Watertight hatch construction

I have a 17’ dory and want to rebuild my deck hatch lids. Anyone have pictures I can see? My boat is 10 years old and my flush mount hatches leak so I want a new design for my canyon trip this summer. Thanks for the help

My decked boat is upside down under four feet of snow so no pics now. Make a raised lip with Trex plastic fascia or decking boards. Make the lids out of plywood or honecomb core, with Trex edges that fit over the raised lips in the deck. Glue foam to the inside of the lid with barge cement. Epoxy goo adheres well to plastic fascia board if you rough it up with sand paper first.

Stainless hinges on one side. Spring loaded pull down wire clasp latches on the other edge, that pull the lid down tight. Down tightly is the key. I had to use hard plastic shims under the hinges to fine tune it, so the clasps pulled down evenly all around. Do that and it is water tight.

The clasps I bought are springy stainless wire you adjust by twisting the clasp before snapping it down. Round flush latches are useless. You need a wrench to adjust them. They don't pull down tightly and they leak.

These are similar to what I bought. Not exactly the same but similar. You need quick easy adjustment, no matter what. What's tight today is loose tomorrow.

https://www.amazon.com/a16112200ux0606-Stainless-Holding-Capacity-Hardware/dp/B01MR2O2TF/ref=asc_df_B01MR2O2TF/?tag=hyprod-20&linkCode=df0&hvadid=241898984112&hvpos=1o5&hvnetw=g&hvrand=429605820243323623&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9021322&hvtargid=pla-535337366356&psc=1

Mount the latch above on the lid. Mount the matching clasp hook on the deck, on a slightly angled chunk of Trex that is glued to the deck. That way the latch pulls the lid down instead of sideways.

So I'm building the decking of my boat using plascore and have a few questions about building the hatches. Do you glass over the raised lip described above? Also when mounting latches do you epoxy strips of trex to the underside of the deck to get a strong bite with the hinge and latch screws or do you have a different technique?

I did not glass the raised lip. Putting Trex underneath is a clever idea. I gouged out the fiberglass with an ice pick and dribbled in hot resin. Then a day later marked screw holes with a punch. And drilled holes. Thus us a cell phone answer. So brief.

When I made watertight hatches for my sailboat I made them as tight as reasonable and still be able to hinge them open and closed. Then I opened the hatch, spread thickened epoxy all around the opening where the lid joins. I covered that with Saran Wrap. Then I smeared the rim of the lid with thickened epoxy and closed the lid onto the Saran Wrap. The next day I lifted it to reveal an exact seal. Then I routed the hatch opening all around to create a scupper all around the rim of the hatch opening.