My old cockpit locker tops are 3/4" solid teak. The tops, 2 wide planks were carefully edge joined with spline joints. They would move - cup down - with a soaking(rain or hose). Then the sun would dry them out - cup down. What's the problem, Max?

The new ones are plywood but plywood warps a bit as well. The new lids are supported and held down with 2 hasps. Still, I'm not sure what movements the new wood will make, both seasonally and with the constant soaked - baked cycle this area will go through.

One thing that helps with woods constant movement is to divide it into smaller pieces. I specifically opted for this small decking size ( 1 1/2") for that reason. And the system of strips with rubber caulking between was designed by woods movement. It's a genius way to let that movement happen with the least amount of warping. But I wouldn't be surprised if the lids cupped up and down a bit with moisture? But less than the old ones, I expect.

But some of the deck margin boards(perimeter) are nearly 3" wide. Though they are locked in epoxy on one face, they are exposed to wild swings in moisture and temperature on the other side. I'm curious how that will hold up. There will be a constant struggle between the two faces of the wood.

Plus I hope I didn't make my lid clearances too small. My eye always goes to the hinge clearance on doors, cabinets, furniture, so I wanted these to look right.

We're still having a blast following yours and Linny's adventures, Max, what a trip!! I could sit at your knee for hours listening to both of you.