The hinges I use came from an item I needed for the rear stern hinged door on my graupner Adolph Bermphol Lifeboat. I needed some hinges, that were lightweigth, but alos not going to rust away when submersed in water, so came across thes little cute things, belonging to the aero moddellers brigade. They use them for the wing and tail flaps, light in weight, 2 sections of the hinge are a quite flexi plastic, with a stainless steel pin locking the two halves together, so no chance of premature rusting [ i didnt say any rusting- as appreciate you will get a slight corosion on this st/steel pin].
they are pre drilled with all the holes you see in the pic, so adapt easily to any fitment, plus you can source larger hinges if these are too small for your purpose. price? cheap as chips mate, bought a pack of 10 for less than £3.00 inc postage.
Thats why i said ive just simply cut a slot in the 3 layers of plastic ive bonded together, these hinges will slip in to the slot, then its either glue them in or drill through and drop some plastic rod through and heat over the ends, like a rivet, so can be removed/replaced if ness later, by simply cutting the heads off the plastic rivets and the hinge slides back out again. then to attach to the stern, you could use some stainless steel bolts and nuts, rather than just risk to epoxy glue.