Attaching sheer clamps to Chesapeake Double without assistant

I'm building a Chesapeake Double, and I need to attach the sheer clamps without any help. Has anyone done this successfully?

My initial idea is to do them one side at a time, by driving pins into the side 3/4" from the sheer at each station to locate the sheer clamp properly, and progressively clamping it in place. Then, after the first side cures overnight, flipping the panels over and doing the same on the other side with the panels together to match the first side.


Any thoughts?


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RE: Attaching sheer clamps to Chesapeake Double without assistant

i have built a number of the chesapeakes without an assistant.  for sheer clamp attachment, i just use spring clamps to hold the sheer clamp to the hull side for pre-fitting/marking and when i was glueing them.... and it was pretty straight forward.

from a process perspective, i test fit the sheer clamp to the hull and then used a pencil to lightly mark a line on the inside of the hull where the sheer clamp will be positioned when i finally glue it.  the mark also identifies where i need to put my epoxy glue that is gluing the sheer clamp to the hull.  

i did this whole process on a flat floor covered with a sheet of plastic.  

i then took the clamps off and put the sheer clamp on the floor adjacent to hull.   i then mixed up my epoxy/cabosil and applied it to the hull using the scribed line to show me where the epoxy needed to be.   i then started at one end re-attaching the sheer clamp to the hull with the spring clamps using the pencil mark to tell me exactly where the sheer clamp needed to be positioned.  (i had enought spring clamps to do one every 6 to 8 inches).  when i was done clamping, i cleaned up the epoxysqueeze out. it was pretty easy...

after the first hull side/sheer clamp was complete, i repeated the process with the other side.

matching the sides should be easy.    but you will use your pencil-marked line to know where that is.  in my view, you don't need pins.....spring clamps can do the job just fine.

anyway....that's my 2 cents on this

best of luck.





RE: Attaching sheer clamps to Chesapeake Double without assistant

   It really is best to clamp both at the same time, to the backs of the side panels while they are positioned face to face. Clamping a single layer of ply to the clamp would require clamps every 3-4 inches since the ply is so thin; but as the "meat" in a clamp sandwich, the clamp's stiffness prevails and ensures a more-fair ply surface.

Mark a line on one hull side panel, support the two panels on a flat surface with the edge overhanging (long bench, floor with lots of 2x4 blocks to elevate it, whatever), then wet out the clamps with flock-thickened, slow epoxy, and position the clamps over and under the side panels. Line up the top one with the line, and simply sight from the upper to the lower to align its top edge. Work from the middle toward the ends, clamping every 8" or so (split ring pvc clamps are handy here).

If it bothers you, you can keep things a little cleaner by placing a block under each end of the upper clamp, to keep its gooey surface from rubbing on the panel until you get it aligned and clamped. The lower clamp will naturally droop away from the panel until it is clamped.

The clamps look lots better if you remember to round their lower inside corner with a 3/8 - 1/2" radius router bit first...

RE: Attaching sheer clamps to Chesapeake Double without assistant

 >>The clamps look lots better if you remember to round their lower inside corner with a 3/8 - 1/2" radius router bit first...

Not just look better, but less vulnerable to damage, lighter for the same strength and less likely to bruise legs. This should be a standard step in the manual.



RE: Attaching sheer clamps to Chesapeake Double without assistant

wanted to second/third the rounding of the lower inside corner.  very easy to do once they are glued onto the flat panel but before they are stitched up.   glued up to the panel they are nicely held down so you can get at it with a portable router.  i would also highly recommend the 1/2 round.  as laszlo points out, lighter, no difference in strength and more rounded....less likely to bruise.  i would have used a 3/4 round if i had it.

functionally, the shear strip is really there to create a glue interface to attach the deck to the hull for 'tortured' deck construction (i.e, bending a piece of wood against its will).

RE: Attaching sheer clamps to Chesapeake Double without assistant

   Thanks for the advice about rounding the edge. Good call, Nemochad. I'll take hspira's suggestion and do it after they're bonded to the hull sides.

The pins (or maybe concrete blocks) would not take the place of clamps. My plan is to make a mark during the dry fit on both the clamp and the hull side to line up during the actual bonding process. The pins would be near the ends to act as the set of hands a helper would otherwise be providing. I can be in the middle, holding the wetted clamp up and moving it so the ends are over the right locations, then lower it and push it in at the center until it aligns with the line I made 3/4" from the edge, and the two alignment marks I made during the dry fit line up to get the longitudinal alignment. The ends would be pressing against the pins. I'll then use spring clamps as described, working from the middle outward. If I use pins, I'll wax them to prevent them from bonding to the boat permanently.

These clamps are more than 20' long, and handling one of them alone is quite a challenge. Trying to do both, I think, would be more hassle than the time saving is worth. It would be an extra day. I'll try it dry, though. Maybe it will work. 

The side panels are still clamped together from cuttng, and will remain that way until both the clamps are bonded on and they're ready for stitching at the ends. I slipped packing tape between them to make sure they don't stick together when the clamps are bonded on.

Thanks for all the help! Forums like this are a great tool for sharing information.


RE: Attaching sheer clamps to Chesapeake Double without assistant

   Even if you glue one at a time, use the second one as a caul on the bottom. You can just tape it in place. The clamps are (in addition to hspira's note) to cause the "live" hull edge to be a fair curve. The ply will be lumpy/wavy if you place pressure at isolated spots, only, on the thin ply.

For 3/4" thick clamps, I doubt a 1/2" radius bit will work on a glued up clamp- the bearing is too tall. I rout mine first. And, I'd recommend running the clamps long and mitering them at the bow/stern. You'll get a good deck gluing surface, and won't need an end pour.

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