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Pro Vee Race Boat Plans
Page Three
Sheer Clamps, Beveling the Framework

Sheer Clamps

The sheer clamps are two layer laminations of 1/2" x 1 1/4" softwood at least thirteen feet long. The two layers are glued together at the time of installation.

When you are either installing or dry assembling the sheer clamps, always bend both of them together so that you do not put uneven strain on your boat's framework.

Start by clamping the sheer clamps to bulkheads three and four. Then bend both sheer clamps around to the stem, clamping to bulkheads two and one as you go -- and making sure proper spacing between the bulkheads is maintained.

Finally clamp to the stem.

Now go back to the stern and bend the sheer clamps up to the end of the transom.

Although the sheer clamps should be perfectly straight from bulkhead three to the transom, you will notice that the strain of bending the sheer clamps to the breasthook will cause a slight bulge between bulkheads three and four, and a slight hollow between bulkhead four and the transom.

When I built the Mini Vee, I corrected this by placing a thin shim (about 1/8" thick) under the sheer clamp at bulkhead four. On the Pro Vee I decided I liked the shape and left it as is. Do it whichever way you prefer.

Examined from this viewpoint, you will notice that the sheer clamps rise up from bulkhead four to the transom. In other words, when your boat is right-side-up the sheer line will dip down from bulkhead four, causing a slight hook in the aft corners of your boat.

When your boat leans into a turn, the corner of your transom will be pressed down against the water and this hook will serve to hold down your bow and prevent a wild, porpoising motion.

Install one sheer clamp at a time. But, as you bend the first one into place, bend the other into its place as well and tie it off to even out the strain on the framework.

When the epoxy is fully cured, trim off the excess.

You can now safely remove the second sheer clamp from your boat -- in preparation for installing it -- without causing any harm to the structure. With the first sheer clamp securely installed, the framework will stand up to the uneven strain.

Install the second sheer clamp same as the first

Trim it off.

Looking suspiciously like a boat.

Beveling

Now it's time to bevel the framework in preparation for the plywood planking. The Pro Vee, with its hollow sections, is trickier to bevel than some boats. You cannot simply lay a straight edge across to see how your are doing, but must use bendy battens or smallish pieces of thin plywood. Bevel at the the intersection with the bulkheads first, where it is easier to see the exact angle needed, then continue and blend in the stretches between bulkheads.

The glue blocks along the bottom edges of bulkheads one and two will need some beveling as well.

Remember, if you take away too much wood, you can glue some back on and have another go at it.

A view of the beveled stem, sheer clamps and breasthook.

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