Does it matter which direction plywood lays on support beams? Does the 8' side have to go across boat or can it be run length of boat. It will take the same either way but I think that plywood is stronger when laid across beams length wise. At least thats what I was always told when I was in the construction trade. You always see ply run across rafters not up rafters. Also, is there any reason why steering center is placed at rear of boat? I would like to set mine in the front part of the boat. I know it means longer cables, but is there any other reason not to move to front of boat.
Since plywood is made of plys, with the grain facing in different directions, it seems to me that there would be very little strength difference. If I remember from your previous posts, you have a 17' boat, why not use two sheets going one direction, and two sheets the other? But I don't think there would be a strength difference. The main difference would be the seams. One reason for laying plywood across the boat may be so that there is not a seam going right down the center. The major flex in a pontoon is going to be side to side, since the pontoons themselves are pretty good sturctural members.Steering console, I'd want mine in the middle to the front of the boat too, and if I was rebuilding like you are I'd put it where I wanted it. No reason not to that I can see.Did you find where the water is getting into the pontoons?
It depends very much on the ply. The 6mm marine ply I used recently is 5 ply, but the plys are not equal thickness, the face and cores are quite thin compared to the other two. In fact the two thick ones add up to considerably more than the three thin ones, making it stiffer across the sheet than lengthwise, which is the opposite to what you'd expect by just looking at the grain in the faces.
I have always run the ply perpindicular to whatever I am attaching it to...just like the tradesmen teach you. I wouldn't want a long seam running parallel to the pontoons, unless you had some cross bracing under it. Just my 2 cents.
heyhauler, I have not taken to welder yet. Had to go to Dalton GA. for a week on busuness and that put me behind. I will be taking on Tuesday. I think that the leaks are under keel gaurd at front. When I get home today I am going to finish cleaning and may fill with water to see if I can find leaks without pressurizing logs.tim Mc I have 2" angle in center of frame so all seams and edges are supported. I do not like to have any unsupported edges or seams to bow up or down. Thanks for input all.Michael
I would run it accross the boat, not length wise. This way you won't have a joint over and unsupported area. Lay it out so that all of your joints fall on a cross member. If you run them length wise, you will have a joint running down the center of the boat causing it to be weaker in the middle where most of the stress is.
Run the long direction from one side to the other side. That way you have no joints running the length of the boat. The other joints should fall on a crossmember. The difference in home construction is that you use tongue and groove plywood which locks the unsupported joints together between the joists, but the non-T&G joints at the end of the plywood fall on a joist or other. Even on roofs with non-T&G plywood use roofing clips between the rafters if the ply is thin or the span is greater (24" O.C.).
pontoon decking
Also, is there any reason why steering center is placed at rear of boat? I would like to set mine in the front part of the boat. I know it means longer cables, but is there any other reason not to move to front of boat.
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