View Single Post
  #12   Report Post  
Hollywood
 
Posts: n/a
Default Diagonals in lofting

On Tue, 29 Jun 2004 11:24:47 -0400, DSK wrote:

Hollywood wrote:

Hi All,

I'm considering building my own boat from a set of plans. It's nothing major, just a 28'
round-bottomed cutter.


Yeah, that's nothing major. sarcasm off
Sounds like a great project. What design?


Really? I didn't think a 28 footer was that bad. The one I'm looking at is a Mark Smaalder's
design called a Wynfall.



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.


In that case, you should buy a boat rather than build one... since this is heresy for this
newsgroup, how about building something smaller & simpler that will get you on the wate sooner?


I've been think about that too but I'm in a kind of dilemma on that.

I have a great functioning 8' Walker Bay that's almost indestructible, so I don't need a dingy.

I would like something that I could stay on board for a period of time (possibly 3-8 weeks or
more at a time) without feeling too overly crowded. That kind of eliminates a day sailer.

Glen L Marine has a 22' Amigo but there are only stock plans and after talking with them, they
made it quite clear that the plans are printed in stone, no changes, no modifications.

I found Mark's page and though he does have a smaller version available, I do like the lines
and the construction method of the Wynfall better.



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.


Really? Where have you been looking? There are plenty such boats all around.


I'm in the Great Lakes area of Canada.

You can buy tupperware by the ton here but wooden boats seem to be in very short supply. I've
tried some boating sites (including Good Old Boat which does have some nice possibilities) and
tried to find online newspapers for the Canadian east and west coasts as well as Florida, but
finding a boat in the classifieds is just a little daunting.

If you have any sites, I would appreciate them.



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?


The diagonal is supposed to show that the body plan is "fair" ie a smooth continuous surface,
hopefully capable of having planks laid along it without humps, shoulders, or needing to steam the
planks to the rigidity of week old spaghetti.

Now how does it show that? Is the diagonal at 90 degrees to the frame at that point? I guess
that's what is confusing me. The buttocks are parallel to a line along the length of the keel
and the water lines are parallel to a plane at the base of the keel and perpendicular to it,
but what is the source of the diagonal? At what point does it show me a fair hull? Both the
buttocks and water lines show some sort of profile where you could pick up points for the
frames to lay down on the lofting floor but the diagonals don't seem to show more than a point
at a specific spot.

If this sounds confused, it because I am.


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,


From a lumber supplier that has boatbuilding wood.

There's Noah's in Toronto but it seems to thin out fast after that.


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


Bend the frame tight against the inside of a set of ribbands.


?!? Shows you where I'm at. I was under the impression that the frames were bent on molds, then
placed inside the ribbands.

You need to sit down by the fireside with a copy of Howard Chappelle's book 'Manual of Wooden Boat
Construction.' He covers it all in detail, yet clearly. Be sure to read the part about needing a
Moaning Chair


Actually, I must be denser than lead because I have been reading Chappelle as well as Larry
Pardey (now that's the kind of boat I'm talking about) and while they both talk a lot about
diagonals, they don't really explain where they are getting the information to lay it down or
where the staring points are.

Fresh Breezes- Doug King


Thanks Doug