From what I have seen and read the pourable expansion foam is your best bet. Re deck your boat cut 2 inch holes and pour the foam in drop in the puck from the hole saw once foam expands then resin and tab it in. The expansion foam makes the boat stronger as it gets into all the crevices and it bonds to everything making your hull stronger and more solid. It also helps to deaden sound when the water is bouncing off a wake and into your boat.
