Quote:
. . My first concern was that it might cause an osmotic problem but since air freely covers both outer surfaces I don't believe it to be a problem. I'm going to try it around the chase where the fuel vent and gas fill goes.
|
Tom, don't do it! "Better" is often the enemy of "good enough"! You CAN get osmotic blisters on the inside if that foam gets wet and holds water. In fact, since there is no gel coat on inside, it can blister from the inside easier than outside! I'm convinced that foam in boats is generally a bad idea because it can add a lot of weight if it gets wet!
The early SeaCraft's had NO foam in them! It was only added when the USCG started requiring positive flotation in the late 60's. Any foam in a Moesly or Potter SeaCraft is only there for flotation, none of it is structural.
Like Connor said, Moesly knew what he was doing and tried to put the beef only where it was needed. He was a pilot in WWII and with over 13000 hrs in all types of planes, and spent about 15 years after the war converting surplus aircraft into executive transports. He understood aircraft construction, how much weight hurts performance, and his boats reflect that understanding. His philosophy was to build it very stiff but as light as possible, and then take it out and beat the hell out of it (in the offshore powerboat races in the early 60's) to see if anything broke. Nothing broke, and he literally blew away all the competition in his class for several years!
If you'll study the Boating Magazine article on the Seafari 20 in the Literature section, particularly the cross-section showing the stringer arrangement and the lay-up schedule, you'll see that Moesly truely was a genius when it comes to designing a stiff light hull. The 4 stringers were put in about half-way thru the lay up, so they're an integral part of the hull. The bottom panels are naturally stiff where there is a vertical step, and the stringers are attached near the center of the panels to provide extra thickness and stiffness where it's most needed. The inner liner (consisting of about 1/8" glass + 1/2" balsa core + 1/16" glass) is then bonded to the top of the stringers, creating an I-Beam that's about 12" tall! This structure is so robust that Potter was able to change it from 4 to 2 wider box stringers in about 1973 with no ill effects, evidently as a cost-savings change. Because of this design and construction, hull failures are virtually unheard of in a SeaCraft. The weakest link on these boats is the "Nut on the wheel"!
About all you need to worry about is an ignorant previous owner that may have drilled holes in the cored deck, gunnel or transom without proper sealing, allowing water intrusion that will rot the core. As long as those areas are solid, you're good to go! Denny