Not a simple calculation. Note that the loads go in all directions; up when
at rest, but down when you've buried it in a wave and athwartship when your
jib is pulling on a broad reach.

Do you have a forestay on your mast? Are you going to keep it? If not, how
are you going to transfer the load back to the hull. That forestay is
(arguably) the hardest working line on the boat.

Classically, the heel is buried in heavy timbers, the "partners" (knight
heads) at the bow pick up the side loads, and the gammoning holds it down.
The latter is aided by stays down to the hull. I'd suggest that 1" siding
is too little. You might see if Dave Gerr has anything to say about
bowsprits in his "Nature of Boats."

It's also normal to make provision for unstepping the bowsprit since it gets
damaged easily and the boat fits into storage spaces better without it.
(I'm not sure what you have in mind when you say "all laminated and screwed
together.")

Roger

http://home.earthlink.net/~derbyrm

"ahoy" wrote in message
...
Hello, I'd like to add a 4' bowsprit to an IP23 sailboat. To what
extent does the bowsprit rely on the rigging for it's strength vs it's
actual strength of materials? I was hoping to use a one inch thick
piece of epai 6 feet long, two feet on deck, four feet for the
bowsprit and 2 more 4' long, one inch thick planks butting the bowstem
all laminated/screwed together. About 3 1/2 inches wide with two side
stays and a 5/8" stainless rod for the dolphin catcher and a stay to
the masthead. I'm looking for some advice as to whether this is too
much or too little. Is there a better place to ask this question or
get some information? Thanks for your time.