Technology


Yannick Eudeline’s Mini 6.50 is designed and engineered to be built in epoxy-plywood composite with extensive use of natural fibre materials. Note the chamfered arrow bow profile


eco-friendly epoxy resin, an ambitious plan to design and build a next-generation range of low-carbon offshore racing yachts was gathering pace. There couldn't be a better proving ground for the new Greenpoxy 550 – a bio-based resin system designed specifically for hand lamination of timber-and-fibre composites – than the Greenscow initiative, which aims to demonstrate that plywood is a viable hull construction material for Mini 6.50s, Class40s and Imoca 60s. You might be inclined to dismiss the


whole idea of plywood grand prix raceboats as a foolish, futile endeavour but it’s a credible proposition. Plywood has great potential as a core material – it’s stronger than foam and in sandwich construction, with two skins of fibre, it can be just as light and stiff. It also has a much lower carbon footprint than other core materials if the timber is sourced from renewable forestry, and it’s very efficient for one-offs and small-series production because you don’t need to make a mould to build the boat. The Greenscow concept comes from


Gildas Plessis, a naval architect whose 350 designs range from dinghies and workboats via offshore racing monohulls


66 SEAHORSE


The future is plywood T


he timing was perfect. Just as Sicomin completed a long- running R&D process to replace one of its keystone product lines with a brand new


and big cruising multihulls to megayachts up to 120m in length. When the French Sailing Federation set a requirement in 2023 for all yacht racing classes to get ready for a major reduction in the carbon footprint of new boats, in line with the 2015 Paris Agreement, Plessis designed a low-carbon Class40. Epoxy-ply composite construction is one


key element of the Greenscow concept; another is replacing as much carbon as possible with natural fibre such as flax or basalt. Sicomin’s bio-sourced Greenpoxy resins also lower the carbon footprint of building the hull and are much less toxic than most comparable epoxies. Compared to a full carbon composite hull, the overall footprint of construction can be reduced by up to 80 per cent. No natural fibre material can match the strength-to-weight ratio of carbon fibre, but a natural fibre composite (NFC) hull can be competitive in Class40 and Class Mini, where the use of carbon is limited. While carbon fibre is essential for some components such as foils, an NFC hull is feasible even for an Imoca if allowances can be made for the difference in weight – and with a carbon cap for Imocas now looming, NFCs offer an alternative. Several Class40 skippers are raising


funds to build a Greenscow 40 and a cruiser-racer version is already in build. A veteran Imoca skipper, Marc Thiercelin, has also bought into the concept and a


Sicomin has completely reformulated one of its original resin systems – and it’s now being used to build a new generation of low-carbon racing yachts


60ft foiling Greenscow has been designed and fully engineered, to be built for the 2032 Vendée Globe. In the meantime Yannick Eudeline, a young naval architect and former aerospace engineer who works in Plessis’s design office, developed his own Mini 6.50 Greenscow design in his spare time and hatched a plan to build and race it himself. ‘We noticed that the smaller the boat,


the smaller the proportional difference in weight between a carbon composite and NFC hull,’ Eudeline explains. ‘For the Greenscow 650 we are aiming for a variation of around 50kg. Being prepared to lose a little performance on paper is part of our approach to implementing a different build process for racing boats. ‘I say on paper because, as I see it,


the disparity in strategy or skills from one skipper to another is more impactful than a few extra kilos. In terms of stiffness there is no real difference because we design the boat to withstand the same loads. As the material is not the same, the overall layout of the boat's structure has to be adapted to use the right fibre in the right place.’ A fully equipped Greenscow 6.50 will


weigh less than 800kg and Eudeline’s design has some interesting features. ‘The idea was to design a scow with a wide, spatula-shaped bow and a lot of rocker but the round-nosed boats that exist today are difficult to imitate with


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