Why?

the keyhole cockpit provided makes it easy to get in and out, even with slightly stiff knees.  I often paddle with one or the other knee up for variety and there is room for that.  If your legs are long you could also cut back on the part of the deck usually left sticking into the cockpit on either side to give more room for knee bracing as with longer legs you knees would go further under anyway.  This would probably give room to paddle with two knees free.

If you do not mind a bit of extra work, build as specified, then if you really do not like it you could cut off the coming, enlarge the hole and rebuild.  If you enlarge the hole you would have to cut new risers and coaming anyway so it realy would not be that much extra work.

Ed

I made mine smaller (shorter) by 1.5 inches.  Result of where my bulkhead and deck beam landed (although I'm not sure how it happened).

No issues, far as I can tell.

Larry

Ed, thanks for the info. I think I will wait till I complete the build before cutting the opening any bigger. I have just completed the hull assembly and about to glass the bottom. So I keep trying to think ahead of the build on best way to proceed. I am not sure how to add the foot bracing. My older kit only has one position for the foot brace. So I am not sure if I should buy the ajustable foot braces or mfg. my own. Does anyone have any suggestions for a C17?

http://www.clcboats.com/shop/products/boat-building-supplies-epoxy-fiberglass-plywood/boat-fasteners-hardware/internal-footbrace-mounting-kit.html

I installed these (many here do); easy to install and allows you to use two different style of adjustable braces (actually, anything you can drill to fit over these bolts).

Just make sure you use very thick epoxy to set the bolts before covering with cloth/glass.  Mine wasn't quite there and they slid a tad - I had to block them into place overnight to ensure my braces would still fit.

Good luck,

Larry

Footbraces only have to be adjustable if you're going to share the boat or plan to change shape in the future. Once you get the cockpit all finished and fitting properly, it's actually nicer if the adjustments are permanent.

And Larry's right, the internal mountings are nice. I've used them on a couple of boats now and they work great.

Laszlo

I have read a few postings where people basically used a padded out bulkhead as their footbrace.  Very solid if you are going to be in rough water.

 I like the adjustable ones (with internal mount) as I have often shared a kayak with a friend, or sometimes bare foot vs shoes.  Closer in rough water, more relaxed on a quiet day etc.  

Ed