The idea of a big bulky 1-1/2 to 3" thick extra hunk of foam up in my v-berth just didn't seem like a good idea.
I brought my 5 bed cushions home and one-by-one pulled the staples and removed the covers. I used my electric (meat) carving knife and shaved off about an inch of the original (concrete) foam rubber. It started out easy but if got to be a bit of a fussy job. If I had to do it again I would have stripped it all off and replaced it with a slab of 1-1/2" regular foam. Anyway, once I got it shaved down, then I applied a topper of 1-1/2" memory foam. Used spray adhesive. Then I re-covered the cushions with the original cushions. The "new" v-berth looks just like the old v-berth and is much more comfortable.
I had debated using an entire 3" thick slab of memory foam but I experimented with a 3" sample and it compresses completely down to the plywood. Not good. And, just an opinion, I think as you sink down into the foam it would get too warm. Not the best idea for summertime boating.
One other thing. The princess demands sheets, especially a bottom sheet, instead of the thin fleece zip-up sleeping bags. Fitted sheets seemed expensive and struggling up in the v-berth area tucking the sheets in all around just never seemed to work. So I got some of those plastic snap buckles and attached them to the perimeter of the v-berth cushions on short straps. When installed on the boat, they just peek out from under the bolsters. Then the bottom sheet was cut down to size and I sewed the matching buckle pieces to the sheet with a short bit of strapping. These pieces are adjustable so the sheet can be adjusted taught. It worked great on the family room floor. First tryout on the boat is next weekend.
