Zero tolerance
One company leading the revolution is Persico. Over the last decade Persico have become one of the world’s leaders in raceboat production. At present they are nearing completion of the new Mark Mills-designed WallyCento, while also this year starting a new 144ft fast cruising yacht, set to be built at their new facility in Massa Carrara, near La Spezia.
Twenty-seven years on from the company’s launch and there are CNC milling machines wherever you look in Persico’s gleaming new facility. However, now those CNC machines have been joined by some of the most sophisticated and up-to-date composite manufacturing equipment that you are likely to find anywhere outside Boeing or Airbus…
Along with a generously sized ISO 8 clean room (opposite), Persico now boast their own in-house ultrasound scanning system for non-destructive testing (NDT), a large-scale 3D scanner for both reverse engineering and the dimensional scanning of
44 SEAHORSE
A quiet revolution has taken place in composite boatbuilding over the last decade which is being reflected in the ever more precise build of the best raceboats – from America’s Cup to offshore Maxi Above:
components, four different fixed ovens, the largest being 45m x 12m, plus a transportable modular oven and a 25m x 8m vacuum table to join the two other existing (large) tables.
America’s Cup
For the America’s Cup Persico worked with Luna Rossa in San Francisco and with Land Rover BAR this time. The company has built around 80 per cent of the British AC50, including the tooling for the hulls (but not the hulls
themselves). This included by far the trickiest parts – the foils and the wings, both at the limit of what is currently possible to build, albeit for entirely different reasons. AC50 boards, for example, are either two-piece with a metal or composite part forming the core of the corner, enabling each shaft to have different tips attached to it. AC foil designers push for the smallest section foils possible to minimise drag within each wind speed range, while at the same time requiring exact deformation
having been christened Rita – no big surprise there – Land Rover BAR’s ACC race boat goes afloat in Bermuda. As the first project in their new facility (opposite) Persico were responsible for most of Ben Ainslie’s newest steed, including the wings and foils plus the tooling for the hulls, at least the front
25 per cent of which must be built in the country of challenge under the
2017 Protocol
characteristics, all from a part that will often be carrying most of the weight of the boat and the dynamic loads encountered at 40kt+ speeds.
Yet the foils are structured with next to no safety margin – only possible today because of the accuracy of FEA and subsequent manufacture. As Somerville says: ‘It’s amazing: it wasn’t that many years ago when you just didn’t understand exactly what the safety margin was. In 2017 we’re engineering it down to the last few per cent. It puts a huge emphasis on the manufacture.
‘These boats and parts must all now be absolutely flawless.’ Persico have acquired huge experience in building foils, be it for monohulls such as Imoca 60s or for flying multihulls such as the AC45 turbos, AC72s and the latest AC50s. As a result they generally end up co-engineering the boards for these types of boats. Nonetheless, building AC50 boards still takes months, involving a complex process that is half-laminating and half-machining. ‘You’re laminating inside moulds, then you’re curing, processing and assembling parts within the tool and going in and out of milling machines between three and five times to produce a daggerboard,’ explains Somerville. Typically they lay up the (inner) compression side of the board into a mould and machine the (outer) tension side. Being able to do this while
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