Dear people, Our site has been updated. We kindly invite you to have a look at: www.wangkaboats.eu Suggestions and criticism is welcome at: info@......
Dear Wangkas, Nice pictures and all, but where is a finished sailing boat? Also, what do you hope to acheive with around beam? Thanks again for your mast...
Dear Doug, Dear Wangkas, Nice pictures and all, but where is a finished sailing boat? We know it takes a long time, but sometimes we have other worries on our...
Hi, Just meant swinging around on the water, like anchored in the sea breeze comes in 20knots. I was wondering about general ideas about swinging around coming...
... breeze comes in 20knots. ... from experienced multihullers out there. Like when you anchor a bigger boat out further where the wind is. What about two...
Easy enough to check if the masts are strong enough. Load them up by trying to lift the ww hull with a 100kg weight sitting on it. I was looking at the...
Robert, I'd like to sense a failure ahead of the crack, split whatever, so as to salvage the mast and simply add more glass around the outside. But that would...
G'day, Not that easy as the pulling load has to be evenly distributed along the mast. Needs a lot of pulleys so that the single load can be dissipated to...
-I would have thought that with the safety factor needed for gusts and wave actions it wouldn't need quite that level of load spreading. The mast has to be...
G'day, You are right (and I am wrong) about 2 masts vs one. The stiffness and the strength are different, and it is the strength which needs to be enough to...
-I was giving a lecture the other day about diffusion rates of CO2 across stomata of tree leaves- big topic at the moment with CO2 increases effectively...
If it is composite, you will hear a lot of creaking and cracking before it breaks. I would work on one of them doing the lifting as in a capsize you will...
Rob, Is composite glass/kiri? Doug Rob Denney <proa@...> wrote: If it is composite, you will hear a lot of creaking and cracking before it breaks. I...
G'day, Yes, but the stiffer it is, the more cracking there will be. My understanding of this is that the noise is the resin cracking as the carbon is so much...
Hi Rob, I dont see why the resin should crack because the carbon is stiffer. If the resin cracks it is because it is stressed beyond its maximum strength. The...
Peter, The point about matching strains is a good one, but I believe the carbon's modulus is magnitudes higher than that of the epoxy matrix, so we won't...
After much research, I agree with both Peter and Rob. In summary: epoxy cracking likely occurs in first tension on the leading edge, while structural failure...
-Thanks Mike, I didn't realise that carbon had greater stetch before breaking than glass. My thought on the creaking and cracking concur with yours that it is ...
g;dAY, hI, i KIND OF STARTED THIS TOPIC on masts, and was just wanting to say that tapering the end in at the top means using mirrored shapes of the moulds...
-I am pretty sure that tapering the mast makes it less likely to break as it takes some of the shock out of the system and reduces weight aloft. IMHO I think...
G'day, Makes sense, I think. I am pretty sure that a carbon laminate cracks sooner than a wood epoxy one, but have absolutely no data to back this up. Must...
If the modulus of the resin and fiber were the same we wouldn't need to add the fiber in the first place. There is an order of magnatude difference for epoxy...
Hi Mike, Fair enough, I am in a similar position, as a machanical engineer, but with some background in composites which is unfortunately largely forgotten. ...
It would be nice to know the cause, as it may have implications for fatigue or simply to put my mind at rest when I hear the boat creaking and cracking in a...
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