Hi,

I've been doing a lot of thinking recently about building a sloop
with classic lines. It's not the first time this has crossed my mind
but the idea just will not remain dead.

I recently replaced the cockpit sole in my 'classic' soling and
upgraded the sail controls. Now the crew only moan about my driving
and not about putting their feet through the floor or the condition of
the sheets.

While working on the sole I did some investigations into having
plywood CNC milled. It's not that expensive! I also prefer engineered
wood to natural timber.

With this new found info my mind quickly raced into overdrive. In
theory it should be possible for me to design and build a carvel hull
from plywood without me having to do much more than glue and clamp, no
measuring no cutting, think lego not woodwork.

Here's the way I'm thinking.

Alignment. If two pieces of plywood are to be joined then an
accurate means of locating them needs to be done. I'm thinking the use
of dowels with the holes reamed on the CNC machine. Two dowels would
locate any join.

Scarfing. You can mill the 12:1 ratio into the plywood along with
the alingment holes for dowels. Epoxy the scarf insert the dowels and
clamp.

Keelsome, ribs, beams etc. These could all be made from laminates
pre milled on the CNC. Again epoxy, dowels and clamp.

Planks. Scarf joints as above. Rabits milled. Even the holes for
rib screws could be pre drilled/counter sunk on the CNC machine.

If all the majority of the time building a fair hull is spent in
the measuring cutting stages would not the above method produce a such
a hull in less time than other methods. Also it would be easily
repeatable.

I think I've given enough details for people to get the idea. Now
what is obviously wrong with this idea? Does anybody have existing
examples?

Hi

It is very nice to be able to mashin various things in plywood, my
experience though is that the most important issue when building a boat
are the framework. Check this link to find a very different attitude
towerds what make the foundations to place the panels upon.

http://groups.yahoo.com/group/Cyber-Boat/

P.C.

On 24 Jul 2005 04:55:46 -0700, "
wrote:

Hi,

I've been doing a lot of thinking recently about building a sloop
with classic lines. It's not the first time this has crossed my mind
but the idea just will not remain dead.

I recently replaced the cockpit sole in my 'classic' soling and
upgraded the sail controls. Now the crew only moan about my driving
and not about putting their feet through the floor or the condition of
the sheets.

While working on the sole I did some investigations into having
plywood CNC milled. It's not that expensive! I also prefer engineered
wood to natural timber.

With this new found info my mind quickly raced into overdrive. In
theory it should be possible for me to design and build a carvel hull
from plywood without me having to do much more than glue and clamp, no
measuring no cutting, think lego not woodwork.

Here's the way I'm thinking.

Alignment. If two pieces of plywood are to be joined then an
accurate means of locating them needs to be done. I'm thinking the use
of dowels with the holes reamed on the CNC machine. Two dowels would
locate any join.

Scarfing. You can mill the 12:1 ratio into the plywood along with
the alingment holes for dowels. Epoxy the scarf insert the dowels and
clamp.

Keelsome, ribs, beams etc. These could all be made from laminates
pre milled on the CNC. Again epoxy, dowels and clamp.

Planks. Scarf joints as above. Rabits milled. Even the holes for
rib screws could be pre drilled/counter sunk on the CNC machine.

If all the majority of the time building a fair hull is spent in
the measuring cutting stages would not the above method produce a such
a hull in less time than other methods. Also it would be easily
repeatable.

I think I've given enough details for people to get the idea. Now
what is obviously wrong with this idea? Does anybody have existing
examples?


This method is apparently in use for plywood kayak kits, all
beautifully precut into numerous swaths for multi chine hulls.

So the problem is not practicallity I don't suppose - but rather
commercially worth while volume.

Brian Whatcott Altus OK

If it works for plywood panels it should also work for fibreglass panels,
aluminum panels, and steel panels - any sheet goods. Where do the panels
get the strength to hold the shape of the hull?

--
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Hi William,

the laminated ribs should provide the shape of the hull, just the same
as traditional plank on frame construction.

Hi Brian,

I don't have any plans to do this commercially. But for home
construction it would be nice to complete a hull in a more timely
manner than is currently possible.

Hi.
With small hulls you most often can rely on the panel strength , you
hardly need any ribs and having no ribs also mean that you can't make
the most important part in terms of creating structural strength, --
the stringer.
But at some point with just some size boat hull, you will need the box
structure at some point you can not rely on only the "strength" of the
panels, you need a few stringers ,an extreme strong part of the boats
structure , then the box structure follow the shape of the hull as it
is made panel-rib-stringer. A 3D-H framework are making it all into a
box structure.
Now if you are not to build the hull anyway, you can say whatever you
want, --- but if you realy want to do reliable works drawings, you need
to know and understand the feature that nomatter what modern material,
are the fundamental part of it -- the box structure created as soon you
strongly attach a stringer. Now you can make all the most fancy
drawings you please, but fact is, that when you understand the
fundamentals , what make the hull, from a shivering collection of
panels, into a rugid structure ;-- with the 3D-Honeycomb you both
avoid the lofting and get a set of frames that will form just any shape
keep that shape while you slot assemble the frames so each frame are
allready from the basics , supporting and supported by all other
frames, one huge collection of ready to cover cubes, and at the same
time, when you cover inside and outside with panels, you get a boat
hull capable of twisting , something that only add speed btw. a sort of
strength that is very important for a boat hull ,
The most important issue building from panels and frames are, to have a
reliable framework to attach the panels, a framework that will not bend
or move, a 3D-Honeycomb framework produce just that, produce an extreme
strong framework for any shape hull. ------ insert a 3D model of the
engine ,subtract that from the 3D model and when frames are cut and
assembled, the engine bed are there allready.

P.C.