Interesting exchange.
I guess what all these catches are doing is basically part A inserts into part B, connects (either by a spring loaded latch or simply by friction)
to be opened the hatch simply needs to be pulled straight up. A side whack or bump won't do it.
(Is this correct so far? I haven't quite figured out how the Southco latches work. I did find a page with their price in Rupees.

One general problem is that they all seem designed to fit on the side of a cabinet perpendicular to the door (hatch)
Well enough. Prices vary quite a bit. One of the Rupee priced Southco's has a 40 Newton pull ( upside down this would be 4 kilograms against the acceleration of gravity 9.8 m/s/s or about ten pounds. Four catches 40 pounds. That's a good hold. (The only risk is some piece of heavy gear inside slamming against it.
I whipped up a possible design (see image) that should be easy to make, durable, secure and does away with all the parts designed to be attached to a cabinet.

I found this T-handle stretchy pull latching on Amazon
http://www.amazon.com/Southco-Inc-Non-Conductive-resistant-aligning/dp/B002I05T9M/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&coliid=ISCI1KP548FG1&colid=1SYAYP02TXH3N

It's UV protected and no metal (even stainless corrodes in a salt water environment. The only worries in freshwater Canada are bear bites, hypothermia and the corroded souls of the occasional angry tourist)

And because I should be doing something else...... This design should work. It's important to align all the pieces vertically, which could be accomplished by making a simple form (pipe or dowel rods in vertical holes in a form that hold the Buttons (male pieces) vertically while they glue to the hatch lid. Use a little Dookie Schmutz to attach them to the bottom of the hatch.
Then the receiving pieces (female) are slid on to the hatch buttons and to be glued into the hatch lip. Just be careful not to get epoxy between the buttons and the receivers.