The deepest you could saturate any ply is to the first glue line and around the edges of the sheet. I've cut up a lot of epoxy saturated pieces of wood to see how deep the resin goes. In reality, highly thinned epoxy will penetrate maybe 1/16" deep if you are lucky and the wood is desert dry. 1/32" is more realistic. It's very easy to test your own materials and see this.<br /><br />You have to be careful when buying wood for boats. I bought 25 sheets of the expensive WEST sheathing ply (directly from WEST @ approx $50 ea.)a few years ago to "WEST" a 30' sailboat hull. If memory is right it was 5mm thick imported ply and sheet size was 5'x5'. I had several sheets left over and hung them in the rafters of my TOTALLY enclosed and weatherproof outbuilding. A few years later the ply delaminated...what a mind blower this was to see. It was supposed to be high quality marine ply with waterproof glue...but it wasn't. That boat was sold and gone shortly after the covering so I don't know how it held up for the long term. I used AB exterior to sheath two other sailboats and know they were still perfect 10-15 yrs later.<br /><br />If you want core material that is superior to wood look around at the structural PVC types like Klegecell. These are tough as nails and if they gets wet nothing happens except the boat weighs more. Only problem is few folks can afford to build a whole boat with it. Get some samples, you WILL be impressed.
Johnshan1,<br /><br />That is a VERY difficult question. While your boat is beautiful and no doubt rugged, it is unique. Personally, I would purchase something like that in the $8-10K range. Maybe more, depending on the engine. Yet, I know what it is and is not. That is NOT a boat that the average Joe can appreciate.<br /><br />If anyone were to buy it, it would most likely be a discriminating boater that loves wood (has probably built something like it) or a commercial use individual-IMHO.
Back when I bought the imported ply from WEST I think they thought marine meant "sealed in epoxy will make it water proof". I have never had or seen marine or exterior ply delaminate while sitting in storage. Careful storage will keep most ply from warping though. I talked to a boat builder who built large (80') plywood boats and ordered sheets by the hundreds. He made a stacking grid to air dry imported marine pt ply without warping. I don't know how big a problem checking is but I think saturating with epoxy keeps it from happening. None of my epoxy coated ply boat stuff has ever checked and that has to be 100 sheets or more. I grew up with plywood boats and most were done with exterior...some just painted and others glassed with 10oz cloth and polyester. They had very few problems if you kept them off the ground and dry. <br /><br />Here's one of my "WEST" jobs. I'm preping at this point. If memory is right it took approx 25 sheets (4x8x1/4" AB ext) to do the bottom and 60 gals of epoxy. This boat was done in 1980. The guy I sold it to has sailed from Florida to Alaska without problems with the sheathing. <br /><br />
Most designers of mid-size or larger boats will indicate where foam can be used and will help one to determine the minimum amount. Typically foam in poured under the sole and any unused compartments. I prefer 2-part closed cell foam that you mix and pour, but others use insulating foam panels, empty soda bottles or even those toy pool "noodles". <br /><br />The big decision is whether one wants simply positive floatation or level floatation. <br /><br />Positive floatation is the most common approach. With this approach, one will have enough foam in the boat to keep it floating in the event of a disaster. The hull will probably "turtle" on you (flip when water enters the cockpit and the center of gravity is changed - can happen very quickly), but it will float. <br /><br />Level floatation requires that you have enough foam located up near the sheer line to prevent the float from flipping if the cockpit is swamped. This may or may not be feasible depending on your boats design. Typically, you need a design with a nice size gunwale where you can hide foam underneath it.
