Hi all,
I'm either getting a 50% or 70% carbon SDM mast for a new 7.8 sail (the curve on my old mast just looks bad in the new sail). Does the mast carbon content affect speed and planing ability?
I've read that carbon content affects weight and "responsiveness" (which I interpret as speed of your rig to react to gusts or lulls?), but aside from the slight weight difference does the mast carbon content have much impact on speed?
In my spot on Lake Huron we rarely get over 10 knots of wind. The price difference is around $200 for 70% vs 50%.
Go with the highest carbon for easier uphauling, if anything else. The lower the carbon content the heavier the tip of the mast, and that is very noticeable. I tested a 100% carbon mast versus a 70% carbon mast, each was laying on the floor and picked them up "tip first" from the base end, could really feel the extra weight in the tip of the 70% mast.
once I had a 30% carbon mast for a short time and it felt like sailing with a telegraph pole, get the 70%, masts usually last a long time
Select to expand quotepowersloshin said..
once I had a 30% carbon mast for a short time and it felt like sailing with a telegraph pole, get the 70%, masts usually last a long time
I had a 40 % carbon mast . I went on a Guy Cribb course and he picked my gear ( 4.2m sail) to do a dryland gybe demonstration. After 5 mins he gave it away and found some gear that was lighter.. 
Extra carbon will feel better and be lighter especially as you're going to be using a larger heavier sail anyway.
You can definitely feel the difference between a 30% compared to a 100% especially the way the top of the sail whips back into shape . I'm not so sure if its the weight at the tip or the springiness of the carbon . Probably a bit of both . lot more lively feeling .
Not so much between a 50% and 70% especially in 10kts. What is the weight difference ? If it was 90% there would be more difference .
Select to expand quoteImax1 said..
What is the weight difference ? If it was 90% there would be more difference .
2.8kg vs 2.25kg
The 90% is 1.95kg but isn't sold in my province and likely much more expensive. My old mast is 75%.
You wouldn't feel half a kg uphauling a submerged 7.8m sail out of the water , especially if it's a cammed sail . Remembering that weight is along the whole length not at he tip . I'd even doubt you would feel much swinging the sail around . Mabee with a little wave sail . In 10 kts I doubt you would feel much in performance , unless your into pumping the sail . But if you can afford it I'd go the higher carbon for when you are planing where you may feel a difference . Or you could save the money for a bigger sail which you will definitely feel the difference .
Cannot justify paying 1500 for a 100% for a carbon mast.Yes they are good. They bring the best spring back rate in any sail.you certainly do notice the benefits from a 30% to 80% onwards.
Select to expand quotegavnwend said..
Cannot justify paying 1500 for a 100% for a carbon mast.Yes they are good. They bring the best spring back rate in any sail.you certainly do notice the benefits from a 30% to 80% onwards.
I got a used Powerx Zspeed 100% 460 carbon mast for $130 US, been going strong for 5+ years. Found on Craigslist, was a local shop selling off a whole lot of used gear, Thanks Britt at North Beach Windsurfing!
You will not go noticeably faster with a 100% carbon mast v's a 50-70% carbon mast, but it will be noticeably lighter and easier handling.
The higher the carbon content the lighter the mast, but with SDM masts this also means thinner walls and that makes 100% Carbon masts much more vulnerable to micro cracks and damage, ultimately significantly increasing the chances of it breaking. For SDM masts, 70-75% Carbon has proven to be the best compromise of light v's durability for a lot of sailors. If you go 100%, treat you mast extra careful regarding knocks and bumps and use a boom head that does not distort the mast when clamped and has a large bearing surface.
For RDM masts, go 100% every time if you can afford it. The small diameter and the much thicker walls is why they are very durable.and the difference in weight and fell are significant in RDM. 
As a beginner and now intermediate my 100% carbon 490 (Epic made in Italy) and 460 (Powerx made in USA) SDM masts have taken a beating in shore breaks, and impacts from me hitting them, and are still working great 5-6 years later. But I have always been careful to not over tighten the boom head clamp, and for one boom the head clamp plastic insert was too hard and it slipped a lot on the 490 mast which had a slippery outer wrap on it. Instead of tightening the boom head clamp up, I contact cemented truck tire inner tube rubber on the three faces of the clamp, that kept it from slipping on the mast with moderate clamp pressure. I was warned by someone at a store, you can crack a 100% carbon mast with too much boom head clamp pressure, but have to go by feel to determine what is right and what is too much. So I always set clamp to the minimum pressure needed to not slip, and that was done by trial and error (slipping). Better to error on the slipping side versus the cracked side
Select to expand quotedavidskis said..
Hi all,
I'm either getting a 50% or 70% carbon SDM mast for a new 7.8 sail (the curve on my old mast just looks bad in the new sail). Does the mast carbon content affect speed and planing ability?
I've read that carbon content affects weight and "responsiveness" (which I interpret as speed of your rig to react to gusts or lulls?), but aside from the slight weight difference does the mast carbon content have much impact on speed?
In my spot on Lake Huron we rarely get over 10 knots of wind. The price difference is around $200 for 70% vs 50%.
As other have said: get the highest carbon content you can afford. It makes a big difference in weight and response of the sail. Check out a small comparison here: www.seabreeze.com.au/forums/Windsurfing/Review/Point-7-SDM-K80-K100-weight-distribution
I generally use 100% carbon, they are more expensive but still not that expensive from Point-7. They actually suggested to use 80% only for very small sails, 3.7-4.2-4.7, in rough conditions, although I ended up using an 80% bottom and 100% top for 3.7.
Select to expand quotedavidskis said..
Hi all,
I'm either getting a 50% or 70% carbon SDM mast for a new 7.8 sail (the curve on my old mast just looks bad in the new sail). Does the mast carbon content affect speed and planing ability?
I've read that carbon content affects weight and "responsiveness" (which I interpret as speed of your rig to react to gusts or lulls?), but aside from the slight weight difference does the mast carbon content have much impact on speed?
In my spot on Lake Huron we rarely get over 10 knots of wind. The price difference is around $200 for 70% vs 50%.
What is the new sail? Does it not recommend what mast to use? That's what you should be checking & getting. Without knowing the kit that you're looking at, the gurus here may not be able to give you the best advice.
