Structural failure caused La Trinitaine-Team Ethypharm's bow breakage

Designer Nigel Irens issues a statement

Wednesday May 16th 2001, Author: Nigel Irens/James Boyd, Location: United Kingdom
Nigel Irens, designer of La Trinitaine-Team Ethypharm, has issued a statement about why the crash box on her port bow broke:
La Trinitaine - Team Ethypharm has been severely - perhaps fatally - damaged as a direct result of a structural failure of the bow of one the new floats that were fitted new for this season.

The bows of all the trimarans in the 60 ft ORMA fleet are fitted with a 'crash box' which is sacrificial and is intended to absorb the impact of collision with floating objects, leaving the rest of the structure intact. It is not yet known in this case if the float was subject to such impact or not.

It has now become known that the bows of La Trinitaine - Team Ethypharm were built to a design produced by the building yard, Tresco, and not to the design issued jointly by Nigel Irens Design and structural engineers High Modulus Ltd.

Nigel Irens Design was not made aware of a number of important changes that were made to the original design, which is based on well-established and proven principles. In our opinion the replacement design is flawed and fails to meet the design criteria on a number of counts.

It is known that the bows of the other floats produced respectively for Fujifilm and Sergio Tacchini (two other trimarans Nigel Irens has designed recently) from the same mould and by the same builder were built in accordance with the original design.

Nigel Irens Design generally respects the competence and quality of work produced by the builder, and can only assume that this situation has arisen as the result of an isolated aberration."

It seems from this that the bow breakage on La Trinitaine-Team Ethypharm may not have been caused by colliding with a submerged object, but just from the sea. In the past years there have been several instances of trimarans losing their floats in this way. They have become less and less frequent as designers and engineers understand more about the loads involved. But Nigel Irens is saying that in this case it was the crash box itself that was built incorrectly.

The tip of a trimaran float's bow is usually made of block foam and around 400mm back from the bow is the crash bulkhead. This is the main structural bulkhead at the front end of the float. In the event of a collision the block foam bow is supposed to snap off leaving the crash bulkhead and float intact. This did not appear to have happened with Marc Guillemot's stricken trimaran...

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