Mick, I'm not familiar with NuLoc devices, and I've just spent a good hour plowing through the catalogs. Next, the Internet. You're hitting on the general idea...something that is integral to the hatch or yak, light, strong, and fail-safe. Back to the idea before on SS studs in the hatch lip...not bad, and one could use O-rings inset into the knob. Then again, the idea of SS allen head sounds better. Especially flush fitting, perhaps against a thin bronze/ss/carbon glass liner? Trouble is, who makes SS allen bolts? Okay, how about this: hatch with lip to catch on one side, a hold down on the other, whether internal (a la Ross) or external, like a knob, bolt, etc. The reason for a tight seal is that I tend to do dumb things like surf big sets, shooting tubes, catch a little air off the waves shoulder, and...from time to time, really eat it big time, like in blood, guts and feathers all over the place. Fortunately I'm a bonehead, so little damage is done aside from the dents in the sea bottom... ;)

NuLoc?? Hmmm...anybody else have an idea?

muy grande regards

tig (aka The Denter of Sea Bottoms)