The RS900 - 'our' fantasy dinghy!

GRF
Building in luff curve to preload a mast is fine on a flexible mast that will
be supporting a sail that's going to be flat and then then flattened even
more by monster amounts of downhaul. But you're not going to be
murdering your downhaul in classes like the phantom and the osprey and
so you're not going to use luff curve to induce mast bend otherwise the
leech would be hooked in a big big way!! In fact the carbon masts used
on the slower dinghies are so damn stiff (compared to windsurfing rigs)
you're not actually going to be able to induce mast bend, you'll just put
abnormal amount of fullness into the sail, again hooking the leech in an
unsightly way.
And so you're right, you could say we're not making full advantage of
carbon rigs. But in boats that work on weight:power ratio's (slow heavy
boats) rather than power:drag ratio's (int moths), rigs like windsurfing
rigs simply won't do the job....... or at least no one's tried...???

Doug H

p.s I'm more than happy to stand corrected

Edited by Doug.H

I can't believe there is still a debate even, what year is it? 2008.

I hate to bring the W word in here, but we gave up alloy donkeys years
ago.

Not even cheap set ups use it, bar a few kids rigs.

Response, stiffness, weight, lack of corrosion, all way outweigh any
percieved alloy advantage, it still gets used on cheap booms, but purely
in a recreational capacity.

The only thing I actually wonder though, have sail designers actually re-
designed luff curves to take advantage of its qualities. Doesn't sound like
it in some classes, in which case you will get little advantage and
occasional negatives.

The most benefit from Carbon must obviously be on unstayed rigs where
its return to centre and minimal sail deformation in gusts is its primary
advantage of you ignore the weight. (Quite often to ensure it doesn't
break, carbon has to be mixed with glass, to ensure no interfibre
abrasion.

But unless you cut the sail to pretension the mast, it's not going to be
loaded enough to perform to its full advantage, I doubt that happens in
classes that mix both, so they wont get full advantage.

long ally masts are dangerous i think. This is probably due to me normally sailing the 14 (hull no 1318, an old one) with only about 150-160kg on board, so when we do go for a swim we barely have the righting moment to get the boat back upright in flat water with both of us right on the tip of the daggerboard, let alone in solent chop and solid F4. However if the mast was sealed there wouldn't be so much of a problem. As for gust responsiveness, i suppose i should be able to compare the 14 and the 600 but i spend so much time just trying to keep the 14 upright i don't really notice gust response that much, on the 600 though you definately notice the tip twitching and dumping power in gusty northerlies.

Didn't Ian Walker win the 14 champs with an alloy mast when everyone else had switched to carbon?

Mind you, don't suppose he did much righting  . Also, you don't get so many gusts sea-sailing, of course.

Perhaps this is the answer.  14ft, asymmetric, 2 sliding seats (crew's is 10ft and helm's is 8ft) - so plenty of leaverage!  Its called a Skate, does anybody know more about it?  I emailed the Class Sec but the message bounced.  This picture was taken in November this year on the Swan River, WA.