TonyMS
Well-Known Member
- Joined
- 16 May 2001
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- Winter St Ives, Cambs; summer Ionian
Does anyone sell this? Might be ideal for rudders.
Tony MS
Tony MS
Unidirectional plywood
- Thread starter TonyMS
- Start date
tedsmith
Well-Known Member
Why would it be good for rudders? The single direction?
boatbuilder
Well-Known Member
Its called a plank
tillergirl
Well-Known Member
Plywood gets its strength and stability from the laminates being laid at right angles to each other!
VicS
Well-Known Member
[ QUOTE ]
Might be ideal for rudders.
[/ QUOTE ] I think I'd prefer to stick to solid timber but if I was using ply I would cut "on the diagonal". That overcomes the problem of half the plies having the grain in the wrong direction.
I'd be interested in expert opinion on the idea though.
Might be ideal for rudders.
[/ QUOTE ] I think I'd prefer to stick to solid timber but if I was using ply I would cut "on the diagonal". That overcomes the problem of half the plies having the grain in the wrong direction.
I'd be interested in expert opinion on the idea though.
Spuddy
Well-Known Member
Advantages would be same as for laminations, I suppose - easier to control uniformity with no hidden flaws.
milfordman
Well-Known Member
The rudder on my boat is made up from 3 pieces of 6" by 2" mahogany. I always thought that the reason was that timber 18" by 2" would be very expensive and difficult to source. By laminating several piece of timber together produced a more stable component less likely to distort is split.
Is this what you meant by unidirectional plywood?
Is this what you meant by unidirectional plywood?
ccscott49
Well-Known Member
If you mean bendy ply, robbins do it.
Solent sailer
Well-Known Member
i have used this stuff at home, very useful for a curve but i wouldent like to rely on is for strength, virtualy all the laminations run in one direction with just 1 or 2 very thin ones at right angles to hold it together
srp
Well-Known Member
I think what you are talking about is plywood with laminas running at 45degrees to each other instead of 90. This makes it considerably stiffer in one direction than the other, but retains the stability, flatness and accurate finished thickness ply has compared with solid timber. It is not 'bendy' plywood used for tight curves, quite the opposite in fact.
If you use it to make a rudder or centre board it would be oriented so that the grain direction runs 22 1/2 degrees from the vertical (ie half of 45).
Although I have seen it referred to in a number of books and magazines about boat building I have to confess I have never used it or even seen it for sale. As another poster mentions, Robbins is the place to go, though I had a quick look and couldn't find it on their web site.
If you use it to make a rudder or centre board it would be oriented so that the grain direction runs 22 1/2 degrees from the vertical (ie half of 45).
Although I have seen it referred to in a number of books and magazines about boat building I have to confess I have never used it or even seen it for sale. As another poster mentions, Robbins is the place to go, though I had a quick look and couldn't find it on their web site.
earlybird
Well-Known Member
Going back some 30+ years, I seem to recollect this material being sometimes specified for sailing dinghy centreboards, where the bending load is quite severe in the one direction. It had more veneers running in the "lengthways" direction. I don't think that, in practice, it had any real advantage over a good piece of solid timber. If there are still builders of wooden racing dinghies about, they might help.
