I'll bet that almost anyone who's built a boat or two can do this for you.

You can actually do it yourself if you have an hour or two. Different folks

like different things to sit on. For me, the wedges and the foam pillows

(such as "Happy Bottom") don't work at all well; they cause that

circulation cutoff you're experiencing. Many people feel perfectly

comfortable using only a 1/2 inch simple foam pad on the bottom of their

boat. But it's really easy to make a custom-molded seat which fits your own

rear end, starting with a block of good quality closed-cell foam. I like to

glue up a block about 16 inches by 16 inches, 4 inches thick, sit on it,

mark out where my "sit down bones" were, and start carving.

However - I know that many excellent seats have been made starting with a

12 X 12 inch piece of 3 inch thick foam, and that's much less trouble to do.

These seats are carved in a sort of ellipitc bowl configuration, leaving a

**slight** ridge in the center. Especially for men, be very careful not to

leave more than a very slight ridge; otherwise you run the risk of the

"bicycle seat phenomenon" which can cause some permanent health problems.

The sides of the bowl never get vertical, but maintain an outward-sloping

angle from the center, so your hip bones are gripped securely but not

painfully tight. The depth of the bowl is such that only about 1/4 to 1/2

inch of the foam remains on the thinnest parts of the bottom when you're

finished. If you go all the way through the foam, no worries - just glue a

1/4 or 1/2 inch thickness of foam on the bottom and feather the edges of

that on the underside of the seat.

The reason for starting out with a 16 X 16 inch piece of foam is that it

gives you the opportunity to maintain a 1 or 1 1/2 inch lip of foam around

the edges of the completed seat, and to extend the seat forward a slight

bit if you want to - but be careful not to leave a lip of foam at the front

edge of the seat, which could push up into your thighs, of course.

Do this carving outside. You'll be amazed at the volume of tiny bits of

foam "sandings" you generate, and you'll be very frustrated at how

difficult it is to clean them all up if you do it inside. The foam sandings

mixed with Cabosil or Microlite or silica microballoons make a good light

thickener for end-pours and so forth.

The block should be secured to something else, like a piece of scrap wood

which you can kneel on, because if it's unsecured it will tend to fly or

spin all over the place as you carve. Use several small bits of hotmelt

glue to secure the foam block, then just cut off or melt the little blobs

of hotmelt when you're done. Carving can be done with several different

things; the easiest, I think, is a heavy gauge disc of wire brush, attached

to a variable speed rotary drill or a small handheld grinder, used very

lightly and very carefully. A broken-off piece of Sureform plane works. The

serrated edge of a diving knife works. And so on. "sharkskin" or a 40 grit

emery paper is nice when you're all finished carving, to give a relatively

smooth edge.

If you like esthetics more than usefulness you can cover your seat in

stretchy black cloth like the cloth which is sold for loudspeaker covers -

but I prefer to leave the seat just "as is".

The finished seat can be secured in your boat with Velcro (try to get the

marine version), or contact cement. I like to use Velcro until I'm certain

just where I want the seat to be.

Bill Hansen

Ithaca NY