Clockwise from above: the internals of the all-new bowsprit and gearing arrangement developed for the Mach 2.6. The pull rod is now directly connected to the ride height adjuster via the reversing lever that delivers the correct dynamics. The refined new arrangement sees a considerable reduction in friction and is also more robust than the previous configurations; the first production 2.6 is made ready for shipping; the bowsprit of the Mach 2.6 features this super-clean connection to the hull; as well as refining the flight control systems the mechanisms needed further adaption to accommodate a very low new deck-sweeper from McDougall’s own KA Sails loft
requiring major changes in the sections.’ Reflecting on his Moth improvements,
there have been three major epiphanies in his foil section development over the years. The first was the original Bladerider, the second was the Mach 2 and the third is Mach 2.6, and here is where the magic really kicks in, all of it directed towards achieving the widest possible optimised range. ‘Why we didn’t see this section being a
gain before was we are now with a smaller chord. And so suddenly the combination of the previous section but with a smaller chord meant the drag was starting to really bite, so we found a different section and started all over again. ‘With new sections what we have done
is compressed the speed [range] a little bit; by having a bigger foil you get back your low speed though obviously your high- speed drag is now higher, but critically it is not the top speed that you are searching for. For racing it is that 20-26kt range where you need drag to be really low. ‘So we said let’s throw away the 30kt
target and absolutely optimise everything from 15 to 26kt. That means this is one foil for everything, with the whole foil optimised for that speed bracket. ‘Frankly it is pretty hard to go faster
than 28kt and honestly that rarely wins races… sustained high speed is the goal. ‘So the new 2.6 front foil has the biggest
span of anyone’s, but with the smallest chord. The total area is a touch bigger than most of the other foils but the all-round ability of it is insane! And it makes the boat such a joy to sail…’
Making it Finally we come to manufacturing. With the main foil McDougall and his team have always created the hinge within the mould, so when they pull it out it just needs a quick clean-up and it is done – no further cutting or joining. However, they were already approach-
ing the limits of this technology with foam- filled foils and so, in conjunction with a composites specialist in western Australia, they developed a new construction method… one that brings both a com- pletely new way of creating the gap in the foil and a strict ban on me writing about their new technique in any more detail! For now at least. What I can say, however, is that with this
new manufacturing method the foil comes out of the mould absolutely pristine and ready for its soft packaging. The flap is also manufactured fully in place, in the foil, fully articulated with no work left to do. This has always been a tricky part of the boat to get perfect, not to mention the nerves when you commit to around $40,000 worth of tool- ing – plus we all know that foil flaps have derailed America’s Cup teams, with all their intellect and money… And finally with the rudder foil the
main thing is to try to disengage the verti- cal and the horizontal, so that the bulb is less critical. The bulb on the front foil is highly important because of the adjacent vertical and horizontal areas, meaning the pressure is multiplied by the two foils coming together, producing cavitation at that
intersection… which is why the bulb is there, to avoid draggy pressure discontinu- ities at that intersection. By contrast, on the rear foil the Mach 2.6 has the horiz - ontal foil stepped a long way back from the vertical foil, allowing for a reduction in the size of the bulb which in turn delivers a further reduction in drag.
All-round solution Amac’s latest package is strong, fast and reliable. Interestingly what has been the driver of all these little changes is a year of lockdown. With McDougall unable to travel to China for face-to-face meetings with his builders McConaghy, everything has needed to be drawn in even more detail than usual, then dimensioned and tested. This means that every component on the 2.6 fits perfectly first time with every other part regardless of manufac- turer, making sure your boat comes out of the box genuinely ready to rig and race. This past year has involved a lot of
drawing for Andrew McDougall then going sailing – and more drawing and going sailing… Carefully and methodically working through the issues, making sure it never breaks, is less drag and works straight out of the box. His goal was a new Moth capable of
finishing top-five in the worlds, yet priced well below some of the class’s most exotic alternative offerings. The perfect step-up from Waszp to Moth, or just to come into a new class with a fast and reliable but above all more all-round and more easily tuned package. Lock and load.
q SEAHORSE 53
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