: Hi again,

: Building my first child and i'm noticing some hybrids use a shear
: clamp and others don't. I don't see any mention of one in my
: plans, but does anyone know if the Hybrid Night Heron uses a
: shear clamp? It seems a bit crazy to attempt to attach the hull
: and deck at such a small edge if you don't use a shear clamp,
: but it must work somehow. Thoughts?

When the deck is made of plywood the plywood panel is thin and very flexible. It bends to shape and can be held to the sides with screws driven through the plywood and into a wood strip which sits along the inside, top edge of the hull. it is called a sheer clamp, because you clamp to deck to it (with screws) to form the sheer line where deck and hull meet. Many people put glue on the sheer clamp and remove the clamping screws once that glue hardens. Fill the holes and then there is no steel to rust away and stain things.

Cedar strip boats often wrap the strips in a continuous manner around the building forms. They just don't put glue between the last strip of the deck and the first strip of the hull until after they have removed the building forms from the inside. The joint at that point is reinforced with a double layer of fiberglass cloth on the inside and outside.

Hybrid boats tend to have plywood hulls with fairly straight sides which meet the wood strip deck at an abrupt angle. This would seem to be a great place for a sheer clamp. If yo want to put one in, go ahead. there is nothing wrong with that idea. But, you can just use a fillet of resin thickened with chopped glass, or something similar, which is then covered with a strip of glass fabric. Basically the same technique as used in the stitch and glue construction of the hull. Since the first strips of the deck might be already glued to the hull, there is no need to stitch it on. The glass on both sides adds to the strength and bonding.

In order to make it easy to get the glass and resin all the way to the ends on the inside, some strip builders will tack the strip of dry glass fabric to the upper edge of the hull using a few widely spaced drops of super glue, or hot melt glue. The fabric strip seems to work like a soft-sided sheer clamp. Once the deck is in place it is just a matter of coating the area with resin (brush on a stick works fine) and letting the resin harden to hold the boat together.

Hope this helps

PGJ