Gecko,as long as you have the right attitude about storage
(or lack thereof)and you can find enough volume to put the foam its probably doable,i dont see a problem with stability on a ballasted keel
boet,if it were unbalasted then you would need to place it higher up. I agree with Sandy on reclaiming some of the Storage but i wouldnt use just air. On my Cat it was filled with foam blocks all the way up to the deck
ahead of the fwd crossbeam and aft of the aft beam,but the areas under the berths were the only potential storage spaces in the long skinny hulls and were entirely filled with foam so i removed the berth tops and some of the foam installed large plastic tubs from home depot with the top flanges flush with the underside of the plywood
tops,they were well supported by foam under them and through fastened to longutudinals,when i put down the new tops they were filleted to the hull
and glass taped and glued to the tub flanges with 5200,i then installed Bomar
hatches which have o- ring seals
and 2- t handle latches
and are completly watertight,they protruded about 1/2" above the berth so i glued down 1/2" ensolite over the rest of the top so you didnt feel the hatch
under the cushion.It was a lot of work but i gained back a lot of storage without losing floatation,it is tricky fitting the block foam but i filled any voids with styrofoam packaging peanuts.
Even though i have used it on my other boat i am not as confident in the expanding foam,ive seen way too much of the coastgaurd approved stuff under the cocpit soles of small powerboats that is completly waterlogged,what i have come to believe is that as it expands and cures it forms a hard skin that is waterproof and as long as its not compromised its ok but when it is it sucks up water
like a sponge even though its supposed to be closed cell. Styrofoam on the other hand will not absorb water
and i would trust my life to it.I have seen on other threads where people claim it will but they are wrong,they sell the stuff in large blocks called dock
billets and they sit in the water unprotected for years supporting docks without absorbing water.I have heard of people using plastic pop bottles and thats the only way id trust air but they may be a little hard to use but may be ok.