coaming

noun2

1. •
   On a boat, the vertical side of above-deck structures, such as the coach roof, hatch, and cockpit.
2. •
   A raised frame, designed to deflect or prevent entry of water, around an opening (e.g., a hatch or skylight) in a flat surface, such as a roof or deck.

   • Creepers threaded the wrecked windows of the coaches, ancient and chalky brown with their riveted seams and welted coamings like something proofed for descents into the sea. — 1979