I was thinking of extending those 'grooves', all the way to where they drop off, over the side - no way for water to pool in the ring. If done well, would actually be a feature, in appearance.

The crown of the deck will determine how long these drains need to be.

It may not appear to be so in the photos but the drains at the side of my hatches (which started out as finger holds) are at the lowest point on the sides of the hatch and on the same level as the lowest part of the deck lip. So they drain any water in the gap between the hatch cover edge and deck.

The raised bead in the design is considerably higher than the drain at the sides of the hatch and the wide deck lip, housing the magnets, makes it harder for water to climb up to gain entry to the bead/gasket seal.

I say the side drains started as finger holds but the magnets are so strong it takes considerable muscle, and the loop on the cover, to remove the hatch cover so they are useless to use with fingers to try and open the hatch cover.

I've had a few people say they like the look of the three drains on each side of my hatches.

Rob