Shear Obsession

Posted by Dave Houser on Jul 14, 2005

The shear clamp bends to follow the cut curve of the top of the side panels. This bend is in the vertical direction when finally installed on the kayak. When the panels are installed (stitched) they bend horizontally, so the shear clamps end up bent in two directions and they even have a little twist in them as well. The real goal is to have the left and right shear clamps bend exactly the same so the top of the side panels bend symmetrically along their length. . Since the deck on CLC kayaks are trimmed after installation, it is the shear clamp bend that determines the position of the top of the side panels and the symmetry of the shearlines.

To assure both shears bend the same amount I rip both shear clamps from one piece of wood and orient the ends the same on the kayak but rotate one shear clamp piece 180 degrees along the long axis so the natural curve of the pieces are concave toward the center of the kayak. I also use a thickness planer to assure both pieces start with the same cross-sectional dimensions. I also make sure the same amount of the shear clamp laps onto the side panels when gluing them on by making a stick with a notched end to measure the amount the clamp falls off the side panel. All this is an attempt to have the same amount of shear clamp wood on both side panels at corresponding stations after the clamps are planed for the rolling bevel. With the same wood orientation, with the same grain, with the same cross-sections both shear clamps should bend the same curve. The option to assure symmetry is to lay out the edge of the deck panel and match the top of the side panel to the deck edge which is not practical with a cambered deck.

I like shear clamps to avoid having to crawl inside to tape the inside of the shear typical of faceted (and strip) decks.

So, now to answer your question. If the panels are tending to bend sideways asymmetrically, just before installing the deck pull a string line from bow to stern and measure the distances to the sides to confirm the shears are symmetrical. If they are not push the short side out with a stick from below the shear clamp to the opposite inside chine corner. Then glue the deck on and pull the sticks after the epoxy cures.

In Response to: shear clamp bend by flip on Jul 13, 2005


  • wow by LeeG on Jul 14, 2005