you can do it with spring clamps   that said, a couple c clamps are also useful and so when i do coamings, i usually use both.

i always test fit before glueing and confirm that i can properly position pieces with the clamps i have on hand....if you can't, then at least you recognized the issues prior to messing it up with glue that is curing with the whole thing in the wrong position :)

h

Here's what I used on my WD12 build. Not only did I do the test fit the way Howard recommended, I also placed a sheet of polyethylene onto the boat so that when the epoxy cured, the coaming did not stick to the boat.

I was then able to remove the coaming and finish sanding and shaping it without having the hull get in the way. This also made glassing the deck a lot easier.

Then when everything else was done, I just glued the complete coaming onto the glassed, weave-filled and sanded hull.

It took 18 clamps, BTW. I bought them on sale at Home Depot for $1.00 each (though it was 10 years ago when I built the boat, so the price may have gone up). FWIW, you can never have too many spring clamps. Since then I've bought dozens more.

Have fun,

Laszlo

   I used what I had, in addition I made a bunch of C-clamps by cutting 4-in diameter PVC pipe into 2-inch long sections, then cutting through one side. I pried these apart and put on the combing, they worked well

   What type of kayak, how much bend is in the deck? I used 32 C clamps on my Chesapeake 16 coaming, the smallest was a 3 inch C clamp. It was my first kayak build and I found the coaming challenging. I kept addding clamps until glue stopped oozing out.  I believe spring clams would have left gaps. I just measured, my coaming is less thatn 1 1/4 inches thick. At its widest point it is 2.5 inches and most of it is narrower than that. 

A man can never have too many clamps.

.

I have a 4" c clamp holding a carpenter bee trap to the fascia of my shop. A 5" c-clamp held the new kayak floating dock to the piling slide over night while I looked for the right size drill.  I had a c- clamp that holds my truck bed rack in place while I connect it up.  I have a c-clamp that keeps a light over the work bench in the garage.  I have a c-clamp that keeps the dillon loader on the bench.  I bought most of these clamps in the 70s when I was building a Y Flyer sailboat.     To say they will only be used on the cockpit coaming seems a little short sighted.

   I took all of the advice above. I did a test fit with the spring clamps. I wasn’t tight enough. I broke down and bought 20 more c-clamps ($2.99 each at harbor freight). I could have used 10 more. When it’s done I’ll try to find creative uses for them :-) If nothing else when I build my next boat I’ll have plenty of clamps!

And now with a pic

I ended up using a combo of C-clamps and spring clamps. Not ideal but it works.