I used neoprene P-channel, made by 3M. This stuff came in a 2-row zip strip, and you can use or both rows as you wish. I tore it in two, putting one row on the outside lip of the hatch cover, and the other on the inside edge of the hatch lip. This creates a labyrinth seal, and traps water on the lip that would otherwise drain into the boat. Haven't had it pull off anywhere yet, but it's only 2 months old. I'll post again later if it fails.