% carbon mast in 370 mast size

loonie2 · Joined: 18 Jun 2004 Posts: 145

I'm wondering how much a peformance difference there is between say a no Limitz skinny 91% mast vs powerex SDM 60% wave mast? (for a sailworks sail).

U2U2U2 · Posted: Sun Feb 19, 2012 11:34 am Post subject:

from 430 down I prefer RDMs

460 I have both, and its a toss up.

for your question the weight is going to be close to the same.

If you have RDM extensions and the price is near the same I would go with the RDM.

Is it going to be used a lot or occasional.........

both masts should suit the Sailworks, some perfer the SDM overpowered, others the skinny

kmf · Joined: 02 Apr 2001 Posts: 503

I asked Dale Cook this question last summer, Fibrespar Reflex Wave 70% carbon SDM vs Sailworks Backbone RDM and he recommended the RDM. I liked the results, although I bought a 400 and a 430. I kept my 370 Fibrespar STD as I only use it for one sail, a 3.4 meter Revolution and I refuse to buy a $400 mast for one sail that I use perhaps 4 times per year. I will look for one at the swaps.
As to specific mast to sail recommendations, call up the sail manufacturer for recommendations.
KMF

loonie2 · Joined: 18 Jun 2004 Posts: 145

Thanks for the input. The mast would not be used much. However, those big days are memorable so I'd like to be better set up. I currently use a 400 (north 100%) & notice a significant reduction in performance/ range compared to sails designed for the 400. I only have STD extensions but may switch to skinnies - but probably not in the near future.

I guess to clarify my question, I'm wondering of 400 vs 370 mast performance for a sail designed for 370 (I expect this is obvious). Further, how significant is the carbon content on the small mast of the same size (370).

kmf · Joined: 02 Apr 2001 Posts: 503

I think that there are lots of variables in the mast question.
The recommended mast is the best choice and that should be one's first pick.
Unless one is very heavy.....or very light.....then almost all sail manufactures will call for the next stiffer.....softer....mast.
More carbon results in a more responsive mast-sail relationship. RDM's have 90-100 carbon. They will be more responsive than a 40-75% SDM. And tougher.
SDM's have passed the test of time. They work, they are cheap......unless sailing in the waves full time they are very cost effective.
Follow your pocketbook.

KMF

U2U2U2 · Posted: Sun Feb 19, 2012 1:38 pm Post subject:

I have way too many masts, but then I have way too many sails.

In the smaller sizes 340 & 370 for my Hot Sails I had an option of the higher carbon or less, something like 65% VS 95%,

since I'm light and I don't use these all that much I went for the 65% and quite a bit more attractive price.

In these smaller masts the weight difference is like having 4 or 3 footstraps, who cares

KMF offers some sound advise, but a good 100% SDM mast will often be lighter than a thick walled skinny, and YES the skinny is stronger in the waves, and there are alot of variables.

Sailworks are great, you can call and get their advise.

Here is what David Ezzy said about SDM/RDM, you are better to have the correct bend curve than worry about which version to use.

swchandler · Joined: 08 Nov 1993 Posts: 10588

I talked with Jim at Sailworks some time ago and asked him about their experience with No Limitz RDMs. He indicated that the No Limitz bend curve is slightly off for their sails. After breaking a 100% carbon Hansen 400cm, I bought a No Limitz gray RDM as a replacement. While the No Limitz works in my sails (Windwings), it's clear that the bend curve is somewhat different (a bit softer up top, yielding a more floppy leech).

Regarding your two choices, I would go for the Powerex, despite its lower carbon content, given that it will offer a better bend curve match for your Sailworks sail. Although I'm a big fan of high content carbon masts, I have to say that in smaller sails, lower carbon content isn't really a liability. Now, as masts and sails get bigger, it's a whole different matter.

loonie2 · Joined: 18 Jun 2004 Posts: 145

What U2U2U2 said is exactly my thinking - I'm not concerned about SDM vs skinny, rather, I'm interested in getting the proper performance out of a sail (I haven't sailed in surf). I probably shouldn't have said skinny at the beginning since this is a common debate.

What swchandler said suggests the answer to my question. That is, "in smaller sails, lower carbon content isn't really a liability..."

From what I understand from this is that there is a significant diminishing returns to higher carbon when down to the 370 mast size.

Is what I don't have the ACTUAL EXPERIENCE with a 370 mast size (never used one). Again - appreciate the feedback.

U2U2U2 · Posted: Sun Feb 19, 2012 4:57 pm Post subject:

isobars · Joined: 12 Dec 1999 Posts: 20935

Questions for the OP:
What mast does your sailmaker say is optimal for your specific sail?
How close does your sailmaker say an RDM's performance is to optimal?
Will you sail like Dale?
How long is your swim when an SDM breaks?
Maybe even more important, how important is spending a great high-wind session self-rescuing yer butt and your torn sail?

I dumped all my SDMs in favor of all RDMs after my last 1200 meter swim and the subsequent loss of a new 7.5 Retro after a new primo SDM snapped at the boom. By that time the issue for me was plain and simple: screw SDMs (my biggest sail is now a 6.2.) I'll be amazed if I ever break another mast in this lifetime.

Much lesser factors were that my sails are designed around RDMs and that while replacing my SDMs I found that RDM's can be had for peanuts around here. Is my 1-kg (2.2 pound) RDM mast, which is used only with my 3.2 and should also never break, worth the cost? IMO and so far, yes ... but get back to me after another decade of using it only in full nuke mode.

Did I mention that windsurfing is much more fun than self-rescuing?

Mike \m/