Above: an early iteration of what became the Mach 2.6 (right) being tested on Lake Garda – once again by Andrew McDougall himself. However, once there were more forerunners for the new boat in Europe other top foiler sailors were brought into the test programme
better finesse individual batten rotation. This involved a huge amount of trial and error, to identify which battens need a full rotation, which needed limited rotations – with some requiring no rotation at all instead leaving the batten locked into the cam. Refining this and getting it right was a big part of making the 2.6 rig work well across a full range of conditions.
Wing bars Wing bars have been gestating for a number of years in the class. Three years ago a lot of CFD work was done on the Mach 2 hull and after that McDougall had a clearer picture of what he wanted the air- flow to do over his next Mach 2 model. And then he had his epiphany… ‘If I curve one wing bar this way and the
other one the other way I get everything I want. I pull the front of the wing tramp up, I get the leading-edge curvature and I am getting the wind to be exhausting out of the side of the wing bars, rather than it funnelling back into the centre of the boat where life becomes very draggy.’ It wasn’t quite the epiphany that saw Archimedes sprinting around Syracuse naked shouting ‘eureka’ but I could hear the energy in McDougall’s voice confirm- ing this was a big deal. He built new wing bars in late 2019 to go to the Australian Nationals, but broke them three times in testing before that… He’d always planned to fly up to the
event but ended up having to drive as he simply ran out of time; however, this Edis- onian approach of constantly trying and failing resulted in his own lightbulb moment. ‘It was just a rocket ship. The very first time I got on it I knew it was as big a gain as the deck-sweeper, as suddenly I was going higher and faster! ‘The whole rationale behind the wing
bars is to get flow underneath the wing, to exhaust the flow nicely out of the back of the wing bar rather than it being a break at that point. All of this reduces drag and
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gives you downforce and so what happens is the wing becomes the sail.’ A little slow to grasp this, I asked him to expand… ‘You have a horizontal foil, which is the
wing, and so you are squeezing the boat forward like an orange pip… This is mainly on the leeward wing bar, as the windward one isn’t doing so much. ‘People ask if it is giving us lift – no, it
provides downforce. When you are going really fast you have downforce opposing the foil and so you can run with a bigger foil and it doesn’t get out of its drag bucket. The first time I sailed with that configuration, I thought, “Gee, I am going high and fast, what do the numbers say… and what will it say after I have tacked?” and again it was high and fast…’ High and fast; faster through the water
even in high mode, music to the ears of any Moth sailor. The other upside of the wing bar development is they had previously added a cowling over the boat to com- pletely close the gap between the sail and the deck and this had brought some limit - ations with the control lines running through it; once they went to the new wing bars they discovered the cowling made zero difference. McDougall spent a lot of time sailing
around with tell-tales fitted all over the boat, plus one on the end of a rod which he waved about, positioning it in various spots while sailing the boat around with one hand, trying to picture where the flow was over the boat… a life-sized wind tunnel. He could clearly see there was no flow passing from windward to leeward at the bottom of the sail because they were now directing the pressures more efficiently. Even the shape of the hull, which is
almost 13 years old, they now regard as perfect as it brings all of these aspects together. What this means is the boat was probably the wrong shape 10 years ago. But now that they are going faster through the water and pointing higher,
better encapsulating the flow around the boat, they have the wind off the foredeck being directed into the sail, and so the fore- deck works, and the fine bow works. One of the things McDougall feared
was that they were losing flow around the bow, making it a huge drag area; not so… ‘You are now getting flow around it, because we are sailing so much higher and faster, and the apparent is so much further forward… and so the hull has suddenly also become a sail, rather than a spinnaker working the wrong way.’ Moving onto the tramps, the wing bars
are there to give these shape, and so the tramps have been redesigned to fit the wing bars; but they are still a flat sheet of cloth with pockets for the wing bars and so nothing has really changed there. And they have kept the bladders. McDougall again: ‘I can’t see why anyone would want to sail without bladders. It only takes one mistake and you have lost all your gains… really it is only a weight thing now. ‘And the bladders are encapsulated
within, there is no real aerodynamic loss, so a tiny bit of weight. But you have the ability to relax a little in between races!’
The meat And now we come to the technical parts on this makeover… the bowsprit, hull and foils. Bowsprit iterations really started before
even Mach 2. McDougall was keen to have the bowsprit set at the ‘fast point’, right where the most work is being done, where the wand is normally at a 35-40° angle to the vertical. As it moves backwards and forwards
the desire is for it to be less aggressive, and that has been difficult to achieve with the standard mechanism. So the options are a four-bar linkage – which the Mach 2 has – or a cam, which is what some of the other boats have. McDougall started working on the four-bar linkage back in the very early
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