RDM VS. SDM

[Julian]

Hi there,

Next year I'm planning on buying the Code: Red in the sizes 4.6 / 5.6 / 6.7 / 7.7. For the 6.7 and 7.7 I'll have a Red Line 460 of course, but the thing that's left me worrying (can't sleep, just bang my head every day and night ) is the mast-thing for the smaller sizes. The 5.6 want's a 400 cm. mast, and the 4.6 a 370 cm. mast.

My question: Does anyone found out there are significant differences in putting a RDM mast in a fullrace sail. Please also consider the budget: If the difference is small I'd prefer RDM because of the fact that I can use those masts in my wave sails as well!

I heard an RDM makes the sail-feeling ''softer'' but I'm not quite sure what that's supposed to mean, but everyone says it should have advantages for a lightweight sailor like me (70 kg.) Anyone able to tell me more?

Thanks in advance,

Julian Gijsen

[Ian Fox]

Hi Julian,

the new Code:Reds will be setup to accept RDM option in the smaller (speed) sizes inc 4.6m/5.6m (these sizes are tuned to SDM Blue Line, masts not 100%RedLine anyway) . You will be able to use your RDMs doubling into wave use + also have the bonus of more bulletproof masts ~ in case of serious speed wipeouts . RDM has a theoretical lower drag and usually tests better with acceleration but the rig at top end is potentially not quite as super stable as with SDM. With a softer sail setting the rider is less likely to be lifted with a big gust (sail/mast deforming more to absorb the gust impact - but at the same time becomeing abit less efficent etc). For the larger sizes, the RedLine SDM is a very important part of the extra performance (including the very precisely matched mast/luff curves).

Sleep easy at night. No worries.

Cheers ~ Ian

[Julian]

Ian Fox wrote:
Hi Julian,

the new Code:Reds will be setup to accept RDM option in the smaller (speed) sizes inc 4.6m/5.6m (these sizes are tuned to SDM Blue Line, masts not 100%RedLine anyway) . You will be able to use your RDMs doubling into wave use + also have the bonus of more bulletproof masts ~ in case of serious speed wipeouts .

OK, sounds good, but what about the spacers? I heard that if you put a fullrace sail on a RDM mast, you'll need to put in a lot of spacers, not quite the thing that I had in mind Any reason to buy the 400 RDM in Redline, will it make a better combination with the CR 5.6?

RDM has a theoretical lower drag and usually tests better with acceleration but the rig at top end is potentially not quite as super stable as with SDM.

In what way is this notable for a ''regular'' sailor like me? Sail gets nervous when sailing with 7.7 in 20 knots?

With a softer sail setting the rider is less likely to be lifted with a big gust (sail/mast deforming more to absorb the gust impact - but at the same time becomeing abit less efficent etc). For the larger sizes, the RedLine SDM is a very important part of the extra performance (including the very precisely matched mast/luff curves).

So what you're saying is that for lightweight sailors (like me ) an RDM in a smallsized race sail is a smart thing to do, because (just trying to get this right ):

- Sail planes a little later, but is controllable for a longer time
- Can control gusts better
- The luff curve doesn't really cares whether you put in an RDM or an SMD?

Sleep easy at night. No worries.

I am, I am

Cheers ~ Ian

Thanks Ian, great help! If you could answer these last questions for me as well, I'll sleep like a baby

[-Lampi-]

The best thing to do is to look at what kind of mast the sail is designed for. For exsample I'm using RDM masts on all my hot sails maui sails, but on the NP expression i use a SDM, no matter the sail size.

The most important thing about the mast is - for me - that it has a lot of carbon in it (at least 75%). Although a C100% RDM is less likely to snap than a C100% SDM mast because it has thicker ''walls''.

[Julian]

-Lampi- wrote:
The best thing to do is to look at what kind of mast the sail is designed for.

I understand you're telling my that, and it's also my first intuition. But when I get to choose from:

1) Buying two (expensive!) masts and hearing that they don't really have a huge difference
2) Buying one masts that will work fine with both fullrace as well as wavesail, not perfect, but not notable for a regular sailor.

Then I must admit I will opt for the second option. However if there is a significant difference in the performance, I won't ''hurt'' my sails and put a wrong stick in 'em B)

For exsample I'm using RDM masts on all my hot sails maui sails, but on the NP expression i use a SDM, no matter the sail size.

Are those camber induced sails you're talking about?

The most important thing about the mast is - for me - that it has a lot of carbon in it (at least 75%). Although a C100% RDM is less likely to snap than a C100% SDM mast because it has thicker ''walls''.

I agree with you on that point, and that's why I'm wondering if there are any differences. If not, I will buy a Red Line RDM 400 and Blue Line 370 because of the fact that these masts are both lighter and more durable.

[-Lampi-]

Well...

[-Lampi-]

This applies to HOT SAILS MAUI sails only:

RDM masts are used on all Hot sails, including the speed and slalom sails, because they're made to work the best with the RDM's. Offcourse you can also get really good preformance out of them with SDM masts. My first sail was a 4.2 SO and i used a SDM mast. Then i bought a 5.0 SO (same year) and i put a RDM in it and the difference is BIG. The 5.0 is really easy to control, works really well when overpowered, it works really well in gusty wind. the RDM gives it more drag because you create a bigger ''baloon'' in the sail. The 4.2 is very direct, feels heavy although it is much lighter than the 5.0 and it doesnt handle as well as the 5.0 even though it's smaller. BUT despite what I've written about it, it still works very well and it's good when the wind picks up.

This applies to ALL sails, no matter what brand:

The difference between a mast with C50% and C100% is amazing. I didn't belive it when i first heard it but then i tried a c100 mast on my sail (i used a c50 before). Since then I use masts with at least 75% of carbon (im still not using 100% carbon SDM's because im afraid of breaking them). I've also heard people saying that 75%:100% is like 75%:0% carbon.

I've found an interesting article yesterday about the masts. its on

http://www.guycribb.com/page0076v01.htm
(the article i'm talking about is called ''mast debating'&#39

Hope this helps...

[Julian]

Thanks for the article Lampi! Very interesting

@ Ian Fox: Would an 370 and 400 BlueLine SDM give the optimal performance to the 4.6 and 5.6 Severne Code: Red? Because if so, that's gonna be my choise. Heard stories about screw*ng around with spacers and taking off pieces of the camber inducers (scary!) and therefore I think I'll just buy masts for my wave sails separately B)

P.S. Heard the news about a possible iSonic 73, great !