If its waterlogged its not going to dry out without pulling the floor, and even then it will most likely loose some of its floatation properties. Many years ago I had to pull a floor out of a 16' Mon-Ark because it was saturated for about 6 months. During that time it had already started to grow mold and funky bacteria, it was totally ruined and was unsalvageable and had to go. I found replacement flotation from a guy I knew that worked with "spray on insulates". You can find the same type of stuff in many home stores and on-line. Spay it in and it will expand into all the contours and crevices of the inside of the hull, then trim to fit the floor back in. You can also spray it into the sub-floor area after the floor is in place and it will expand throughout unless there is a barrier there to stop it. Personally I would figure out a way to remove saturated floatation one way or the other, no flotation is better than saturated floatation.