"Brian D" wrote in message
news:y_rpc.54753$xw3.3275430@attbi_s04...
In the book Devlin's Boat Building, Sam Devlin states that boats over 90'
have been built using these methods.

Brian

When I think of Plywood composite boats I think of plywood as the core
material for a fiberglass lay up. Plywood is stronger than most cores and
this strength is probably use in the structure of the boat so it is
important that it remain dry an rot free. Not easy things to do over a long
period of time. As long as it retains its structural integrity you can dry
out cores by drilling holes ever few inches and vacuum bagging the hull
until is stops loosing weight. The hot summer sun will help.

As a core material plywood is a pretty good one it is inexpensive, strong,
reasonably easy to work and not subject to catastrophic failure that plagues
some other core materials when they encounter slamming loads.

Even better is veneer that can be treated with a borate solution to rot
proof it and laid up with epoxy to water proof it for a lighter, stronger
more expensive and more durable core.

Gordon

Is there a source(s) I can go to to learn how to treat a veneer with a
borate solution?

"Gordon Couger" wrote in message news:yMNpc.31057$bS1.19364@okepread02...
"Brian D" wrote in message
news:y_rpc.54753$xw3.3275430@attbi_s04...
In the book Devlin's Boat Building, Sam Devlin states that boats over 90'
have been built using these methods.

Brian

When I think of Plywood composite boats I think of plywood as the core
material for a fiberglass lay up. Plywood is stronger than most cores and
this strength is probably use in the structure of the boat so it is
important that it remain dry an rot free. Not easy things to do over a long
period of time.

Good thinking: Devlin designs plywood boats glued together with epoxy
and glass. Plywood cored boats with epoxy/glass skins are very
different. It is correct that in small boats, we use the properties of
the core. It is an hybrid material, between plywood and sandwich.
About large ones: once you get to 25-28', a foam core is a better
choice. Lighter, stronger, no risk of rot.
That is why se stop using plywood in that size range.

Jacques from bateau.com

Lighter, stronger, no risk of rot.
That is why se stop using plywood in that size range.

jacques, boats with balsa cored decks virtually ALL become squishy soft over
time. boats with plywood cored decks almost never do, and those that do, do so
only in small areas. plywood cored decks are almost as long-lived as solid
fiberglass decks, and weigh less.

Have heard repeatedly from highly experienced, long term naval architects that
plywood hulls covered inside/outside and between plywood sheets are stronger
pound for pound than most any other material out there. About the only thing
that beats ply is damned expensive composites.

Very few plywood boats out there, though. People think they are wood and
therefore won't build they from scratch and won't buy used ones.

JAXAshby wrote:
jacques, boats with balsa cored decks virtually ALL become squishy soft over
time.

This is as true as anything else Jax posts.


Have heard repeatedly from highly experienced, long term naval architects that
plywood hulls covered inside/outside and between plywood sheets are stronger
pound for pound than most any other material out there.

That must explain why all the America's Cup boats are built from plywood.


Very few plywood boats out there, though. People think they are wood and
therefore won't build they from scratch and won't buy used ones.

Yep plywood boats are so rare that they are really a tremendous novelty.
I bet that nobody here knows as much about building boats from plywood
as *you* do, Jax!

DSK

dougies, so sleep it off

JAXAshby wrote:
jacques, boats with balsa cored decks virtually ALL become squishy soft
over
time.

This is as true as anything else Jax posts.


Have heard repeatedly from highly experienced, long term naval architects
that
plywood hulls covered inside/outside and between plywood sheets are
stronger
pound for pound than most any other material out there.

That must explain why all the America's Cup boats are built from plywood.


Very few plywood boats out there, though. People think they are wood and
therefore won't build they from scratch and won't buy used ones.

Yep plywood boats are so rare that they are really a tremendous novelty.
I bet that nobody here knows as much about building boats from plywood
as *you* do, Jax!

DSK

(JAXAshby) wrote in message ...
dougies, so sleep it off



Jax,do I have to report you to Opalcat again?
;-)
FIY:
http://fathom.org/teemingmillions/jax.html

Jacques from bateau.com

http://fathom.org/teemingmillions/jaxascii.html

That's just disturbing.

Jacques wrote:
(JAXAshby) wrote in message ...

dougies, so sleep it off




Jax,do I have to report you to Opalcat again?
;-)
FIY:
http://fathom.org/teemingmillions/jax.html

Jacques from bateau.com

--
Matt Langenfeld
JEM Watercraft
http://jem.e-boat.net/