Statement on the use of Ultra High Modulus Carbon in masts

Following recent developments in the Finn Class, the OK Dinghy Class may soon be faced with the prospect of Ultra High Modulas carbon being used in their masts and the increased costs that go with it. This is a situtaion that the Technical Commitee feels would be bad for the OK Class and also for the mast manufacturers.

The Technical Committee has been working for some time to find ways to stop this.
A year or so ago the OK Dinghy Class approved a rule change to ban the use of carbon with a modulus higher than 400GPa in their masts. This rule was proposed to ISAF, which subsequently rejected it on the basis that it is unenforceable because only destructive testing could be used to check what is in a mast and they felt that this would be unacceptable to the sailors.

ISAF suggested that the only way forward was to introduce a scheme of licenced builders. We are now working with ISAF and looking at ways to acheive this. We realise that this would be a big change for the Class but feel that it is the only option. However, any Rule change must first be passed by the AGM and then ratified by ISAF.

At the time that the Rule change was rejected by ISAF, the infomation we had recieved from various experts was that UHM would not work in unstayed masts because it was too brittle. But as just mentioned, recent developments from the Finn Class have outdated this infomation.

As a class, we feel that it is beneficial, both to the Class and the mast manufacturers not to use UHM, and so we would ask everyone to please refrain from using it until we can get Rules in place to ban it. If and when this Rule change is passed, the intention is that all masts must conform, whether built before or after the Rule change. We feel that expensive masts, and in fact any developments that allow a few sailors to gain an advantage at large cost, are bad for the future of any class and their gear suppliers.

Thanks you for your cooperation and please let me know if you have any comments or thoughts.

Alistair Deaves
Chairman – International OK Dinghy Technical Committee