpensively by a commercial builder without disadvantage to either group.

or glass re-inforced composite with carbon fibre being allowed in the construction of the fin and rudder. 

Spars shall be of alloy or timber and the sails are to 'One Design' sizes, with the number of rigs is limited to three.

Hulls must be constructed of either wood as this beautiful example

This makes  the class very popular for amateur builders and many designers have plans for competitive boats. There are a number of Builders here in UK and overseas,  who can supply plans for home completion, hulls and rigs or complete boats.

A limit of three different rig sizes allows sailing in most conditions from a lazy summer day to winds gusting over in excess of 30kts!

These boats, which handle beautifully, are fast, responsive and quite addictive. Once you have experienced  sailing one, there is no going back.

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The International One Metre (IOM) class is a 1m long hull with 1.7m mast height and a minimum weight of 4kg. The class rules are very tight and limit yachts to 2-function control and 3 one-design rigs. Hull, ballast, draught and construction materials are also limited. There is sufficient freedom to allow different hull and fin/rudder shapes to be developed.

• Latest videos, from 2020

Show photos from latest 2024 2023 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995

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