Does a higher carbon content make a mast more brittle or susceptable to breakage? Been looking at masts, besides the benefit of weight what would be the benefit of a 100% carbon mast as compared to say a 60ish% mast.
NB. only recreation use with the odd rinse cycle.
Thanks

Main thing is reflex response or how fast it springs back after gusts or bumps. The rig is almost continually flexing as you sail along, particularly in chop. Not sure about lifespan though, it seems like they eventually fatigue and break earlier

*Wargle fargle bargle...*buuurp*...*puke*....

if your worried about cost NP is releasing X3 and X6 skinnys in a few months.
i believe a 400 X3 RDM was only $50 more than the current X3 SDM so about 400ish.

Thanks for the info Bertie & little Jon, cost & durability is a main factor. I have to try and convince the Mrs that I need one. I was trying to see if the higher carbon content is necessary for my mediocre abilities.

If you buy a RDM mast go for 100% carbon,even if your skills aren't quite up there you will benefit from the lighter rig and performance.

Been wondering this myself Mabbott

Pretty sure higher percentage of carbon means more brittle (in SDM at least), but in the skinnies i'm not sure, as have heard mention that higher carbon percentage is more durable in RDM.

Bought a 100% RDM Loft 460 a few months ago, response is awesome, but not sure if should get 100% again or 75% for a 400 that i'll get for the waves soon

Any ideas people?

dism, you're looking at a few different arguments in one paragraph. RDM's are stronger than SDM's because they have thicker walls. They can be thicker with no weight issues because they are a smaller circumference. Carbon is as brittle in any product whether or not it's a boom, extension, mast - it's how it's used (and reinforced) that affects it strength. Masts with more glass (eg 60%) should be more durable.

So, IMO the best masts are 100% Carbon RDMs as they are light, stronger than 100% Carbon SDMs and as Little John pointed out they have a much faster reflex rate. My Loft sails on Loft RDMs feel awesome, I rigged the same sail with a 30% SDM and it was no where near as nice.

As for using 100% carbon masts in the waves - i'm still a bit dubious and wonder if 60% might be a better option? Not sure what other people think.

actually you will find that RDM's are slightly heavier then a equivilent SDM of the same carbon % and length. I think you will also find that in general RDM's will be more flexy then a equivilent SDM (which will be stiffer), so depending on what you sail, and how the sail is designed, would give you the end characteristics. One big point is that I think now days at least for smaller sails, (wave sails) in particular, all the testing done by manufacturers would be done with RDM masts, and so the sails would most likely rig the best on a RDM

As far as strength and breakage, speaking from an engineering standpoint I don't think there is anything in the material properties which says a higher carbon % mast should snap easier. A big contributing factor would be manufacture, as the manufacturing techniques have a big impact on the end strength of a composite product. I think the main reason why some high % carbon masts had a reputation for being fragile would be because the material is stronger the manufacturers built them with smaller wall thickness to further reduce the weight, and the end result would be something that wouldn't tolerate abuse as much.

Unfortunately manufacturers won't tell you in on the specific construction of their masts, so I think best thing is to go with something that has a good reputation. I think powerex have a really good rep as far as RDM masts goes. And go to a local shop with your sail and rig it on different masts. Kinda tough thou as most shops don't carry a huge variety.

Some online magazine had a really good comparison articles where they compared lots of SDM and RDM masts on lots of sails. I think it was one of the UK mags? Anyone happen to have it bookmarked? I'm after a new mast as well, most likely a RDM and I remember it being a good article, can't find it anywhere thou.

Swoosh, it was in the Boards Magazine about a month or two ago - they tested masts for flex, weight etc and tried lots of masts (recommended ones and non-recommended) on all the wave sails.

It was very interesting - particualry when they suggested ignoring the recommended mast length and trying different masts instead (eg use a 430 with 25cms on extension rather than the recommended 460cm mast with 5cm sticking out the top).

I think it was the May 2008 Edition.

I think skinnys are the way to go... but im left with a problem..

If i were to be getting a quiver of Pryde Wave Sails, should i buy an X6 Skinny with 65% carbon (or whatever) or should i buy (with the same money) a powerex 85% Carbon skinny.

Aka, should i stay with the brand?

Hey, I run 100% Ezzy RDMs, and love them. Never had them before, they're so much more resposive. I didn't think I'd notice the difference, but I'm not going back to SDM in a hurry. The Ezzy ones have interchangable tops and bottoms so you cna use a 430 bottom with a 400 top to make the perfect length mast so as not to use too much extension, and I think they come with a 2 year guarentee. Only had them 6 months, so can;t comment on durability, but I've not heard of any problems with them. Go for it says I... you won't regret it!

