samang1
23rd March 2006, 11:39 AM
I am going to build a wooden sailboat. It is 20' long and weighs approx 2000 kgs. I am trying to save as much money as possible. Is it possible to use plain ply as long as I seal it properly?
jmk89
23rd March 2006, 12:37 PM
I am going to build a wooden sailboat. It is 20' long and weighs approx 2000 kgs. I am trying to save as much money as possible. Is it possible to use plain ply as long as I seal it properly?
I wouldn't - the issue is not so much the glue (same glue used on marine and exterior ply) but the voids and knots in the cores and thye quality of the surface veneers. Exterior ply is ok for Puddleducks - but you can see from the tread on building those boats:
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=28107
that the voids can be quite dramatic. If you are going to put in the effort of building and sealing properly - make a proper investment in good marine ply.
There is a good article on what makes ply Marine Ply in the current issue of Australian Amateur Boatbuilder which you should try to get a copy of.
bitingmidge
23rd March 2006, 12:40 PM
Yep.
But you won't necessarily be happy! You may save something less than 2% of the construction price of the total boat, and you have just cut costs on one area you won't be able to upgrade later.
Marine ply has the same glue, as exterior grade, but has inner plys of better quality, and SHOULD contain no voids in the core.
Check out this thread for a bit more, and don't forget to look at the pictures of the voids in the structural grade ply in our PDRacer project! :eek: :eek: :eek:
http://www.woodworkforums.com/showthread.php?t=28564
You'll also see the argument raised by Daddles against marine ply after he was sold a dud batch....
My advice: don't skimp on the hull materials, you are going to spend a lot of money, and if you get the core wrong, you can't fix it later.
You will easily save the same amount by making some of your fittings, or maybe leaving out some windows (which will eliminate a source of leaks as well). I'm assuming a 2000kg twenty footer isn't an open dinghy, that's no lightweight!
Hope that helps a bit,
cheers,
P (whose 16 footer weighs 120 kg! ;) )
:D :D :D
bitingmidge
23rd March 2006, 12:42 PM
Thanks jmk! I's a bit slow on the trigger today! :D :D
P
jmk89
23rd March 2006, 01:12 PM
Just wanted to show that I have been learning by watching what is going on.
You are right Monsieur Midge on the point that this is a non-upgradeable area. Save money with thigs that you can replace with better quality or more features if you get money later, not on fundamental structure. Booms, masts and other spars can be upgraded, but hulls can't