I was looking at a site that showed a home builder's sailboat. He had some
plans, set up a frame on the ground and made a cross piece frame ..

He used plywood to sheath the boat. Epoxy on the plywood.

Two things ... when building a hull, do you first need a backbone,,,
keel,,, or whatever??

Another ,,, if you use plywood, can you glass over the ply and the ply
becomes a core?

On Wed, 28 Dec 2005 18:51:08 GMT, "Thomas Wentworth"
wrote:

Two things ... when building a hull, do you first need a backbone,,,
keel,,, or whatever??

Not necessarily since there are many different ways of building a
boat, but building a backbone and frame/mold is certainly a time
honored method.


Another ,,, if you use plywood, can you glass over the ply and the ply
becomes a core?

You can but you end up with a relatively heavy boat by modern
standards.

You can see the sequence I'm using at
http://home.earthlink.net/~derbyrm/Chebacco.html

The keel goes on after the bottom is epoxied to the bulkheads (but,
hopefully, not to the molds).

"Stitch and glue" is another scheme. It requires no building forms/molds
and any keel is added later.

Most plywood construction does have a layer of fiberglass on the outside
these days, but the glass reinforces the epoxy to preserve watertightness of
the wood, not the hull. It doesn't add any significant structural strength
to the hull. (To reinforce against mostly submerged logs and jetsam from
the container ships, one would have to add it to the inside of the hull.)

Roger

http://home.insightbb.com/~derbyrm

"Wayne.B" wrote in message
...
On Wed, 28 Dec 2005 18:51:08 GMT, "Thomas Wentworth"
wrote:

Two things ... when building a hull, do you first need a
backbone,,, keel,,, or whatever??

Not necessarily since there are many different ways of
building a boat, but building a backbone and frame/mold
is certainly a time honored method.


Another ,,, if you use plywood, can you glass over the
ply and the ply becomes a core?

You can but you end up with a relatively heavy boat by
modern standards.

Is plywood as heavy as steel? If you cover it with fiberglass?

For the backbone ... can you use wood that is put together rather than a
solid beam?




"Wayne.B" wrote in message
...
On Wed, 28 Dec 2005 18:51:08 GMT, "Thomas Wentworth"
wrote:

Two things ... when building a hull, do you first need a backbone,,,
keel,,, or whatever??

Not necessarily since there are many different ways of building a
boat, but building a backbone and frame/mold is certainly a time
honored method.


Another ,,, if you use plywood, can you glass over the ply and the ply
becomes a core?

You can but you end up with a relatively heavy boat by modern
standards.

Hi there,

I'm new in this group, haven't read all the archives, but why don't you
try this site:
http://www.bateau.com

boatplans and free boatplans, with some pictures of construction of
home build boats. (I have not connection or interests in that company).

Best regards B19

Nowhere close to being as heavy. Even with fiberglass, it's less dense than
water. (It floats.) Steel ranges from 7.5 to 8 times as heavy as water.
(It sinks.)

If you laminate the pieces with filled epoxy, it will be better than a solid
beam because you will get rid of the defects (knots, splits) and "cross"
them with defect free pieces.

Roger

http://home.insightbb.com/~derbyrm

"Thomas Wentworth" wrote in message
news:INDsf.1413$SW3.595@trndny08...

Is plywood as heavy as steel? If you cover it with fiberglass?

For the backbone ... can you use wood that is put together rather than a
solid beam?

"Thomas Wentworth" ) writes:
I was looking at a site that showed a home builder's sailboat. He had some
plans, set up a frame on the ground and made a cross piece frame ..

He used plywood to sheath the boat. Epoxy on the plywood.

Two things ... when building a hull, do you first need a backbone,,,
keel,,, or whatever??

Called a "strongback" it gives stability to the work. most boats need
something. even some stitch and glue boats need something to hold the shape.


Another ,,, if you use plywood, can you glass over the ply and the ply
becomes a core?


Caled "encapsulation" there should optiminally be three layers of
resin-soaked fibre to keep water out of the wood on a boat kept in the
water.

Thomas Wentworth wrote:
I was looking at a site that showed a home builder's sailboat. He had some
plans, set up a frame on the ground and made a cross piece frame ..

He used plywood to sheath the boat. Epoxy on the plywood.

Two things ... when building a hull, do you first need a backbone,,,
keel,,, or whatever??

Another ,,, if you use plywood, can you glass over the ply and the ply
becomes a core?



Bolger's "Instant Boats" (books and plans available from H.H. Payson, )
offer an easy construction method that does not require lofting (Look
into this if you plan to build a traditional boat -- means drawing the
plans full scale so that you can find the mistakes in the measurements
given in the published plans and so that you can make patterns for
actually building. Many first time builders get so discouraged in the
lofting phase that they never get to the actual building phase.) or a
strongback (the cross-piece frame).

BTW, traditionally, what you are calling a frame is usually called
"molds" (or "moulds"). In traditional terminology, frames are a
permanent part of the boat.

Thomas Wentworth wrote:
I was looking at a site that showed a home builder's sailboat. He had some
plans, set up a frame on the ground and made a cross piece frame ..

He used plywood to sheath the boat. Epoxy on the plywood.

Two things ... when building a hull, do you first need a backbone,,,
keel,,, or whatever??

Another ,,, if you use plywood, can you glass over the ply and the ply
becomes a core?



Bolger's "Instant Boats" (books and plans available from H.H. Payson,
http://www.instantboats.com) offer an easy construction method that does
not require lofting (Look into this if you plan to build a traditional
boat -- means drawing the plans full scale so that you can find the
mistakes in the measurements given in the published plans and so that
you can make patterns for actually building. Many first time builders
get so discouraged in the lofting phase that they never get to the
actual building phase.) or a strongback (the cross-piece frame).

BTW, traditionally, what you are calling a frame is usually called
"molds" (or "moulds"). In traditional terminology, frames are a
permanent part of the boat.