"Leo" ) writes:
I am not sure in wood thickness for strip planking: considering
reinforcements, I'm oriented in 1/2'' to save weight but maybe 3/4'' could
be better?

people used to use the term "strip planking" to describe what you are
planning but now its used more widely for any very narrow planks, like the
thin planks used on canoes and kayaks, called "stripper" construction.

I owned a boat much like what you are describing, 3/4 x 3/4 "mahogany"
(probably luaun) strips, sheathed in fibreglass cloth and polyester resin,
21 ft long, moulded fibreglass deck and cabin. I bought it used. I didn't
trust my sailing ability enough to buy a new boat. I tried to estimate the
dispalcement from lookign at the waterline adn got about 1200 lb but
that's suspect. It had a flat steel plate centreboard weighing 75 lb. It
was not built to sail but to be used as a plug for a mould for a class of
fibreglass sailboats but the fibreglass prototype was too heavy and they
gave it up. too bad they did not do their calaclutions before wasting all
the time and money. the plug made a lovely light dispalcement sailboat and
of course the hull was faired to perfection.

This boat was a bit too lightly built and had stress lines in the hull
from bow sheer to the base of the mast support and the same to stern. It
leaked at the centerboard slot and that also might have been due to the
compressive forces on the mast not being routed properly. But then all
wooden centerboard boats leak, don't they? The mast pushed down and the
shrouds pulled up and it was too much for the light hull. I don't think it
altered the shape of the boat, and I don't know if it weakened the hull, but
the stress lines in the wooden hull were plain to see.

The choice of wood was fine. I can't claim any expertise but I do think
I'd favour the 3/4" strips and I'd check the routing of those compressive
forces the mast and shrouds transfer to the hull. The hull had been
bleached on the outside before the polyester resin was put on giving it a
light colour. The polyester bond was fine except where the water leaked at
the centreboard and the polyester was coming away. I had the loose
skin cut away, the slot sealed, and new polyester put on. The slot
actually stopped leaking for one whole season.

I had it in the early 1980's. It was my first sailboat. It was old and
cheap, mostly because nobody wanted a wooden boat. I knew nothing about
boatbuilding at the time. I had to replace one small piece of plank where
some Sunday sailor in a Laser II rammed his solid fibreglass bow into it.
(I was on starboard, he was on port, but I doubt he knew the difference
let alone the rules of the road.) I can't recall very well what I saw when
making that small repair, but I think the planks were edge nailed with no
adhesive or bedding between planks.

I liked the boat. I'd buy another strip planked boat.



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William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
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Ok for "stripper" construction :-)
Substance is the same.
We have not yet an acceptable italian translation ;-).

Centerboard slot and deck stepped mast are always risk areas, where loads
are very high.
That's true on every small sailboat, specially in homebuilding, whichever
material or technique You use.

As You know, Polyester has not high adhesive properties on wood.
In the the early 1980's there was a low knowledge of epoxies.
Now the risks of crash, leaking or delamination are a bit reduced

Ciao
Leo

"William R. Watt" wrote :

people used to use the term "strip planking" to describe what you are
planning but now its used more widely for any very narrow planks, like the
thin planks used on canoes and kayaks, called "stripper" construction.

I owned a boat much like what you are describing, 3/4 x 3/4 "mahogany"
(probably luaun) strips, sheathed in fibreglass cloth and polyester resin,
21 ft long, moulded fibreglass deck and cabin. I bought it used. I didn't
trust my sailing ability enough to buy a new boat. I tried to estimate the
dispalcement from lookign at the waterline adn got about 1200 lb but
that's suspect. It had a flat steel plate centreboard weighing 75 lb. It
was not built to sail but to be used as a plug for a mould for a class of
fibreglass sailboats but the fibreglass prototype was too heavy and they
gave it up. too bad they did not do their calaclutions before wasting all
the time and money. the plug made a lovely light dispalcement sailboat and
of course the hull was faired to perfection.

This boat was a bit too lightly built and had stress lines in the hull
from bow sheer to the base of the mast support and the same to stern. It
leaked at the centerboard slot and that also might have been due to the
compressive forces on the mast not being routed properly. But then all
wooden centerboard boats leak, don't they? The mast pushed down and the
shrouds pulled up and it was too much for the light hull. I don't think it
altered the shape of the boat, and I don't know if it weakened the hull,
but
the stress lines in the wooden hull were plain to see.

The choice of wood was fine. I can't claim any expertise but I do think
I'd favour the 3/4" strips and I'd check the routing of those compressive
forces the mast and shrouds transfer to the hull. The hull had been
bleached on the outside before the polyester resin was put on giving it a
light colour. The polyester bond was fine except where the water leaked at
the centreboard and the polyester was coming away. I had the loose
skin cut away, the slot sealed, and new polyester put on. The slot
actually stopped leaking for one whole season.

I had it in the early 1980's. It was my first sailboat. It was old and
cheap, mostly because nobody wanted a wooden boat. I knew nothing about
boatbuilding at the time. I had to replace one small piece of plank where
some Sunday sailor in a Laser II rammed his solid fibreglass bow into it.
(I was on starboard, he was on port, but I doubt he knew the difference
let alone the rules of the road.) I can't recall very well what I saw when
making that small repair, but I think the planks were edge nailed with no
adhesive or bedding between planks.

I liked the boat. I'd buy another strip planked boat.



--
--------------------------------------------------------------------------
----
William R Watt National Capital FreeNet Ottawa's free community
network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-freenet email must have "notspam" in subject or it's returned