Wooden Boat People

By McKenzieDriftBoat.com

Stitch and Glue questions

Ok, from what I can surmise with the stitch and glue technique you just cut the sides, cut the bottom, "stitch them together" then ??? what, epoxy the inside corners, take the stitching off then do outside? This next step is a mystery and I can't find a build-along that shows it?

My first boat is framed (wish I would have stitched it).

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Permalink Reply by Scott Hepler on July 8, 2010 at 11:59am

Another consideration is when the fiberglass is applied to the hull. In the case of the MBB designs, the fiberglass is applied to the sides and bottom (inside and out to prebend the shape of the bottom) before the boat is stitched. This puts the fiberglass into tension when the sides are bent during stitching and increases the rigidity of the panels. Most framed boats and wood strip designs apply the fiberglass to the boat after the sides and bottoms are attached to the ribs which helps protect the wood but adds little or no structural elements. There is no doubt that adding interior compartments add strength and rigidity to the boat, it is like the interior of an egg carton.

scott

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Permalink Reply by Chris Patterson on July 8, 2010 at 12:54pm

Scott,

I should try prefiberglassing the panels on my second boat. Glassing a flat piece of plywood has to be easier that glassing a curved hull!

Any concern about epoxy's 24 hour "chemical bond" window? Or do you try to cut out the panels and get everything stitched and glued in one marathon session?

Thanks for the information.
Chris

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Permalink Reply by Scott Hepler on July 8, 2010 at 1:15pm

The sides are scarfed, then glassed and then flow coated and allowed to fully cure before stitching them to the bottom. This allows you to sand and smooth the sides perfectly, both inside and out. MBB designs just glasses the outside of the side panels and both sides of the bottom. It is much easier and therefore faster, to make the sides flat and very smooth while they are flat. Since the sides are sanded and the bottom is sanded while rounding the chine etc etc you would produce a mecanical bond, and the combination of the structural fillet, and the biaxal fiberglass inside and out, you get a "permanent" very strong joint.
Just as a side note; the newer designs are using plascore for the bottom, and the outside of the bottom has a layer of Kevlar and then a layer of fiberglass. The bottom is then flipped over and pre-bent to the desired shape you want depending on how you want the boat to preform. More rocker for faster larger water, less rocker for less draft and better tracking, or some combination. Then a layer of kevlar and fiberglass is applied on the inside of the bottom. Once the epoxy has cured the bottom doesn't flex at all. This was the most scary part of my build because I suddenly realized that this is the shape of the bottom. And I wasn't going to be able to adjust it during the stitching.

scott