Job #9 - Cockpit locker lids - measurements/prep

If I put the details here I won't lose them...
So about 33mm, but add 8mm for the blank bit at the start of the ruler, and also add a couple of mil for the reverse coaming on the cockpit sides.. so I need a hinge where the first hole is either over 45mm (so the nut for the through bolt will sit over the lip), or less than 20mm (so the nut will sit in the gulley)... the hatch cover is 12mm and I don't think there's enough thickness to rely on screws rather than nut/bolt..
Looking at that line of dirt at the bottom - I'd say someone in the past has used gaffer tape as a hinge...
So about 33mm, but add 8mm for the blank bit at the start of the ruler, and also add a couple of mil for the reverse coaming on the cockpit sides.. so I need a hinge where the first hole is either over 45mm (so the nut for the through bolt will sit over the lip), or less than 20mm (so the nut will sit in the gulley)... the hatch cover is 12mm and I don't think there's enough thickness to rely on screws rather than nut/bolt..
Looking at that line of dirt at the bottom - I'd say someone in the past has used gaffer tape as a hinge...