Rear Hatch Rib Direction *fixed, many thanks*

[webbaldo]

Hi just to follow up on this, I ended up going for 4 vertical 3/4 ply ribs and 2x1 bracing in between.

This worked fine and ive since had no springback after skinning with 1/8 ply. The ply had made it fairly rigid as well. This will be treated and then coated in Alu

Since this pic, ive added extra ribbing to the hinge end and fitted a section for the locking mechanism at the base.

[markhusbands]

"If you have only aluminum on the outside, and ply on the inside, it will always be pulling toward the body, conforming."

I don't think so. That ply will try to return to it's flat condition, inside or out, pushing or pulling your ribs, flattening your hatch. If you put plywood on both sides of your ribs, they'll work together to flatten your hatch.

Personally, I think I am going to use four 3/4 plywood ribs, and only skin the outside with 1/8 ply in the bend-parallel-to-grain position. That stuff doesn't put up much of a fight. And I'll probably cover a shallow race for wires .