Hi Mark,
on Arcadian I had similar noise problems with her fiberglass masts. The solution I used was to wrap the mast at the deck opening with a 5mm thick sheet of rubber (about as hard as the rubber of a car tire); then I used a piece of braided rope of the right thickness to caulk the joint at the bottom of the hole through the deck; I filled the space between the rubber and the side of the mast hole with thickened epoxy ( a half and half mix of microbaloons and sawdust). I then waterproofed the joint with two layers of canvas bedded in silicone sealant. The result was no noise and a trouble free, waterproof assembly that is , I believe, still working well after six years . I never needed to remove the masts but it would be fairly easy to chisel out the filled epoxy and release the rubber collar in order to loosen the mast sufficiently to make removal easy.
I hope this is of some help.
David.