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Sunday, October 02, 2005

Composite replacement for Plywood

So a number of things have progressed over the past few weeks... CAD: Local owners of a W42 'Nightingale', who were in possession of original blue line drawings, loaned them to us while at the WestSail rendezvous last September. I had a company in Seattle scan them in. This has given us more accurate dimensions than the ones I had to "guesstimate" from the construction manual drawings. As a result, I pretty much had to start the CAD drawings all over again. No big deal as we wanted to make a few changes after seeing Nightingale. MATERIALS: My wife encountered the president of Coosa Composites at the boatyard as he was making the rounds in the PNW showing off their fiberglass/foam composite "replacement" for plywood. This stuff is pretty cool. We ordered a 3/4" inch sheet of their "Bluewater 20" from Fisheries Supply in Seattle, to see what it was like. Well, this weekend I cut off a section from the 8x4 foot sheet and did a few test laminations. This stuff is very stiff and strong. Superior laminate adhesion than plain plywood. And the specs exceed that of plywood for strength. It cuts VERY easily (a circular saw goes through it like butter), much lighter than plywood (about 40% lighter). And IT DOES NOT ROT. (and water retention is very low < 1%) So, it looks like we will be using this stuff for floor timbers and bulkheads using traditional hand layup for tabbing. This will be much faster than the previous plan of glass over foam (whether vacuum infused or not). The downside is that it is pricey. This one sheet was about $180, and that was at builder's pricing. Other things ongoing: I still need to get some stainless parts drawnup and to the fabricator. Next weekend will see the transferring of dimensions from the inside of the hull for bulkhead templates. Thats all for now.