Purpose of this hatch? And can I waterproof it?

[EngineNoO9]

This is on the top/front of the helm on my 2001 aqua patio pontoon boat. The side hatch for access is watertight but this has a giant hole that just lets water in?!? Can’t for the life of me figure out why it’s be like this but then trying to see if I can make it water tight. Can’t seem to find a latch to fit the smaller hole ~1”. I could drill it out I guess… and add a gasket on the inner lip.

 

[southkogs]

Can't quite tell, but I'm gonna' guess it's a cooler. If there's a small drain hole somewhere down on the bottom, my guess is that it drips water out the bottom of your deck.

 

[dingbat]

The only cover on my boat with a hole is the anchor locker. Rode is stored inside. Rode comes out hole on top during use

 

[EngineNoO9]

Can't quite tell, but I'm gonna' guess it's a cooler. If there's a small drain hole somewhere down on the bottom, my guess is that it drips water out the bottom of your deck.

The water bag for the sink is in there and a small cooler fits in there. I put the fire extinguisher in there too for quick access. I’ll check for a drain hole. I didn’t see one but didn’t look too closely.