Just a thought, but if you can get to them I think i would try to get some Marine expanding foam or an equivalent, and try to get some under the blocks or on top. You will have to be careful not to use too much because there could be a hull distortion if you went crazy. 3m makes an automotive product that is two part, it is a non structural pillar foam that is used for noise reduction. Because its non structural there would be very little chance that it would cause any problems. It dries to a soft squishy foam that is water proof or resistant.
|