Posted by Dan on October 15, 2003 at 20:18:03:
In Reply to: fibergals strength posted by Jeff Johnson on October 15, 2003 at 12:47:10:
You need to look carefully when comparing prices. Many true composite power boat designs require heavy biaxial fiberglass fully covering the inside and the outside of the hull. This is in addition to the epoxy fillets and biaxial tape over all seams. Biaxial is stronger than standard fiberglass cloth, but requires more epoxy. In this situation, you will typically see that they require thinner plywood for hull panels (ex: 1/4" instead of 3/8"). The greater strength of the fiberglass laminations allows them to specify thinner plywood.
In a nutshell...
- The price difference you see is probably due to the extra $$ to purchase large quatities of biaxial cloth and additional epoxy.
- This may be offset a little bit by the cost of thinner plywood for the hull panels and fewer fasteners.
- What is stronger? I don't know. 1/4" marine ply laminated between two layers of biaxial? or 3/8" plywood laminated on one side with 6 oz fiberglass cloth and a simple epoxy coating on the other?
Which is better??? I don't know. Boat design is an exercise in compromise and preference. Either approach results in an excellent boat assuming the designers have done their job design a boat for homebuilders that is conservatively designed taking into account their preferred building method. I think Glen-L has a good reputation and has been around a long time. The other company (assuming www.bateau.com) has excellent designs, an experienced designer, and excellent support.
Dan