Re: Fast Motorsailer mods
- --- In email@example.com, "Nels" <arvent@h...> wrote:
> Good for you two. I will be following your progress with a greatdeal
> of interest. Take lots of photos for the visual folks, and makenotes
> for us cerebral types;-) Maybe do an article or two for Duckworksmag?
> Have you run all your proposed changes past the Boss? NO I mean
> OTHER BOSS - Susanne:-)is
> I am sure they would have no objections, to any of the changes, it
> just that they may have some even better ideas.Yes, I did tell Phil (in a fax) about the mods we wanted to make but
> All the best, Nels
at the time he said that they didn't have the time to do them due to
other ongoing projects. At that time he didn't say anything about
better ideas but did send me 2 pages about sail plan mods that
someone over in Germany had done. Since we aren't too interested in
the sail part of motorsailer we are not getting the extra plan pages
Based on the fact that the hull is fairly straight sided and doesn't
curve too much, I don't think it will be too hard to add in the
extra length right in the middle to keep the center of gravity
moment near the same.
Part of my job when I was in the Air Force as a Boom Operator was
computing the CG of the KC-135's that I was flying on. In those
planes we had about 39" from forward to aft center of gravity limits
that we had to stay within.
Find the center of gravity, split the hull there, move the two
halves three to five feet apart, add in an extra frame (or two),
cover with plywood, tape and epoxy the seams.
I know it will be more complicated than that, but that should be the
- Not trying to put you off, Ryan, but here is another consideration:
without increasing scantlings (thicker ply on the bottom?), will the
boat be strong enough with the extra section added? Five ft. is a lot
in a boat this size. Think of the forces at work when the hull is
supported in the middle by a wave, particularly if that wave is
moving at 20Kt or so. The trouble with flat sheets of plywood is that
they are not as rigid as sheets that are curved. There might not be a
problem unless you are using a large engine. PCB would have the
--- In firstname.lastname@example.org, "Ryan Cermak" <RCermak@t...> wrote:
> Find the center of gravity, split the hull there, move the two
> halves three to five feet apart, add in an extra frame (or two),
> cover with plywood, tape and epoxy the seams.
You need to think about (and possibly calculate) whether the hull
will trim correctly, at rest and while planing. You will be changing
the weight, the buoyancy and the dimensions of the planing surface.
With aircraft, I don't suppose you need to worry too much about
hydrostatics, or the hydrodynamics of planing surfaces either, except
with seaplanes or flying-boats.