Considering installing flotation foam under floorboards in my 20ft Wooldridge Sport. I want this boat to absolutely not sink even if fully swamped in the ocean. Basic idea is use screwed in place aluminum channel or rectangular tube to raise floor boards 3" and then fill all voids with extruded polystyrene boardstock insulation (does not absorb water). By my calculations, rasing the floor boards 3", and after accounting for lost space due to gas tank and structural members, would net me about 42 cubic feet. Boardstock weighs 5 lbs/cubic foot so net bouyant uplift force would be 2400 lbs which is about 240 lbs more than boat, main engine, kicker, anchor etc..... Fuel floats so any empty space in the fuel tank is a bonus. I am pretty confident in my math and measurements, so the question is:
Anybody done this themselves and have any pointers?
Any speculation on if the handling of the boat would change noticeably due to lifting the floor boards (and thus any weight inside the boat) by 3"?
Glen Wooldridge told me DO NOT pour foam it because pour foam water logs over time, and will trap water and then cause problems when the trapped water freezes in your driveway in the winter.
The other option is foam in the side trays and under the existing floor boards, but then you lose all that storage
The other option (much easier) is to foam under the existing floor boards, and also completely foam under the bow.
It was interesting to learn that only boats 18ft or less are required to have flotation, and the actual test procedures for "full level flotation" are not very well defined, i.e. with or without engine? with or without typical bolted on or entrapped objects in storage space typical on most boats?, loss of bouyancy over time due to foam water logging? Boats over 18 ft are not regulated and each manufacturer comes up with their own criteria for what they think flotation means when or if they foam their larger boats..............