These guys were mostly interested in stiffening up the dish-panning deck, even though they misused the term of buoyancy. I was very amused at the end when the guy wiggled back and forth with the boat in the water saying how much better the boat felt because until the open cell foam absorbs a lot of water, the boat only weighs as much more than it originally did by the net weight of the 12 cans of foam they put in it. They clearly misunderstood the concept of buoyancy.
Boston Whaler developed their legend while designing into their radically new cathedral hull boats the added weight of the closed cell foam. They are indeed heavy boats for their size. They did not add "buoyancy." They simply eliminated the empty places previously filled with air where water could fill the space with buoyant foam.
I am an old Navy trained salvage officer, and I know from buoyancy. I am most amused with this one. Glad somebody posted it.