It's not unusual at all to have to plane into the hull a bit. And you're right about the area (cockpit) that will get the most planed off. Have fun!

George K

On my Chesapeake LT's, I wanted to preserve the top outside edges of the sheer planks as a reference for the hull to deck joint. They are already matching eye-sweet fair curves, so I didn't want to plane into them. The result was that there were some small gaps between deck and the sheer clamps on the inside of the cockpit. Squeeze-out from gluing on the decks partially filled them, but I ran tiny fillets between the underside of the deck and the sheer clamps wherever I could reach anyway, to seal the boat well against water. I would do the same again.

Old Yeller 

On my SW Sport Hybrid, the instructions called for the clamps to stand proud further where the curves were steepest. In a couple of areas I didn't have them quite high enough, but left a slight gap on the inside rather than cut too far into the side panels. The gap filled easily with squeezed out epoxy when fitting the deck.

Planimg into the side panels is not a good idea. Keep in mind that the bulkheads amd deck beams could end up too high, resulting in humps, bumps, and a wider gap in the hull to deck joint. I would rather have a small void on the high side of the sheer clamp. You could identify any low areas using the planing guides and mix the epoxy/cabosil a bit stiffer. You will be able to lay a thicker layer on the sheer and fill the void. Dont skip a dry run, it is time well spent! If you are using straps to bemd the deck, be sure they are over the deck beam amd bulk heads. Tightening the straps too much will not close the gap at the sheer!!

                                  Good luck!!

I am not an expert but I am currently planing the shear clamps on my second Chesapeake.  I suggest that you re-read para 3 on page 105 of your manual.  "You will need to plane INTO the plywood panels along the center section, with the greatest depth at the deckbeam.  From the deckbeam forward and aft, this bevel will roll back to level with the top edge of the plywood panel."  

I followed the directions explicitly on my first build and it came out great with no gap at the deck.  I am doing the same on the second.

Yes, I was aware that the manual suggests planing into the sheer panels. I chose to ignore that, because I wanted to preserve the sweet sheer line already designed into the top edge of the sheer panels. Once you start planing into the panels, to re-establish a fair sheer line you need to do a lot of additional careful planing, which I saw no reason to do.

Excellent results can be obtained either way. I chose the easier way, with zero compromise in build quality.

Old Yeller

I would also add that it's possible to plane so much off the sheer clamps that the sharp points of the ring shank nails can poke right through the bottoms of the sheer clamps and into the inside of the boat. It's smart to check your sheer clamps for enough depth before you start installing the deck. I shortened some of my nails slightly by clipping a bit off of their tips.

Old Yeller  

Ah, thanks Mark N, although I'm working from an ooooold instruction manual (roughly about ten years old), and it never mentions planing into the sheer clamps.

I did the stern yesterday and will do the bow today, so far the amount of planing into the sheer clamps is pretty minimal, but good to know that at least according to the (latest) instructions it's not the unusual!