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John Holtrop
 
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Default Diagonals in lofting

regarding the value of diagonals, they give the designer another set of
points, which are useful for evaluating the fairness of the hull,
particularly around the turn of the bilge.

"Hollywood" wrote in message
...
Hi All,

I'm considering building my own boat from a set of plans. It's nothing

major, just a 28'
round-bottomed cutter.

I know, build a dingy first to sharpen my skills, then build the big one.

Problem is, life's
getting on and, with the reaper peeking at me from over the next hill, I'd

like to get out and
do some sailing before he sits down with me.

I would try to buy one, but it would seem the rest of the world has never

heard of a beamy
24-30 foot wooden cutter with a transom hung rudder and a full keel using

lead as ballast. So
here I am.

I do understand most of the lines used in lofting with the exception of

the diagonal. What
exactly is the diagonal supposed to show me?

While I'm at it I might as well ask about frames. The plans call for steam

bent frames because
it is supposedly faster, cheaper and takes up less room than sawn frames.

I have a few problems
with this. 1) Where is one supposed to get the clear wood for the frames,

2] Bending a frame to
an arch isn't much of a problem but how do you bend it to match the curve

laid out by the
intersection of the water lines and buttocks (i.e. the angle described

gets more acute the
closer to the bow at the sheer but will be flatter on the same frame close

to the keel. This
can be done on a sawn frame by changing the angle of the bandsaw table as

you cut the frame).

Thanks for any help,

Frank