You can also use thickened isocyanate glue (instant glue) for wood. That has the advantage that epoxy can still fill in the cracks later when you fibreglass.
If you are using bead and cove the same glue can be used to glue them together and when the whole structure comes together it supports itself.
You can place a ledge under the cockpit cutout on which the uprights can rest while the glue hardens. You then hold it up against the cutout with a small clamp that attaches to the edge.
You can also substitute a wooden piece for the fillet. Cut a long section from a strip with a triangular cross section and notch it in the back as you go around the sharper corners.
Hopefully clear.
JohnK

: I'm a new poster here, building my first kayak, the great auk. I'm moving
: along fairly well and ready to build the cockpit rim/coaming. I'm just not
: sure how: do I take 2" pieces of cove and bead material and work
: around the rim? How are they going to stay in place w/ a dab of anything
: when you're bonding it to a mere 1/4 material wich is as much end grain
: and anything? If you manage to get it in place, is is the slurry or fillet
: which really hold it to endure the glassing and additional rimming? A
: little help would be greatly appreciated!