SP claims boatbuilding precedent
By IBI Magazine
Composites manufacturer SP has supplied a full system of composite materials including its new SE70 low temperature epoxy prepreg, for the construction of a unique IMS 54ft racing yacht.
SP has worked closely for many years with Richard Gillies, whose project portfolio includes Volvo Ocean Race winner, EF Language, and the IAAC boat, Oracle, runner up in the 2002/2003 Louis Vuitton Cup, both of which used SP materials and engineering services.
Traditional build techniques using male plugs and female moulds are suitable for many boats, but for the grand-prix boats, such as the IACC, these methods still incur additional weight and production time as they need to be extensively faired and painted to correct irregularities.
For small components, solid modelling and CNC machining a female tool from a solid block is now a common procedure. The advantage of CNC machining a female tool is the accuracy of the final part compared to the original design spec, and the almost perfect surface finish this creates. This technique has not been used on such large components, so the direct hull mould of this 54 footer, built in collaboration with the M Torres facilities in Spain with the company’s five-axis milling equipment, sets SP claims, a significant precedent in boatbuilding techniques.
The hull itself was then constructed using SP's SE70 low temperature cure epoxy prepreg. The low cure temperature meant it was suitable for Gillies' tool, offered lower thermal movement during the cure cycle, which in turn reduced distortion of the structure's shape. This ensured the boat remained true to its original design and geometry, and provided a near perfect direct surface finish which greatly contributed to the weight savings in the structure.
"We are overwhelmed by the almost perfect surface finish of this boat," says Gillies. "Absolute minimum fairing was required - in fact there was so little to do that we used a small artists brush to spot fair! We sprayed the boat with a clear coat in one-hit and the hull now has a reflective, mirrored surface."
(1 July 2004)