Paul,
Nice to see more work on your Commander. From your work description, it appears your attempting to restore the void in the lazarette locker with a similar foam (like original). If so, do not use the foam that comes from a can, like you can purchase from a hardware store. That is the wrong type of foam for this application. A more fitting type of foam and what you should use is a two part firm floatation foam, that after the two parts are mixed, can be poured into a cavity and it will expand and fill the void. The type of foam that I'm referring to is rigid polyurethane foam. It is USCG approved and a quart kit yields approximately 2 cubic feet. Do some research. With the amount of work your doing, might as well choose the right foam for this.
Thanks for posting the photo. Also, it's referred to as forestay or in some conversations a headstay, not frontstay, though I know what you meant.
Respectfully,
Chance Smith
(Formerly) Sea Sprite 23 #760 (Heritage)
(Formerly) Commander #256 (Ceili)