gunwall clamp in the duck

I decided to put a sheer clamp in my wood duck 12 hybrid, when I removed the deck and forms, cut the hatch and then noticed that the side walls moved back inward, about 3" in some areas, so im doing the clamp,and going to epoxy it to the clamp,should I nail it as well, or just let the epoxy do all the work, please let me know your thoughts, Im not a fan about, dookieing and taping the 2 togehter,I feel the clamp will add strength,and about 2.5 pounds, small sacrifice for strength... thanx in advance...  Ocean

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RE: gunwall clamp in the duck

I had the same thoughts, but John Harris convinced me to go with the taping and filleting of the deck to the hull. I followed the design and it works perfectly. But if you insist on using sheer clamps, use sheetrock screws as temporary fasteners. Use small square scraps of quarter-inch plywood with the screws to prevent them from marring the deck and hull, and wrap the plywood in package sealing tape to prevent any accidental bonding. When the epoxy cures, the screws will be completely unnecessary and you can remove them. Fill the holes with a mix of epoxy and wood flour.


RE: gunwall clamp in the duck

One other thought: you might consider using temporary spreaders, 3/4 by 3/4 wooden sticks, chamfered at the ends to accommodate the hull angle, and wrapped in package sealing tape to prevent unintentional bonding, to keep the hull to its design shape until the deck is tack-welded into position with epoxy. When epoxy cures, unscrew the spreaders and they will easily fall away, and then you can fillet and tape as per the design. I used this trick in 2 problem places in my WD-12, and it came out great.


RE: gunwall clamp in the duck


I was also really suspicious about attaching the deck on my WD12 without sheer clamps, but eventually went ahead and did it as specified in the instructions anyway. Not only did I not regret it, but I can see how using clamps would have messed up not only the shape of the boat, but my ability to use it.The sheer clamps would have seriously interfered with my feet on the footrests.

They would have also made the build take longer since doing the taping is much faster than shaping and installing sheer clamps. And they would have added weight.

The process is really much easier than it sounds and looks. Once I was finished I was really wondering why I was ever worried about it.

So as a former skeptic to a current skeptic, my thoughts are "Back away from the clamps and do it the way the manual says".

Heve faith in the designers,


RE: gunwall clamp in the duck

Thanx guys for the input, Ill have to make up my mind soon, I like the spreader idea, and tack welding is good, I guess it will be hard to get up by the bow area, but Ill do it with much tenacity, I just want to make sure the shape doesnt move while I am trying to weeld it...Ill let you know how it goes...thanx again          Ocean

RE: gunwall clamp in the duck

Hi guys,

I had this issue last year of the sheer springing back in, and ended up putting the forms back in, tacking the outside of the sheer with hot glue, removing the forms and taping the inside. Try looking for my post, sometime back in May of last year, because it was very detailed of what happened. I would think that the instructions should probably be revised a bit, since this is not an uncommon occurence.

Hope this helps,


RE: gunwall clamp in the duck

I had a similar situation when putting the deck on my WD12H.  After completing the deck and removing the forms, the hull "collapsed" a few inches at various places. 

I glued a few short 1/4 x 1/4 (or maybe 3/8 x 3/8) strips to the undeside of the deck about 1/4 inch from the outside edge.  When the deck was in place, it spread the hull to match the edge of the deck so I could tape the deck and hull together.  The strips were small enough that they did not interfere with the fillets and tape.

 For what it's worth...  Mike

RE: gunwall clamp in the duck

Thanx dudes for the advice, I went ahead a did the sheer clamp, it added about 2 pound in weight, I feel better about them not interfering with my feet and the fairness of the duck was not effected at all.I was able to put temp spanners under the clamps to align the walls with the deck with out incedent, I got a good bit of the sanding done, and the edging went great with the block plane, ill post more pics soon....thanx again    Ocean

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