Salutary experience. Clear evidence of the need for sheet fuse or always attended quick sheet release. If self tailing and hydraulic winches are used, the system could be double ended with quick release. That said, I haven't seen a cogent discussion of the contribution of the foils.
What's been lacking is a discussion of the weather helm that resulted from, firstly heel (rig CE shifting to lee) and secondly (release of head sail sheet). Attempts to counter this weather helm appears to have resulted in cavitation at the rudder. Combined with the higher that normal ride height (due to wind and possibly sea state) this rudder cavitation resulted in loss of lift. The stern dropped, increasing the angle of attack of the main foil.
As discussed elsewhere, when the craft came off the foils, it slowed dramatically, increasing the AOA, necessitating an even greater main sheet release. The foil stall seems to have contributed to this slow down.
I've never been a fan of this foil configuration for offshore craft. The foils are necessarily fairly close together which will present pitch problems in sea states that cause wave profiling, and as seen here accentuate pitch when cavitation occurs.
The cat rigged proa is unsuited to this configuration unless weight can be shifted aft - the CE shifts aft with each shunt - feasible on a small craft only. With canard steering, the lateral resistance foil can be further aft (aft of the centre of mass) with the canard providing balancing lift and a longer foil base. C-fly is the leading example of this concept.
David - Drawn Onward
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Posted by: cruisingfoiler@yahoo.com.au
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