For a time, I believe in the late 70’s and early 80’s, an expanding foam was poured into the bottom of the hulls to serve as flotation foam in case the hull was holed. This was to prevent sinking. Unfortunately, it was not closed cell foam and it would soak up water.
I purchased my second SeaSpray (used) in the mid 80’s. This boat was in excellent condition but I noticed that it seemed sluggish compared to my first boat. It also was a great deal harder to manhandle when loading onto the trailer or pulling up on shore. I had also noticed a steady drip from the drain plug holes after the season ended due to my storing the boat with the trailer tongue elevated. I looked into the drain plug hole on one of the hulls and noticed that there was foam laying on the bottom of the hull and I suspected there was water in the foam.
In discussion with other sailors I begin to feel that something had to be done as I was going to compete with this boat. I decided to remove the decks and take the foam out. After removing the decks, I used a metal spatula or putty knife and started to cut into the foam. (I would recommend using a face mask and safety glasses.) I put the foam into a garbage bag and continued to dig, cut and scrap out the foam.
It wasn’t long before I hit foam that was saturated with water and after all the foam was removed from both hulls, I weighed the garbage bags and the weight came to nearly 50 pounds. I also cut a hole into the bottom of the structural ribs to let water drain easily through the hull. This is help to remove water normally held back by the ribs. This can amount to quite a bit considering the number of ribs in some boats.
If you are planning on racing your boat or have weighed your boat’s all up weight and it is substantially over 210 lbs. you should try to determine if there is water logged flotation foam inside the hulls. The boat I took the foam out of was still on the heavy side, being slightly over 200 pounds but nothing like the 250-260 pounds it weighed before I removed the soggy foam. (Note: Class rules state a minimum weigh for the boat, fully rigged, to be 185 pounds - you should be aiming for as close to that weight as possible if you plan to race.)