glass fiber sections fo stringers

Hi
I am changing the stringers on my 78 SN do the members think it is possible
To use extruded glass fiber sections in stead of wood say 200x60x8mm scribed to
The bottom of the hull and webs added all bonded back to the hull as you would
With wood using epoxy and matting, The sections come in 6m lengths and
would be a one time fix. Cost is not too bad @ $230 per length.

Roger.

Rodger, The 8mm double vertical cross section of the rectangular tubing you are planning to use sounds strong but I feel you need to do some research. The bending moment of the section moduli is what I would be concerned about. Not knowing the exact construction or the cross section of the new fiberglass stringers that CC is using to use as a example, the extrusions are a difficult call. The other variable is although the hull without stringers is strong, it's hard to say how much support it relies on from the stringers. The fiberglass extrusions are typically made with a very short strand of glass. The compression strength is great but the tensile is low and certainly not even close to a wood stringer. If you decide to go this route, I would wrap up the sides of the extrusions with mat and epoxy you are using to bond them to the hull. This will certainly add strength to the bending moment. I'm inclined to agree with Eric and go with the wood again unless you get lots of help in the structural engineering area.

Hi every one
Thanks so much for all the feed back on Glass fiber for stringers, the section I thought of
is a Pultrusion so has a good strength, the problem is its only a C section and to fit the hull, would cut off one flange and as its only 8mm thick would need 2 per main stringer + webs, have looked at the Coosa board which looks great and e mailed to see if they have
a UK distributor as a solid beam of around 38mm would work I think, I have to say the old wood stringers are wet and black/rotting but still in one piece and would have run ok
for 1 or 2 years not bad for 30 years of UK weather.
For bonding it all back thinking of using the west systems of Epoxy Resin, have taken a
list off the site on what to use, but not sure if the resin is the same here as its called 105 in
the UK not 635 so mail west UK to see if I have the right type for Glass fiber or Wood.
Thanks again for all the help on the site which keeps all the old boats running ( some may be better now then when new)

Many thanks
Roger.