> have to try and convince the Mrs that I need one

You could be extra-nice to her for a while, but doesn't always work and could be a waste of time

I've found that RDM are very reponsive as well,my Blade race sails really breath with ease and simply feel very different to SDM masts,another positive is that you can use the RDM masts in wave sails and there are a few brands now that use RDM masts in their race/freeride sails etc The Loft,Gaastra,Naish saves buying two sets of masts for waves and race.

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sflack said...

I think skinnys are the way to go... but im left with a problem..

If i were to be getting a quiver of Pryde Wave Sails, should i buy an X6 Skinny with 65% carbon (or whatever) or should i buy (with the same money) a powerex 85% Carbon skinny.

Aka, should i stay with the brand?

The Powerex will probably flatten out the NP sails a bit. Powerex used to claim their skinneys were 12% bend so I assume they are close to that. NPs are more like 15% ie soft top and I believe their skinnies are supposed to stick to this bend. The upper leach would be a bit less free also.

Haircut runs a powerex skinny with his Alpha and loves it. The Alpha is the most powerful of the NP wave sails. The px probably makes the Alpha more like a Combat or a Zone.

Best advice is try before you buy.

Are RDMs skinnier at the top than an SDM, or similar at the top with less taper? My mast is a bit tight in the top of the mast pocket of my most used sail which makes rigging a PITA.

the skinnies i've seen are all just as fat at the very top as a fatty

as far as performance with NP sails - davecta said he noticed an improvement when he swapped from a fatty NP mast to to a new skinny NP mast with his np wave sail - if that's any help. the powerex skinny i got certainly rigs & feels better with the 2008 alpha than it did with the 2006 combat, but not sure that really indicates alot. the combat's shape moved around alot in higher wind, but the alpha is equally good at both ends of the wind. i'm pretty sure both sails had equal bottom end, in fact they looked virtually identical when laying the 5.6 combat on top of the 5.8 alpha. not sure where the extra .2 comes from

i'm not going to generalise with other brands but if you rig NP sails with NP masts your on a winner.

Higher carbon always equals faster reflex/response but with a price tradeoff.


Sflack to solve your problems >>WSP has some runnout combatX rdms for only $650 atm. They were over 800 when i got mine and the are 100% carbon or close to as possible.

I have the two issues of Boards magazine in digital format where they tested a range of SD and RD masts (May 2007 430cm test & April 2008 400/460cm test). I use downloadable software called 'Zinio reader' to open the digital mags and from what I understand, I am able to give away at least three free copies of each mag to 'friends' (never tried it before though!). If anyone is interested, send me your email address via Seabreeze (click on my username at right).

I certainly will be much more aware of choosing masts to suit brands of sails from now on after reading the articles. I think that the Boards test team have been doing a fantastic job of clearing up a lot of misconceptions re mast IMCS ratings, the so called 'constant curve' mast as well as sail/mast compatibility. I now firmly believe that the only way to know whether a sail suits a particular brand, style (SD, RD or Hybrid) or carbon content of mast would be to rig it on that mast and pay attention to how the head/leach twists and how the battens rotate/derotate, assuming you have a good understanding of what the sail should be doing (would be great to be able to demo different masts in different sails, wouldn't it!).

Last year, I traded a NP 430 X3 mast for a NP 430 X6 mast and was surprised how much better all of my sails (both NP and other brands) rigged and handled, for the better of course (so much for the NP 'Matrix' system!). Also, the common misconception that 'NP sails work best with NP masts' may be untrue as according to Boards mag, there are other 'flex-top' masts on the market including Tushingham and (some) Powerex that appear to have bend curves similar to NP masts.

For more info about masts, check out great tech article at:
www.peterman.dk/windsurf-mast-article-gb01.htm

Also, IMCS mast database:
http://www.peterman.dk/masts-all-imcs01.ht

Re carbon mast breakage:
www.carbonsugar.com/construction/why-do-masts-keep-breaking/


Conclusion: buyer be-aware!

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have to try and convince the Mrs that I need one

You need one. Sails are being designed to work with them. They handle (in the hands) brilliantly. They're probably a little faster. They're more resilient in the waves. And if your wife ever windsurfs, she will greatly prefer the thinner mast (insert joke here) when tacking and waterstarting.

RDM vs SDM