"Lawrence James" wrote in message thlink.net...
The point of my link to the article was to support my statement that
polyester resin is not water proof. You won't find that I have suggested
that foam core is a good idea. I recognize that salt water can act as a
preservative. But what I see is that many boats are built with plywood. In
the floor and transom. Some even use encapsulated plywood for stringer
grids. Many will get wet from rain water, not sea water. Not all, but
plenty of them will evetually suffer rot in these areas. So I see nothing
good about using plywood to build fiberglass boats.
================================================== =========

The reason for using wood is to add stiffness to the structure without
adding excessive weight. Wood is much stiffer than fibreglass and
weighs less than half as much. The trick is to use the very best
quality plywood and to make sure that it is well encapsulated. Good
quality marine plywood can withstand years of a high moisture
environment without deterioration of any kind. The problems arise
when builders cut corners by using ordinary construction grade ply.
Unfortunately that's a common practice at the low end.

Sorry, I don't have a panacea. When I replaced my plywood grid stringers I
used 5/4" composite desk boards on edge. I liked them, but they were heavy.
Subjectivly it seemed they had a little more flex that an equal piece of
wood but I layed them in with epoxy and glass cloth so I think they ended up
rigid enough. Encapsulating foam clearly sucks. I have heard that a few
companies are using vertical pieces of fiberglass alone as stringers.
Transom has to be something besides just fiberglass though or it will be too
heavy. I don't think metals are the answer because I suspect there would be
adhesion problems. Not sure about that starboard stuff, perhaps that would
be a good transom material. I'm only certain about one thing and that is
there has to be something better than plywood.

"Gene Kearns" wrote in message
...
On Thu, 01 Jan 2004 19:37:05 GMT, "Lawrence James"
wrote:

The point of my link to the article was to support my statement that
polyester resin is not water proof. You won't find that I have suggested
that foam core is a good idea. I recognize that salt water can act as a
preservative. But what I see is that many boats are built with plywood.
In
the floor and transom. Some even use encapsulated plywood for stringer
grids. Many will get wet from rain water, not sea water. Not all, but
plenty of them will evetually suffer rot in these areas. So I see
nothing
good about using plywood to build fiberglass boats.


Ok... I'll bite.... what is the panacea for boat building?

--



Grady-White Gulfstream, out of Southport, NC.

http://myworkshop.idleplay.net/cavern/
Homepage
http://www.southharbourvillage.com/directions.asp Where
Southport,NC is located.
http://www.southharbourvillage.com/autoupdater.htm Real Time Pictures
at My Marina
http://www.thebayguide.com/rec.boats Rec.boats
at Lee Yeaton's Bayguide

"stealth" wrote in message
...
With today's technology and available materials, why do boat builders
still
use wood in the construction of their boats? From a layman's point of
view,
it seems ludicrous to do so given that wood rots when exposed to water.


There are several reasons, and various arguments for and against them.

Consider the wood used in four different applications:

Structural: provides the basic strength of the hull, includes stringers,
ribs, beams, etc.

Fill: The interior of the deck, transom, sides, and bottom.

Backing: wood is commonly epoxied onto the back of the fiberglass so that
windows, deck plates, etc. can be fastened down with wood screws.

Appearance: usually teak, mahogany, etc. used in places it looks nice.


If it wasn't for the rotting issue, wood would be an ideal material. It is
flexible, relatively light weight and easy to work with. If you decide you
need to mount something at spot "A" you simply drill a hole there, apply
some sealer and mount your something with a wood screw.

The Flexibility of wood is a major issue for structural members. You can
take a boat with wood stringers and give it quite a beating without any
significant degradation. Replace those stringers with metal and you could
have all sorts of problems. Metal fatigue can lead to stress cracks and
complete failure. The fiberglass, which is flexible, may start to tear when
it is beat against the far less flexible beams.

For large areas, such as transoms, it is hard to beat the strength to weight
ratio of wood. Again, flexibility is a desired feature. You can't use a
material that might fracture.

There are boats being made that don't use any wood at all. Only time will
tell if they consistently provide more years of service or not.

Rod McInnis

Try KeyWestBoats Their motto is No Wood, No Rot


"stealth" wrote in message ...
With today's technology and available materials, why do boat builders still
use wood in the construction of their boats? From a layman's point of view,
it seems ludicrous to do so given that wood rots when exposed to water.


s

On Tue, 06 Jan 2004 06:14:34 +0000, Tom K wrote:

Try KeyWestBoats Their motto is No Wood, No Rot


"stealth" wrote in message ...
With today's technology and available materials, why do boat builders still
use wood in the construction of their boats? From a layman's point of view,
it seems ludicrous to do so given that wood rots when exposed to water.


Wood CAN rot when exposed to water, but there are lots of wooden boats
that are 40-50 years old still floating out there (a lot of Canada's West
Coast fishing fleet are wooden - mainly Yellow Cedar).

Also, when encapulated and used basically as "filler", it can last for
decades if done correctly.

So, as others have said, wood remains one of the best materials to
build boats with.

Lloyd Sumpter
"Far Cove" Catalina 36: 20 yrs old, no rot in the wooden stringers.

On 1/6/2004 1:36 PM, Lloyd Sumpter wrote:

Wood CAN rot when exposed to water, but there are lots of wooden boats
that are 40-50 years old still floating out there (a lot of Canada's West
Coast fishing fleet are wooden - mainly Yellow Cedar).


You could probably count the total number of months my dad's Chris-Craft
has been *out* of the water on two hands, and she'll be 62 this year.

'Course, they used *real* woods like Indian mahogany back then, none of
this low-grade processed crud...

--
~/Garth