Aluminum vs. Carbon Mast and Fusalage

[windmaker]

There can be large differences in quality between carbon and aluminum masts.
The aluminum mast from Alpine are lighter and stronger than some carbon masts from other brands.

Good aluminium is better than crap carbon. So many different qualities of carbon and ways to lay it up. Just like bike frames.

I recently fixed a friends damage carbon foil (i d rather not mention the name/big brand), only the visible outside visible skin was carbon so say 5% total.

[Foil]

My 2019 slingshot mast is 2.1kg without the base plate,
However the wall thickness is beefy to say the least.
Check out the photo below and compare with the weaker thin wall ones.

[alowishus]

It's simple with masts. Carbon can be a bit lighter and a lot stiffer than aluminum, but it is more expensive. You decide whether you want to spend more money for a nicer ride.

I've heard conflicting information regarding weight vs stiffness for carbon... I'd love to see actual data

I haven’t got the experience to really tell a floppy mast from a stiff one, but everyone says the stiffer the better.

Given the number of choices on the market now it would be great to have metrics to make comparisons between products and to really know what you are getting. There are some of course, and each manufacturer has their own marketing strategy. Similar to the idea of manufacturers labelling their wings with basic comparable info such as area and wing span. Other KF thread. Maybe not so easy with wings.

Mast info should be easy, no? Dimensions, weight, “modulus of elasticity” and Stiffness (EI) both axes.

Moses say their 101+ masts are “high modulus”. But they use “top materials” for all their products. Axis say their latest mast is stiffer than the previous model. Not saying any of this isn’t true. Latest Slingshot aluminium masts only seem to have changed in appearance and small change in length (full length mast from 35.4” to 35.5”). They don’t tend to talk about the weight of their foil too much.

I’m sure someone has done some kind of home lab stiffness testing of their masts, which would be the only way with composite materials. If anyone has actual data it would be pretty interesting.

[Kamikuza]

I haven’t got the experience to really tell a floppy mast from a stiff one, but everyone says the stiffer the better.

Given the number of choices on the market now it would be great to have metrics to make comparisons between products and to really know what you are getting. There are some of course, and each manufacturer has their own marketing strategy. Similar to the idea of manufacturers labelling their wings with basic comparable info such as area and wing span. Other KF thread. Maybe not so easy with wings.

Mast info should be easy, no? Dimensions, weight, “modulus of elasticity” and Stiffness (EI) both axes.

Moses say their 101+ masts are “high modulus”. But they use “top materials” for all their products. Axis say their latest mast is stiffer than the previous model. Not saying any of this isn’t true. Latest Slingshot aluminium masts only seem to have changed in appearance and small change in length (full length mast from 35.4” to 35.5”). They don’t tend to talk about the weight of their foil too much.

I’m sure someone has done some kind of home lab stiffness testing of their masts, which would be the only way with composite materials. If anyone has actual data it would be pretty interesting.

I've heard that windsurfers don't want completely rigid foils because of how they ride ... but I think kiters would.

Yes to the Axis masts being stiffer -- 200% -- because it's a new (as of last year) design. I think that's a theoretical measure based on materials analysis software, though there was a plan to do physical tests at a university...

I think we need side-to-side deflection but IMO more importantly, "twisting" stiffness. Is that what you mean by "both axis"?

My Axis SUP mast (thicker than kite mast ... 19mm vs 15?), plate and bolts (incl. plate bolts) weighs 2.1kg. Quick check online and the J-shapes mast (only brand that clearly listed weight) is 1.4kg without hardware. So lets say 1/3 lighter for 3 times the price?

[Kamikuza]

I haven’t got the experience to really tell a floppy mast from a stiff one[...]

IIRC someone said the original SS mast was sloppy, and I do remember many instances of rotating the board for a turn but having the foil keep tracking straight. Or at least, that's what it felt like at the time... Some masts have felt a bit "vague" in side-to-side input response while riding too.

[alowishus]

I think we need side-to-side deflection but IMO more importantly, "twisting" stiffness. Is that what you mean by "both axis"?

I’m guessing someone will chime in here with a better grasp of solid mechanics, but I guess bending stiffness (K) as well as torsional stiffness (CJ/L) would be the go.