Mark, how did you calculate the amount of foam to make your boat
positive flotation? thanks bruce--M/V CINNABAR

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1. Positive foam floatation.  This feature costs a lot of
   storage space, but is inexpensive.

2. Heavy ballast for ultimate stability.  Pooh has 7000 lbs
   of ballast in a loaded displacement of 33,000 lbs (22%).
   Most "passagemakers" carry 10% or less.  Cruising sailboats
   typically carry 35-45%.

3. Pilothouse is external to the watertight hull.  If our
   relatively large PH windows break out in big seas, we
   revert to a self-bailing cockpit by installing the hatch
   boards (hopefully before the damage).

Comfort in rough weather is something else again, as you
say.  We can get very uncomfortable in seas of 5' or so,
unless they are on the tail.

Mark Richter, Winnie the Pooh

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Bid and sell for free at http://auctions.yahoo.com

If I may...

Here's how we did it for Solstice, our nearly finished 50-foot custom motor
sailer:

1. Make a list of all the different kinds of materials used to build the
   boat.

2. Estimate how much weight for each kind of material, i.e. Lead = 12,000

3. Get an engineering book that gives you the density of materials, i.e.
   lead = 600 pounds per cubic foot (as best as I can remember)

4. Divide weight of material (12,000 pounds of lead) by density to get cubic
   feet of lead.

5. From the lead, subtract 60 pounds times the number of cubic feet to
   accout for the amount of lead that will be supported by water. (Yes, all
   matials have at least some "floatation")

6. The result of 5 gives you how much floation you need for the lead.

One cubic foot of foam with a density of 4 pounds will support 56 pounds.
Thus 12,000 pounds of lead div. by 600 = 20 cubic feet of lead.  20 cubic
feet * 60 (weight of water) = 1,200 pounds.  12,000 pounds of lead - 1,200
pounds = 10,800 that need flotation.

10,800 / 54 = number of cubic feet of foam; thus we need 200 cubic feet of
foam to support the lead.

After you repeat this process for each material on board, you'll have the
number of cubic feet of foam required for neutral bouyancy.  Add as much
enough additional foam as you can afford and/or fit into the boat to achieve
some positive bouyancy, and to account for errors in estimating weights.

Caution:  Only the designer of the boat can tell you how it will float when
filled with water.  (Could be upside down!)

Dennis Mills