Rules & Documents

General Moth Class Information

Length overall 3.355 m
Beam 2.250 m
Max. luff length 5.185 m
Max. mast length 6.250 m
Hull weight Unrestricted, general weight range 10-20kgs
Rigged Weight as little as 26kgs
Sail area 8.25m
Restrictions Multihulls, trapezes, moveable seats and sailboards are prohibited.
Optimum skipper weight 60-80kgs
Advertising Category C (unrestricted)

Official International Moth Graphics

Download the official Moth symbol as prescribed in the IMCA rules and by ISAF:

Notice from the IMCA President regarding 2012 IMCA Annual General Meeting

Dear Moth Sailors,

Notice is hereby given that the 2012 Annual General Meeting of the International Moth Class Association will be held at Campione del Garda, venue of the Zhik Nautica Moth Worlds 2012, on Friday 24 August.

The following are links to the relevant meeting documents which I encourage all members to read:

To elaborate further:
Firstly, since the last AGM in January 2011 a significant amount of work has been done behind the scenes by the Rules Working Group to produce an updated set of rules that brings the us in line with how we build and use our boats today. A large part of this has been around the resolutions of the 2011 AGM to allow wing-sails, how this affects the one-sail rule and thus how to measure and treat solid wing-sails; however this process has also uncovered a large number of areas of concern within the rules which the group has also proposed tidying up. Chief Measurer Adam May and his working group are to be commended for the enormous amount of work they have put into this project.

Secondly, following resolutions at the 2010 & 2011 AGM's concerning the addition of a Vice President & Chief Measurer position, an updated constitution has been drafted adding in these two positions for the Council of Presidents to ratify at this AGM.

A 2/3 majority of votes present at the AGM is required to ratify these new documents, with the constitution coming into effect immediately and a proposed date for transition to the new rules of 1 October 2012 (subject to ISAF approval)

Should members have questions regarding any of these documents please contact me at

With 108 boats and 20 nations already registered for the Zhik Nautica Moth Worlds 2012 this promises to be one of the greatest events in the 84 year history of our class and I look forward to seeing everyone in Campione next month.

Mark Robinson
International Moth Class Association

Notice from the IMCA President regarding wingsails

Dear IMCA Members,

Thank you for the prompt responses to your own national Presidents on the vote to amend the 2011 World Championships NOR and thus allow wingsails to be measured and compete; or not to amend the NOR.

The Presidents of all national associations have responded with the vote being 30 in favour of option 1 and 6 in favour of option 2.

We will therefore be proceeding with issuing an amendment to the NOR under the guidance of and with approval from ISAF. Chief Measurer Adam May is currently working with ISAF on the final text and I expect this to be released shortly.

Mark Robinson
International Moth Class Association

Applications for recognition of National IMCA status

Dear National IMCA Presidents,

Applications for recognition of National IMCA status, together with proposed constitutions, have been received from Austria, Singapore and Spain. The IMCA Executive has reviewed the applications and hereby grants provisional membership to IMCA AUT, IMCA SIN and IMCA ESP to be formally ratified at the 2011 AGM.

The office bearers and contacts are:

IMCA AUT (Austria)

President: Nikolaus Liebscher
Secretary / Treasurer / Measurer: Doug Culnane

IMCA SIN (Singapore)

President: James Cole
Secretary: Paul Runyan
Treasurer: Nick Wykeham-Martin

IMCA ESP (Spain)

President: Pablo Arandia
Secretary: Alan Hillman
Treasurer: Simon Fisher

Chris Graham
IMCA Secretary

Important changes to class rules for 2009 European & World Championships


Dear Moth Sailors,

As per the decision at the 2008 AGM, ISAF have now approved class rule changes in the following two areas, these rules are now in effect and thus will be valid for the 2009 European Championships in June and the 2009 World Championships in August.

The first rule change is that now boats that were first measured after 1 Jan 2005 can only carry sails measured to the new "true area" method.

Boats first measured prior to this date may continue to carry sails measured to the old method.

The second major rule change is that now it is legal to pump twice for each wave or gust or to promote foiling after each tack or gybe.

Repeated pumping as we have seen in some events is still illegal, as is any more than 2 pumps in an attempt to promote foiling in marginal conditions.

RRS 42 thus still applies and boats may be protested and/or disqualified for repeated pumping.


Mark Robinson
IMCA President

  • The summary of class rule changes can be found here
  • The full current class rules can be found here here

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