Brian Whatcott wrote:
On Wed, 16 Nov 2005 09:03:09 GMT, wrote:
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 ?


Freezing water is 62.4 lb/cu ft. Say the foam weighs nothing.
You need displacement divided by water weight per cu ft =
34500/62.4 = 553 cu ft. Add 10% for luck = 600 cu ft.

That's two chunks measuring 6 X 7 X 7 ft. each.

If it was designed into the boat, it would be 13 cu ft per foot, or
about 3 inches thick around the hull and deck. This would also add a
lot of stiffness, insulation, collision protection, etc. However, if
you were doing it from scratch, you'd probably pick a much lighter
design - the Etap 46 is 27000 lbs while the Tayana is actually 42000.