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FOILS - Basic Explanation

Foils or daggerboards were initially devices to prevent the boat slipping sideways when going upwind.  It was discovered that they could also have an effect when going downwind too, rather than just being retracted for drag reduction purposes.  By varying the shape and section of these foils, the boat could initially be made to ride higher in the water to reduce drag more. It was then found that they could be shaped and manufactured in such a way as to actually lift the whole hull completely from the water, with a corresponding dramatic increase in speed.  Sailing techniques, together with new foil shapes and sections, have developed so that this can even be achieved going upwind in certain conditions.



Foil controls -  Many sailors were intrigued by the 'knitting machine' that was underneath Stevie Brewin and Adam Beattie's Exploder Ad3 trampolines.  So, here is an annotated photo to show what does what.  The undertramp mainsheet cascade system was not actually used in the racing, so you can ignore that bit.  The added apparent complexity is just ingenious use of the takeaway bungees to allow a clear deck, the holy grail of 'A' cat systems. 

Many thanks to Stevie for sharing his secrets.