DSK wrote (in another thread):
Actually, I think it would be a good project to add positive
flotation to any cruising boat that ventures out into big water.
Some care should be taken with the volume distribution , so that
stability is mainatained, as well as ensuring sufficient volume.
You could utilize the interior angles & odd nooks so as to not
lose too much stowage.

How do I figure out how many cubic feet of foam I need to add
to a 46' Tayana Pilot without filling it with water ?

Hull: Fiberglass
Displacement: 34,500 lbs
Ballast: 11,000 lbs

For more details see http://www.tayanayachts.com.tw/V460.htm
and http://tayana46.tripod.com

It has a watertight bulkhead in the bow and a large storeroom
(lazarette) in the stern. Do you think it would be enough to just
put the floatation blocks in these areas ?