I have a 5.0 Neil Pryde MkII World Cup Slalom sail, which I can't rig to
I am rigging it on a North 2-piece carbon race mast (or at least that is
what I am told it is: I bought the sail and mast from separate people at
the Windsurf Wherehouse swap meet in S.F. last Saturday). I think the mast
is carbon, because it is black, with black fibres running longitudinally
down the mast. Each piece of the mast is 220cm long, and it is almost a
perfect length for the sail.
My problem is that while I can get what I consider to be appropriate
camber in the lower half of the sail (i.e. the lower 3 cam'ed battens), I
think that the upper half (i.e. the upper 2 cam'ed battens and the top
uncam'ed batten) is way too flat, in fact the outer edges of these battens
almost have negative camber.
I have tried adjusting both the downhaul and outhaul: By adjusting the
outhaul, I can get a wide range of cambers in the lower 3 battens (from
deep to flat), but it has little effect on the upper 3. By adjusting the
downhaul, I can (as expected) make the leech looser (more downhaul) or
tighter (less downhaul) at the upper battens. The problem is, tightening
the downhaul makes the upper three battens very flat: with enough downhaul
the leech becomes very loose, and the upper 3 battens start to get
negative camber in the outer half of their length.
First, I don't like the negative camber, and second, even with a loose
leech, I would expect/like the sail to have an approximately constant
camber-to-chord ratio from foot to head. (This is how most of the sails I
see in the brochures and on the beach look.) Also, I would expect that I
could adjust this camber-to-chord ratio for light and strong wind
So, what am I doing wrong? Is it as I suspect that the top half of my mast
is not stiff enough? Unfortunately, I can no longer read the markings on
the mast. Is it possible that I got a stiff lower half and flexible upper
half? Or is there something else I am doing wrong?
Thanks for the advice.
Michael L. Eglington
Tel: (415) 497-2316