Rules Interpretations

This page details the interpretations made by the rules committee.

DF Classes Rules Interpretation September 2024

The following three questions were raised via the French DF95 Class Association:

Question 1: Is it possible to assemble the jib luff tabling pocket for the forestay by sewing or/and double sided tape and sewing?

Answer: Yes.

Reason: “Tabling” is defined in ERS (G.6.3), and the DF measurement committee supports this definition. A fold and sewing are covered under this definition. However, the fold dimensions must fit within the 12mm band defined in the class rules. It should be noted that while sewing may be appropriate for woven cloth, it is generally not recommended for monofilm due to the potential for reduced integrity and added complexity from the holes. The rules committee may consider revising future rules to prohibit the sewing of monofilm to guide participants towards a good solution.

Question 2: Is it possible to apply a reinforcement patch with double sided tape? If yes, does the double sided tape count as one layer?

Answer: No. Material and double sided tape is not allowed for reinforcement patches.

Reason: The Class rules reference “self adhesive material”. The class rules call for the use of commonly available self adhesive material that may be quickly cut and applied. This has been selected to simplify sail construction. Using extra layers and parts moves away from this goal.

Question 3: Is it possible to reinforce the mainsail luff attachment point with a little piece of wire inside the patch?

Answer: No.

Reason: Metal may optionally be used for sail reinforcement but only when used as an “Eyelet”. Eyelets are round. Although the method explained is an elegant method, as the rules are currently written, it’s not allowed. It should be noted that most aftermarket sails are constructed today without metal eyelets along the luff midpoint position. A reinforced hole without an eyelet usually suffices, and also reduces construction time and cost.

DF Classes Rules Interpretation April 2024

Q: The DF Class rules show a mainsail convex luff curve in the supporting measurement diagram in Diagram 3/A. Is a concave luff curve allowed under the class rules?

A: No, a concave luff curve is not allowed under the DF65 and DF95 class rules. The class diagrams for DF65 (Diagram 3) and DF95 (Diagram A) specifically illustrate the mainsail luff measurement points B through F as positioned forward of a direct line from point A (Tack) to point G (Head). This arrangement mandates a convex luff curve, which is the only permissible curve shape according to our class rules.

Adhering to Section A.5, “Spirit of the Rules,” participants are expected to follow these specifications to ensure boats are raced on a level performance basis and costs are kept under control. The introduction of a concave luff curve would not only contradict the rule’s requirements but also take the design away from the majority of stock sails supplied with the boats and sails currently used across global fleets, potentially offering a performance difference and disrupting the uniformity intended by the class rules.

Effective Date: This interpretation is effective from 15th April 2024.

Issued by: DF Rules Committee