: Trying the picture thing again, the first one was too tiny:-(

Suction cups might work if you wait for the varnish to cure completely and you get a nice glossy finsih for them to grip to. You'll need to cary sustion cups with you, so consider where you will store them--certainly not inside the hatches they are meant to open!

You know, you can weaken the effect of the magnets holding the hatches closed if you put another magnet near your hatch seals. Get the orientation of the second magnet correct and glue it to your suction cup with a flexible Goop. The combination of reduced magnetic pull and suction may make it a snap to pop open those hatches.

If you are going to carry extra devices for opening the hatches, why not just carry a wooden hatch key? Shape your hatches with a wide lip at one side, ans slip a crowbar-shaped piece of wood in there as a lever. Easily replaced with a quickly-whittled branch if you lose the original lever, and any marks they might make will be to the underside of that lip, so not visible when the hatch is attached.

PGJ