IMOCA one design parts soon to be tested

Masts, keels and canting mechanisms are standardised on the latest boats

Two years ago, the IMOCA class made the decision that in an attempt to contain costs new boats would be fitted with one design masts and keels. This choice was made allowing the class to take the middle ground between a fully open rule and a fully one-design boat.

Two years on, with several new IMOCA 60s in build, the first one design parts are being integrated into the boats. Their design and manufacture has been entrusted to approved suppliers, who are all specialists in their field and fully acquainted with the requirements of IMOCA 60s.

IMOCA is breaking new ground by introducing one design elements to prototype race boats. After consulting with technicians, skippers, designers and approved suppliers, the Class has made the change with the following aims

- To remain at the highest level of technology, as standardisation is not about dumbing down;
- To be capable of supplying identical parts to guarantee complete equality between boats;
- To ensure one design integrity through strict monitoring of manufacturing procedures and controls.

Based in Lorient, southwest Brittany, Lorima is responsible for manufacturing the masts. The first spar is about to be delivered to Team Safran for Morgan Lagravière’s new monohull ready for her christening this weekend.

For the Lorient-based company, it has been a major challenge as Vincent Marsaudon, Director of Lorima, explains: “We really need to guarantee total equality between the teams by supplying them with identical masts. To achieve this, we’ve put in place some stringent quality control procedures. In the lay-up, we’re capable of providing original samples of all the materials used. Following that we carry out ultrasound tests and stiffness tests, in the knowledge that all the masts have to weigh the same…”

This specification was agreed between the IMOCA Class’ Technical Committee, which initially worked in collaboration with Denis Gléhen, who is in charge of the mast design.

During manufacture a quality control record for each mast is created and this will form the information base, enabling an ‘IMOCA Conformity Agreement’ for the mast to be issued subsequently.

“The final control checks are done in the presence of the class’ Chief Measurer, who validates the work carried out. Furthermore, we have an electronic chip which will effectively become the mast’s memory,” continues Marsaudon. The first test, in just a few days’ time, will be for Safran's new mast.

These same principles guided IMOCA in choosing its suppliers for the boat’s one design keel. AMPM is not new to working with IMOCA teams: The Vendée-based company has already manufactured numerous fabricated IMOCA 60 keels as well as the first keel fin machined from a solid billet of steel for Vincent Riou’s PRB in 2006.

The new one design keels are the fruit of a close relationship between Sébastien Guého of Hervé Devaux Structures (HDS), who engineered the keel and AMPM, which is providing its manufacturing expertise. As with the masts, so with the keels there is the same scrupulous execution and a desire to ensure all the teams have identical equipment.

“Basically, we start out from the same block of material. We check the mechanical quality of the material by carrying out extensive chemical analysis to guarantee this. After that, all the parts are machined exactly according to design drawings, supplied to us by HDS. After machining, we check the part to ensure they match the design drawings and we weigh it – the variation must be less than 3kg on a part that weighs in at around 950kg – and we move it to the bench to carry out a bending test, where 3.1T is applied at its tip (the maximum weight of the bulb).”

Then the keel’s trailing edge is fitted, once again with scrupulous care to ensure its one design conformity. As with the masts, the IMOCA class’ Chief Measurer then checks all these parts, and certifies a quality control record, which AMPM is responsible for completing.

Under the new IMOCA rule, the keel's hydraulic canting mechanism is also one design. Manufacturer of this was entrusted to Hydroem, based near La Rochelle, it too having worked on system fitted to IMOCA 60s for many years. The company has brought all its experience to bear in the design and manufacture a reliable and high performance system for the new boats.

IMOCA is now entering into the application phase with its new rule, which will remain unchanged until the end of the 2016-2017 Vendée Globe. With new standards and new constraints for both teams and designers, time to adapt is bound to be necessary to allow the new rules to be integrated as smoothly as possible. However, the precision of the specifications and the desire by the manufacturers to comply with these stringent quality standards are the best guarantee of success in the switch to these one design parts for these two particularly vital areas of IMOCA 60 monohulls.