Opinion about plywood-epoxy contruction

amunk · #1 (**permalink**) 02-13-2005

I am considering a custom 35'' sailboat constructed from plywood-epoxy. I would appreciate some insight about this type of construction. I plan to live aboard and sail from the great lakes south to the Florida keys and beyond. The boat has a shallow draft and the living space is adequate for my needs. I really want to know more about the construction and what to look for.
Thank you

brazilnut · #2 (**permalink**) 02-15-2005

Amunk, have a look at the site of Brazilian yacht designer Roberto Barros (www.yachtdesign.com.br). He designs terrific yachts for home building and offers some good info on this type of building. You''ll find a link on his site to the Multichine 28 club, where a number of people have posted sites showing the construction process and final result. You might try to contact them to see how happy they are with their boats. I''m considering a Multichine 28 for myself and have no problem with its ply-glass construction.
Good luck,
Mark

Jeff_H · #3 (**permalink**) 02-15-2005

I think that you need to provide more detail because there are a number of contruction approaches that could loosely be called "plywood-epoxy" and they vary quite widely in their quality, and durability. Epoxy saturated cold molded plywood, in which individual veneers are laid up to create a hull that is in effect a single sheet of plywood can produce one of the strongest (for its weight), low maintenance, and most durable boat building techniques that there is. At the other extreme is a boat built from sheet plywood that is sealed with unreinforced epoxy resin, which is a pretty inexpensive way to build a boat but which is not all that strong or durable. There is an extremely wide range of variations in between.

Jeff

Jeff_H · #4 (**permalink**) 02-15-2005

brazilnut · #5 (**permalink**) 03-03-2005

Jeff_H, I''m wondering if you could offer a little more information about the different ply-glass techniques. As you mention, there are a number of them. The yacht that I''m looking at is a hard chine hull that has been made with a thin 6mm marine plywood core covered with epoxy resin and cloth. I understand the plywood core is like a skin that the layup covers but isn''t really there for its strength. It''s practically a pure fiberglass hull. It does eliminate the need for hull molds and allows for easy one-off construction. What do you think the drawbacks are to this type of construction? I wonder about the durability and issues like delamination, but from what I''ve read so far many of these boats have been around for years and years. Sailnet''s Michelle Potter built a boat using the same technique. I would really appreciate hearing a little more on this from someone who has built a boat with this technique. Thanks.

brazilnut · #6 (**permalink**) 03-03-2005

Jeff_H, I''m wondering if you could offer a little more information about the different ply-glass techniques. As you mention, there are a number of them. The yacht that I''m looking at is a hard chine hull that has been made with a thin 6mm marine plywood core covered with epoxy resin and cloth. I understand the plywood core is like a skin that the layup covers but isn''t really there for its strength. It''s practically a pure fiberglass hull. It does eliminate the need for hull molds and allows for easy one-off construction. What do you think the drawbacks are to this type of construction? I wonder about the durability and issues like delamination, but from what I''ve read so far many of these boats have been around for years and years. Sailnet''s Michelle Potter built a boat using the same technique. I would really appreciate hearing a little more on this from someone who has built a boat with this technique. Thanks.

paulk · #7 (**permalink**) 03-04-2005

I''d get a copy of Reuel B. Parker''s book : The New Cold-Molded Boatbuilding /From Lofting to Launching, to have a good overview of ONE of the methods (as JeffH suggests) that''s out there. The South African Naval Architecht Dudley Dix wrote an article for Woodenboat a year or so ago, I believe, about another technique he used in his backyard. Of course, if you''re talking epoxy, the Gougeon''s book on WEST-system cold-molded boatbuilding is also de rigeur. In any case, however, the theory is one thing, and the practice of it is another.