Which small hatch

[DJS]

I want to fit a 6 inch round hatch it will not be walked on however, I would like it to be watertight; any recommendations?

Cheers

[ShinyShoe]

I've used ones like these (I usually use 4") on sailign dinghies for years and they are tough as old boots:

Barton screw fit inspection hatch sailing dinghy boat 155mm white or black | eBay

My latest sailing dinghy has one of these:
Allen Dinghy Inspection Hatch 145mm Total Diameter - Grey | eBay

Seems fine in the waterproofing front too.. Capsized a couple of times and always been fine. If I'm out in a serious blow I ship bucket loads of water over the bow and have two of these on a vertical surface that would be wet but not submerged. Always dry inside...

[Boatnomad]

Fitted one of these and it worked out well.

DECK ACCESS HATCH CLEAR 4" 100mm BOAT RIB YACHT DIY | eBay