: thanks fellas,
: issues with ply noted, I have heaps of ply at my disposal hence the question,

You might as well dispose of the plywood on some other project. Or use it for hatches and cockpit coaming. This isn't the place for it.

: To elaborate on what i was thinking, i'm finishing off a boat I started
: years ago, a oneocean Cirrus hybrid. Being a hybrid it has relatively
: sharp angles at hull/deck join. aS well the cirrus has a very shapely bow
: for a S&G.

: i don't have ready access to WRC or paulownia but have lots of ply so my plan
: was to shape the upswept curve with a bandsaw (3/4 20mm wide) and run a
: heap of kerfs along the length of the clamp to allow it to conform to the
: entry exit angles without placing any load on the sides as I've already
: stripped the deck and glassed the hull. Not worried about strength just
: somewhere to plonk some glue. Good point about planing difficulty, might
: be a job for my trusty 4"disc sander

Don't work so hard. Don't make so much sawdust. Get on to the important work--putting on the strips. Keep reading.

: however, i do have some left over WRC strips that I could laminate together
: as another option.

That would be overkill. Don't do it. Keep reading.

: one idea often leads to another . . .

Some ideas can be trashed from the get go. I think using plywood for sheer clamps on a hybrid deck is a definite candidate for the trash can.

The purpose of a sheer clamp is to provide a strong foundation you can put screws into whenyou are bending a piece of plywood over the top of a kayak to create a deck. That plywood wants to stay flat. All the bends and curves build up tension as surely as stretching a rubber band. To hold the plywood in place those screws need something to grip. If you went with plywood and small screws, you would want to orient your ply so that the laminations were horizontal, and glued to the hull. The face of the plywood would then be the mating surface to the underside of the deck. Even if you plane or sand through the face veneer of the plywood this will still give the strongest grip to the deck screws.

BUT you are NOT using a PLYWOOD deck ! You are creating a hybrid boat with a deck made from strips. You don't need sheer clamps at all. Your outer strip will be glued to the top edge of the hull panel. Run a handplane along that, and with a few gentle passes you will get a nice edge to glue to. Heck, you could smooth thinge with a sanding block. If your hull is made from 4 mm plywood, then your glue line will be 4 mm wide--which is just about the same as the bond width on 3/16" strips edge glued to each other.

If you really think that edge strip on the deck needs more support where it joins the hull, you can rips some very small pieces from scrap strips and glue them inside the hull. You are not driving screws or popping staples or nails into these. They are just to give a bigger surface area for your glue. So these strips are VERY small. If you have 1/4 inch strips set your saw to a 45 degree angle and rip off some pieces which are triangular with 2 faces that are roughly 1/4" at right angles to each other, and a slightly longer hypotenuse. Anything over a foot long will work. Butt them together to cover the length of the boat. Use light clamps to hold these in place until the glue hardens. Cheap wire paper clips will work for this. Sand or plane off any high spots.

Glue on the outer strips for the deck, letting them run straight. Once the glue hardens you can use a saw to cut the overhang close to the hull, and then plane or sand to get a smooth edge.

The added gluing surface gives you a gluing "face" that is about 10 mm or 3/8' wide. It is a bit more than half the width of one of your deck strips, so there is going to be plenty of support for the strips.

These very small "mini sheer clamps" take the place of a fillet of thickened resin in that joint area. That saves you from climbing inside to put in the fillet. Since you'll cover the inside of the deck with glass, leave enough hanging over to go up the side of the hull about 2to 3 inches. Exact measurements aren't important here. Nobody sees the edge. It will go over the triangular woodstrip "clamp" with no problem. No added glass tape is really needed unless you feel the need for additional stiffening or reinforcement. Personally, I'd put any extra on the OUTSIDE of the joint. Getting tape into the tight areas in the bow of a kayak is no fun, so you may not want to even try.

Hope this helps.

PGJ