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-   -   Sail Size vs Mast Size/Weight (http://www.star-board-windsurfing.com/forum/showthread.php?t=5517)

robwootton 23rd March 2009 07:30 PM

Sail Size vs Mast Size/Weight
 
Hi All,

I have a quick query for you. For the benefit of the question, can we assume that the sails and masts are Tushingham and that a 490 mast greater than 45% carbon is not available:

Will an 8.6m freeride sail with a 490, 45% mast plane earlier/better than a 7m freeride sail with a 460, 75% mast?

It seems to me that the larger sail will obviously generate more force, but will its longer and heavier 490 mast (only 45% carbon) outweigh this benefit compared with using a slightly small sail which can take a smaller and lighter 460 mast (75% carbon). :confused:

Thanks,
Rob

Roger 24th March 2009 10:17 AM

Hi Rob,
Interesting question....
I've never used a 490 cm mast that was less than 75% carbon so it's difficult for me to imagine how much a 490 45% mast must weigh.
Here's the specs from the Tush website for the 45% Freewave mast:
Length : 490cm
IMCS: 29
Carbon Content :45%
Construction: wet lay-up
Weight; 3.00 KG. (6.6 lbs.).
The Tush Freeride 490 cm mast (75% carbon) weighs 2.35 Kg (5.1 lbs).
The Tush Pro Series 490 Cm Mast (100% carbon) weighs 1.9 Kg (4.2 lbs).
So, the 45% mast weighs 57% more than the 100% mast.
May not seem like much, only 1.1 Kg (2.4 lbs) but when you get the additional weight
out near the end of a 490 cm (16.08 ft.) mast, the additional weight really adds up.
If you are a big strong fellow, it might not matter too much to you, but if you are small to midsize and not super muscular, it will matter a great deal.
As to which sail will plane earlier, the 8.6 m2 will definitely plane earlier.
Is the 45% 490 mast recommended for this sail?
The IMCS looks about right, so the 8.5 should rig on the heavy mast pretty well and give you fairly good peformance.
So, yes, the 8.5 will definitely plane earlier, if you can deal with the tremendous additional weight.
If you can't deal with pumping the longer, heavier mast, to get going really early, you might have to just not sail on 8.5 m2 days, or slog on your 7.0 m2 freeride rig.
To tell you the truth, I was not aware that anyone even made 490 masts in 45%.
Hope this helps,

robwootton 24th March 2009 03:58 PM

Hi Roger,
Thanks for answering.
Tushingham still do a 490 45% mast.
I was using it with an older 8.6m Tush freeride sail for around 4 hours at the weekend...and you'r right its heavy!
At this size they do get you up and going in light wind, and are ok as long as you don't drop them in the drink, then they start to get very heavy once you've pulled them up a few times. (not water starting yet).
I was just wondering what was the point where the weight of a rig could overcome its size benefits.
I'm shortly going to get a 460 75% freewave for use with a 7m Tush freeride. I'm only 70kg so maybe this will be the better option for me until I have the water starts cracked.:)

Roger 24th March 2009 05:32 PM

Hi Rob,
If you were talking sail sizes a little closer together, there might be some point where a high end 100% mast could give you a bit of advantage, but the weight of the larger rig/heavier mast will always be something you must deal with and it really hurts the over all "feel" and responsiveness of the rig.
Also, if you were talking steady winds over 14 knots, then there may be some crossover points, but not at the min. planing threshold.
The larger sail size will probably always be the key to getting going early.


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