Anyone make Dry Storage Hatch Kits?

I got a tandem I want to make into the mothership of day trips and load down with gear. I don;t like dry bags. Anyone know of instructions/kits/whatever for either installing a dry hach…including even sealing the stern bulkhead. Noob.

Don’t like 'em?
Dry bags keep stuff dry. Even in dry hatches. Which, more often than not, aren’t completely dry.

Unless you just dropped $4000 on a composite tandem, you will never be able to get an absolutely dry hatch. Bulkheads in plastic boats leak. It’s the nature of the material.