‘Masts that fail in buckling are tremendously exciting with a great deal of carnage, but buckling is quite hard to accurately model. Avoiding it puts a lot of strain on the laminate and relies on super-accurate construction to achieve the buckling properties required.’ In a facility where precision was already a high priority, this project demanded a further step up throughout the manufacturing process. First up, normal practice would have been to use a standard aluminium mast section as a mandrel. However, off-the-shelf section shapes were considered too flat in the side walls, raising the buckling risk. Instead, a rounder 200mm section was designed and a custom mandrel built in a mould machined on C-Tech’s new five-axis CNC machine. Throughout the process, from the handling, storage and application of materials, to the temperature and pressure of the autoclave cure, extreme protocols were observed.
‘We took every possible
precaution,’ says Willetts. ‘We used ultra-high modulus carbon for a start and then took every possible step to absolutely maximise the known properties of the prepreg and epoxy. We were acutely aware that with zero safety margin even a tiny mistake in the manufacturing process could compromise the mast. Everything had to be as close to 100 per cent as we could make it.’
In the interest of pushing weight boundaries, some of the fittings were custom 3D printed in titanium. Even the normal finishing system was discarded and the mast was just sprayed with black undercoat for UV protection.
Similar debates surrounded the boom. Jundt wanted a boom weighing no more than 4kg. C-Tech’s first iteration was at 10kg and the final compromise came out at 6kg.
Top: the QFX hull in build. Lots of
builders like to say they save every possible gram of
weight; with this boat they really mean it. And yet the QFX’s owner, civil engineer Thomas Junt, still maintains that it’s a bit too heavy and unnecessarily strong. Right: if the rig looks
rather similar to one you’d find on a Sydney Harbour 18ft skiff, it’s no
accident. Spar builder C-Tech made its name on the skiff
sailing circuit and was chosen for this project for that
reason. That said, the QFX project pushed
C-Tech well outside of its comfort zone in terms of weight saving. The boom weighs less than 4kg and many of the fittings were 3D printed in titanium
Despite their “creative differences”, Jundt says he enjoyed working with Willetts. ‘It was great. I sent him an email to say I still think it is too strong, but he did beautiful work and the detailing is fantastic. I was very happy with C-Tech.’ The feeling is mutual. ‘It was a nightmare and a pleasure, which is exactly what you want,’ Willetts says of the project which drove the company to extremes. ‘This kind of project is the most exciting and
rewarding part of being a mastmaker, by miles. It is gold for what you learn from it.’
Having taken delivery of the mast and boom, Jundt and his crew wasted no time in hitting the water. Without the foils, which will be completed over the winter, they competed in the Centomiglia and Trofeo Goria races on Lake Garda in September, finishing second monohull out of 100 yachts in the first and fourth in the second. The Centomiglia breeze
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