Ok, Ok, so I accept I can't use my old fibreglass mast anymore, but how much carbon do I need. Prices go from $300 to $10,000,000 depending on the carbon content. Where does the benifit drop off? Okay to stick with the 30% cheapies, or do I need 50%, or 90 or 100%.

Thanks,
Harrow.

30% cheapies are fine, it depends what you want to use them for. If you were starting out wave sailing or were hard on your gear then I would suggest a 30% cheapy. Weight is a little heavier but if you're coming from fibreglass then you'll think these are awesome anyway.

At the other end 100% are fine but I am hard pushed to see any performance benefit from them (over a 75%)aside from weight.

Considering weight, longevity, money and response rate, I would suggest for general sailing:
for masts 430cm and smaller 30% or similar (45)
for masts 460cm and bigger 75%

I have a theoretical problem with 30% carbon. From experience it's not good to mix materials of different stiffness, in a load bearing situation. The stiffer stuff takes all the load, the less stiff stuff just adds weight, without adding any strength.
All fibres in tension should be carbon, those in compression don't matter much, fiberglass and carbon have similar compression characteristics. I have 70% carbon masts that are about 10 years old, have jammed them into the reef with sailboard dangling in the air out of reach, have fiberglassed the wear in the boom clamp area from the amount of use they've had, still going strong. These masts have all longitudinal fibers carbon, glass around the circumference.
I've no practical experience with 30% carbon masts, so can't really coment on them.

SDM, RDM???

I get the feeling this is a payback for my FWS post.

quote:

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Originally posted by Northboy

Standard Diameter Mast and Reduced Diameter Mast.

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hey! Anyone tried filling their mast with helium?! Imagine how light it would be!

sorry couldn't resist, i been reading too much of the kite forum lately