This is what I came up with rather than use a padlock for a galley hatch lock. My original plan was to use one lock in the center but when the center was snug the sides were loose fitting so I went with two locks. Trouble was when I ordered I had to order five and since I wasn’t thinking of this arrangement I did not ask for them to all to be set on the same key, sometime I’l place another order and fix this problem as these Locke can’t be disassembled and rekeyed. They are stainless though and have a water prof cover that slides closed when the key is removed. They swing into a slit in a block to lock. A lot of time was spent on making sure my drilled hole was correct. For now I have keys marked red and green for starboard and port.
I didn’t believe my single hasp latch was keeping my galley hatch secured tightly enough. I found these stainless steel Mizugiwa latches on amazon.com. Two more galley hasp blocks were necessary, but that was easy enough. And they will accept a small padlock.
Here’s where I found them: https://www.amazon.com/gp/product/B01LA9Q9RC/ref=oh_aui_detailpage_o08_s01?ie=UTF8&psc=1
Interesting ideas. I was thinking you could use the same mechanism as the doors and have bars that run off to either side and catch under the gutter. Then you would have a single handle in the middle, with a lock, that actuates the bars to clamp on either side. So basically just like the doors but horizontal rather than vertical articulation.