I took the time this morning to call Andrew and get some perspective on where he is coming from on this and now I understand a bit better. His operating environment is Naraganset Bay and he and Morton face some very nasty conditions there that I can avoid where I hunt if I need to go out on a marginal day for a weather call. So I see why he wants info on real world bad water conditions and flotation in a down flooding situation.
I still feel that the two factors that foam has as a plus, outweigh for me the drawbacks, if the boat is of the type that Dave built or for that matter the boat Andrew built.
These are first, stiffness or resistance to deflection of both the outer hull skin and the inner floor. Second, the ability to provide additional buoyancy after a hull strike that punctures a hole over 2 inches in diameter. No pump in this size boat will keep up with that.
As for the draw backs they can be real and must be understood so they can be dealt with if they come up. If allowed to stay in a saturated condition the foam will absorb water and get heavy. Also it will provide a problem for the wood\epoxy hull in time. I see this as a fixable condition if the floor is taken up and the foam replaced if it were to get wet. Dave could do it in less than two to three days if my observations are correct on his work pace.
Some will not find this OK and that is fine for their situation. But I see wood as a much easier working material than AL for boats in this class, and much less costly to buy even if you include the epoxy and cloth unless you are in the metal buiss. and are a good welder as well.
But I will say, I look at boats like refrigerators or washing machines. The industry is designing them for about a 6 to 7 year life cycle, but with maint. you can easily get double that. I work on boats and dont see a problem with having to do work on a hard used vessel to keep it up to standard.
On the issue of foam acting as a righting moment I believe it does not apply here in these type of low Center of Gravity , high width to length ratio small vessels. If you had a built in structure or taller hull form that brought the CG up I would be more cautious. These boats dont have high T tops or high side wall structures to push the CG up and create the problem.
For the conditions they hunt in I am not kidding when I say a design like the Motor Life Boats would be where I would look for cues for design.
http://www.pbase.com/roberthouse/cg2007
http://www.cg36500.org/restoration.html
The Banks hull form is close to what I think of, with the rounded Higher Sides to provide Massive reserve buoyancy in a leaning condition. The top of the rounded area would have to be closed off and water tight though, like a decoys back. At that point I would consider weight down low to help the flipping concern but it most likely would not be necessary with loaded gear secured to do the same job. But I don't want to hunt out of a boat big enough to include two large sealed spaces required to handle a flipped over situation (Think mini coast guard surf boat).
Also the chance of finding an outboard that will make SOLAS roll requirements for running after a full rotation makes it more complicated.
None of my thoughts on foam under the floor means I would not want it also up high as in bow and stern compartments just as Dave built into his boat.
I told Andrew I thought Dave did a heck of a job with his demo and Andrew owed him a beer and a well deserved concession on this particular boat point.
Ill make the chowder.
Todd,
you still got me laughing, and I will keep my kids from reading the F bomb part.
