Jim,
Our fleet has acquired an Ensign that is way beyond our capability and budget to restore. I have been thinking about removing the rotted deck over the bow and stern to expose the flotation cavities fore and aft in order to use it as a mold. I would apply a mold release wax to the interior surface and then pour in Total Boat's liquid two part expanding foam flotation. After it cures, it could be cut up into blocks of manageable size to fit through an access hole cut in the forward and aft bulkhead and they would fit the contour of the complex curve of the hull.
This Spring I replaced the flotation in my bow cavity through an opening I cut in the forward bulkhead. I cut blocks from the 2 inch foam board sold at Home Depot. However you really can't get a tight fit because the hull curves and the foam board is flat. I hope to attempt this experiment using a mold to create properly shaped blocks later this summer.
Pete Kogut
The White Lady #856
Fleet 23