Class Rule Interpretations

In our inaugural International Class Association world council meeting, John Tushingham provided this insightful perspective on the class rules:

One of the founding principles of the rules is that when you purchase a stock boat, pull it out of the box, rig it according to the instructions, then you should be able to go to any event and be competitive and class legal.  What we also don’t want to see is an environment were people feel they need to do extra changes to be competitive.  The rules aim to ensure that a standard specification boat is always completely competitive.  The rules are there, in part, to help support our inclusive founding principles.

John Tushingham

Many of you will be aware of the various social media groups for the classes and how there are many people who try hard to help a newcomer with a rules enquiry but often only succeed in getting lots of other people involved with the usual outcome being somewhat unsatisfactory for all.

The purpose of this page is to give everyone an easy to access to offical class rules interpretations, and outline the procedure that should be used to seek guidance and clarification on current rules.

Current Interpretations

The ICA Class Rules Sub-committee is responsible for issuing class rules interpretations. The Interpretations are published below.

8th December 2022 – Rule Clarification for DF95 Rule H.2 Sail Construction

Question submitted by Dave Bell (GBR)

I would like to seek clarity on DF95 rule H.2.

Sails Construction

“The Jib and Mainsail of any given rig size shall be constructed from the same ply. “

It would appear that there is some confusion as to whether this simply means that;

1. A suit of sails should be made of the same base material of the same cloth weight (thickness) as in Mainsail and Jib are both 35um Mylar film.

2. A suit of sails must be cut from the exact same piece of cloth. 

Logic would indicate that the former be true, allowing for replacement of individual sails should damage to an individual sail occur. Or use of the end of one roll, before starting the next.

However; this seems to be contradictory to the option of some who believe that ply is defined as “a sheet of sail material” or “SAME piece of cloth / material” and as such, a suit of sails would need to be only ever produced from the exact same piece of film / material.

I’ve had a look at the ERS, and cannot obviously see a clear definition. Please could you seek clarity?

Many thanks



In both the DF65 &95 rules, Rule H.2 states “Construction shall be a soft sail of a single ply. The Jib and Mainsail of any given rig size shall be constructed from the same ply.”

The Equipment Rules of Sailing has the following definition: 

G.1.4 Sail Construction
(b) PLY
A sheet of sail material which may be made up of a number of layers.


If they are any visual, textural or colour differences between two sails in the same set, they cannot possibly be made from the same ‘Ply’ (sheet of material), therefore they do not conform to the class rules. This also covers different colours of the same brand of material e.g. Icarex.


The class rules are written in their simplest, clearest form to do away with almost all event measurement requirements. They are restricted class rules where, if it does not specifically say that you may, then you shall not. It is impossible to foresee every innovation which may be thought of in the future. Therefore when considering anything in connection with the boat or its sails or equipment (including choice of materials for any item) which is not clearly covered by the plans, specifications and/or rules, it must be assumed illegal unless prior approval has been obtained from the DFICA.

Whilst it may not be possible to be 100% certain by visual inspection that a jib & mainsail are manufactured from the same sheet of material (Ply), any visual or textural differences between the sails is enough evidence to indicate that they are not, and will be enough evidence to rule those sails out of class. Clearly any difference in colour, apart from permitted decoration, shows that they are not from the same sheet of material and is enough to have them ruled out of class. 

If a sail becomes damaged and subsequently replaced, provided there is no apparent visual or textural difference to the other sail in that set, then is is reasonable to assume that it is made from the same Ply. If the damaged sail was manufactured by Joysway (The Licensed Builder) then it can be replaced by another Joysway sail of the same design despite any apparent minor visual or textural differences, provided you are not substituting an older woven sail for a newer Polyester film sail, or vice-versa. 

Issued by the DFICA Rules Committee

8th December 2022

14th June 2021 – New DF65 and DF95 class rules issued. No current interpretations pending.

28th May 2021 – Clarification on Repairs to Hulls

So, it seems that there has been some confusion on the issue of repairing DF hulls that have broken and how that repair might affect the use of that repaired hull in another event in the future. Rather than have a million opinions on it and have everyone’s blood pressure rise unnecessarily we’ve had a chat to the DF Rules committee as it is currently and they have issued the following Rule interpretation for everyone to digest. The interpretation will also apply to the DF65 rules and more definition of what constitutes a legal repair will be detailed in upcoming rule revisions.

I don’t need to say any more than this, the rules committee statement below speaks for itself.

” The DF Rules committee have been made aware of a published interpretation by the American DF95 Executive of Rule A.7 ‘Repairs’ in the current DF95 Class Rules (Version 1.2). Their interpretation was never presented to the rules committee and does not reflect the original intention of the rule.

It is evident that in a minority of hulls there is an issue of cracking around the keel box, this is most likely due to inertia of the keel bulb during a collision or rough handling of the boat. In some instances it may be due to variations during the manufacturing process resulting in a thinner skin in this area. Rule A.7 allows for repairs to be made “provided they are not intended to enhance the original function or performance of the damaged items”. The Rules Committee and the rules author consider that a localised, internal repair around the base of the keel box is acceptable and will not enhance performance or change the original function of the hull. However, if the repair extends beyond this area or introduces additional structure, such as stiffening ribs or bulkheads, then it would clearly be a breach of rules A.5, A.6 & A.7.

Joysway have made several modifications to the moulding process to try and rectify this issue and are working with the designers on new ways to overcome this issue. In the next versions of the class rules, which will be published shortly, we will try to clarify the extent of what is considered a legitimate repair to the keel box area and there will be no time limit placed on the life of such a repair. In most class rules repairs are allowed, the DF classes should be no different provided they comply with any definitions in the class rules. Replacement hulls are available at a very reasonable cost but we feel that an owner should have the option to undertake a class legal repair and continue sailing their boat.

John Tushingham

Requesting an Interpretation

The DF ICA Regulations document outlines the process for requesting a rules interpretation. Head to section 9 and check out section 9.1.1 which gives you the correct way to get in touch with the Rules Sub-Committee and also tells you how your enquiry will be dealt with. It does not give you a timescale, however it might be reasonable for the sub-committee to meet once a month and issue interpretations as they are made.

The usual route to the Rules Sub-committee is in the first instance via your country body, secretary, or world-council member (NCA, DNM NCA, or NCS), who will then follow the procedure set out in the regulations to request an interpretation.

Section 9.2 is for emergency use only and is very much at the discretion of the committee as to whether they accept your personal approach to them. An appropriate example may be the need for a quick clarification during a major event.

%d bloggers like this: