RS:X ‘FinFix’ Working Party’s Report

The RS:X Class, following its AGM in Aarhus, have been working with Cobra to determine a solution to the issues experienced with the 66cm fins in 2018. These issues were a lack of reliability and concerns around consistency.

A number of potential solutions were discussed, with the decision to support the existing manufacturer identified as the focus for the class whilst retaining the option of changing supplier if a working solution was not presented. Cobra were given the clear brief of proving themselves to the class by suppling reliable, consistent and value for money fins. In addition, any new fin needed to sit within the existing manufacturing tolerances such that a rule change should not be required to limit fins.

Cobra reviewed the fin design, construction and manufacturing environment and made a number of changes to support the design brief. This changes included changing the layup and materials, refining the resin used within the fin and moving the manufacturing process into an air-conditioned room to decrease the effects of temperature and humidity on the moulds, materials and resins.

Cobra produced 20 fins to the new specification and three teams were asked to test the fins – each team being sent six fins each for testing with two fins kept in reserve. Great Britain, Poland and France were sent fins for the initial testing and a closed WhatsApp group was created to give direct feedback to the working party and to Cobra and Neil Pryde representatives.

Feedback was initially requested on the reliability issue, with all teams reporting that no fin was found to have developed cracks or bubbles and all were found to be structurally sound. This was the case even at the end of the testing period with teams putting up to 40 hours on the fins in planning conditions. This was felt to be a significant improvement on every past production fin produced.

Feedback then moved to consistency concerns. Teams reported that there were still differences between the fins in terms of performance and that these were still a concern. The test data from the factory showed that the fins were closer together in tolerance than previous fin editions (with two exceptions) and that this also raised a concern with how to effectively measure on water consistency versus factory data.

The report to the Executive noted that the situation with regards to reliability looked to be solved. Concerns around consistency should be addressed via a factory audit in early January where the RS:X Class will send Bas Edmonds, the Class Chief Measurer, to oversee the production of the fins along with a NeilPryde representative. As such, the Executive Committee were asked to authorise the production of the amended 66cm fin. There were no proposals to amend the 60cm fin at this time.

It is the intention that Cobra will start production of the new fins and that delivery of the first run will be delivered directly to Miami for the Sailing World Cup. The RS:X Class have been recommended to oversee the distribution of fins to ensure that this is done fairly with respect to those sailors who need the fins the most as a priority.

Bas Edmonds
Chairman of the Working Party
Chief Measurer of the RS:X Class


During its meeting on 17th December, the Executive Committee of International RS:X Class decided to approve the positive results from the RS:X 66cm fin testing group and from the working party and advised the manufacturer to start the production as soon as possible.

Regarding the eligibility of the fins – all so called ‘Black’ fins, including the latest ‘fixed’ version of it, are called Mark 3 (Mk 3) fins and are eligible to use at RS:X events.

The Class Executive Committee is expressing a great thanks to the working party, leaded by Bas Edmonds and the testing teams for their great contribution and help to solve the issue with the 66 cm fins.

Thank you!

Executive Committee
International RS:X Class Association

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