I am a hack weekend warrior and looking at a 430 cm mast for a 5.8mtr cammed sail. I am wondering whether I will notice any difference in the sails performance between carbon contents apart from weight?
Difference in cost "out weighs" the difference you would notice I would think...
I can't talk, I only have 30% carbon in my masts..... I just make sure I rig up quickly and pack up quickly so that no one knows my secret shame....
Beware the carbon envy!
unless you're a very serious racer, I don't think you'd see the difference !!
I sail nearly every day and can't see or feel it 
Your bank account will !!!
I didn't think it made a difference....Until I went 100% carbon. I only use waves sails so I can only comment on my perspective. I now find that the sail is more responsive and comfortable across the wind range, has more power and yet a softer feeling in the gust and a much smoother acceleration. I'm a gumby so if I can tell the difference I'm sure you will.
My 2 cents...actually it was 100000 cents but worth it. 
I would think your best off looking for the advice and guidance from those in the know at the Inverloch Windsurfing club.
Extremely knowledgable bunch who will never steer you in the wrong direction.
^^ that's strange cause I would expect a 100% to give a "stiffer" feeling and more brutal and "instant" response/acceleration, mind you I don't have wave sails so can't really compare, but Salty is talking about a cammed sail
The comfort factor is mostly due to the light weight of the 100%, so if you can afford it, enjoy.
On the downside just be cautious when handling, 100% do not like bumps or hits/shocks, they then tend to break more than a 75%
most important : go for the recommended mast 
You probably have 75 per cent chance of breaking the lower carbon mast as opposed to 100 "" chance of breaking the higher carbon mast.
The question is about RDM's is it not, I've read that 100% SDMs give you a stiffer and more powerful feeling in race sails but I've got nothing to back that up, And that running RDMs in your cammed sails will make them softer and more forgiving in gusts but less powerful...Once again nothing to back it up. I ran 65% carbon or less masts for the first 3 years of my windsurfing and was quite happy, This year I changed to 100% carbon and it's changed my sailing for the better.
No expert here, Just what I noticed.
Select to expand quotejh2703 said..
The question is about RDM's is it not, I've read that 100% SDMs give you a stiffer and more powerful feeling in race sails but I've got nothing to back that up, And that running RDMs in your cammed sails will make them softer and more forgiving in gusts but less powerful...Once again nothing to back it up. I ran 65% carbon or less masts for the first 3 years of my windsurfing and was quite happy, This year I changed to 100% carbon and it's changed my sailing for the better.
No expert here, Just what I noticed.
Actually the question is clear... is it 75% RDM vs 100% RDM, or 75% RDM vs 100% SDM? In either case, the "correct" answer lies in the details...
From a carbon-content point of view, if the sail requires high-skin-tension, then higher carbon content is better as higher-content usually means "faster/reduced response time" to gusts. That statement is less clear for lower-skin-tension sails, as the sail material is already absorbing some of the gusts. But as been said here (and in every brochure since about 1980), lower weight rig ~~ better.
If it is an RDM vs SDM thing -> the reality of RDM vs SDM masts is that:
a) the overall outer shape differs, so they have a different bend characteristic,
b) generally** an RDM will be on the low-side of the IMCS, where as an SDM will be on the high-side, so different bend curve.
** some RDM's have specifically been built to rig very similar to an SDM, often at the expense of extra weight.
So the sail must be specifically designed to be rigged on an RDM, ie: generally speaking, more seam-shaping below the boom.
In the case of cammed sails, it will depend on the year of production -> old cammed sails didn't make use of the cams due to lack of seem shaping, whereas a modern cammed sail can probably be used by either (provided the cams fit on the different mast diameter), but may sacrifice/enhance some aspect. ie: The old NP RS5 was notorious for destroying masts due to the rather distinct change in seem shaping right near the mast-joint - it would be interesting to see how that rigged on an RDM.
For example, at 74kg I tend to prefer RDM's as they tend to make the sail feel a little more spongy to absorbing gusts. But it really depends on your own preference.
Old Salty - if you are looking at SDM definitely go for the lower carbon content. The 100% masts break with monotonous regularity. Very upsetting to have $1000 go BANG! when downhauling even though it has always been treated nice.
If RDM I agree with jh2703 - they are more durable and 100% RDMs don't break all the time. Thus it may well be worth the 'feeling' benefits - depending upon your wallet.
Select to expand quotemathew said..
Actually the question is clear... is it 75% RDM vs 100% RDM, or 75% RDM vs 100% SDM? In either case, the "correct" answer lies in the details...
From a carbon-content point of view, if the sail requires high-skin-tension, then higher carbon content is better as higher-content usually means "faster/reduced response time" to gusts. That statement is less clear for lower-skin-tension sails, as the sail material is already absorbing some of the gusts. But as been said here (and in every brochure since about 1980), lower weight rig ~~ better.
What would the response times be if the 100% carbon mast had exactly the same weight of a 75% mast?
So it had the same stiffness, and equal weight?
Select to expand quoteMark _australia said..
^^^ how could it?
Easy, thicker wall section and different lay up/ fiber orientation.
Good point Al. I read it the other way around, making a 75% just as light (duh)
more carbon, and thicker - but same weight? my head hurts Barn what's ya point
Select to expand quotegavnwend said...
You probably have 75 per cent chance of breaking the lower carbon mast as opposed to 100 "" chance of breaking the higher carbon mast.
Best 'basic' answer. For performance - go high carbon. Between 50% - 75% will generally give you a good combination of value and performance. Anything high performance is generally priced accordingly - therefore for those that can afford breakage in order to gain those extra kts. ;-)
Select to expand quoteMark _australia said..
Good point Al. I read it the other way around, making a 75% just as light (duh)
more carbon, and thicker - but same weight? my head hurts Barn what's ya point
The response time doesn't come from the carbon content. Just the stiffness and the weight.
Stiffness stores the energy, weight determines how fast the energy is released.
So theoretically you could have one 60% carbon mast feel the same as a 75% if they both weighed the same and had the same stiffness. One could have thicker walls.
Dunno, I don't really have a point!
