Top: the downward curve at the back of the wings on the new boat assists in funnelling airflow away from the centre of the boat in an effort to translate some of the aero drag into forward drive. The wing bars for the Mach 2.6 do away with compression struts and so for existing boats (left) being upgraded extra reinforcement is necessary by means of this simple carbon plate. Mach 2.5 (centre) and 2.6 (right) – a great deal of effort went into reducing drag in the flight controls as well as making them cleaner and easier to operate
Mach 2 days, but it is a complex area… He was playing with bowsprits for a
long time and had two Moths, one with and one without, and sailed with the one without as he couldn’t see the gains in the bowsprit. Then he put the four-bar linkage on to get the reactions that he wanted and the bowsprit boat came to life. That was a while back but the overall
revamp for the 2.6 simplified it all. The Mach 2.4 bowsprit was complex, not particularly robust, and with quite a bit of friction, and so for the Mach 2.6 they have eliminated half of the linkages, got rid of the sliding bits and taken out any slop, meaning that it is now both very low friction and very reliable. People have remarked that the change
from the 2.4 to the 2.6 bowsprit is the best upgrade they have ever done as the boat just comes to life again. So this makeover number six of the
Mach 2 was nothing radical, just thinking hard through all the mechanics of it all and making it all work properly. The boat is indeed now exceptionally reli-
able due to these micro upgrades. As soon as a weak point was identified they worked
52 SEAHORSE
through that and improved it. A boat may have been five years old when something broke on it – but why did that happen, and can they do it differently? It may be just an extra strip of carbon on the centre of the foredeck, or a piece fitted under the wing bars at the back, or going from a 2.5mm rod to a 3mm rod, but just doing it wherever they saw it improved the overall picture. The boat is possibly 3kg heavier than when the revamp started… but it is now bulletproof. The hull has been strengthened while
the deck layout was refined through the previous upgrades, moving all the cleating out closer to the sailor. This gets rid of much of the drag from various lines, so you don’t have anything like the vang or cunningham going anywhere but a short distance next to you… all very clean.
Foils
McDougall covers the key part. ‘Multiple foil sets are hugely expensive for sailors coming into the Moth class, often from the Waszps where everything is super simple. ‘Instead we wanted to push towards
making a set of foils that are going to both suit everyone plus work in every condition,
and I really think we have done that. ‘In particular we have changed a lot in
the way we deal with torsional rigidity. For our purposes torsional rigidity is much more important than flex rigidity – particu- larly on the front (main) foil, where if you get any torsional flex you can get vibra- tions that cause all sorts of drag. At the same time we have a longer span and we are going faster now and often the tip is out of the water, which is another big factor. ‘Because we have a long span and I
didn’t want longer verticals we had to make it so that the tips could come out. We went through a few iterations on that… We had tip-down foils which we found really poor as you get a double breaking of the surface, where the tips are still in the water but the rounded section is out and that creates lots of drag and ventilation. ‘We also spent a lot of time working on
how to neutralise all the pressures around the tip. Like the sail, the tip is there to make the rest of the foil work and not to be too pressured so you get ventilation coming down. ‘So we wanted to sail this boat with the tip out of the water – that was a big factor
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