Will this be strong enough support?

Here's my front deck.


The hole with the two coolers sitting in it is 53" long x 13" wide. I want to take a piece of 3/4" plywood and put it over the hole with some piano hinge so it opens like a hatch. If I put a 2x4 running lengthwise in the middle of the board, will that stiffen it up enough to walk on it or would I bet off running a 1.5" piece of angle across the middle and split the plywood into two separate hatches? Eventually I am going to redo the deck extension in aluminum to make it even better but this is a temporary solution.

I'm just trying to copy what I see boat builders do to reinforace hatch lids. Here's an example.

Tough to say actually.. but chances are it would be on the flimsy side. You're probably best off splitting the hatch if you don't have anything too long that needs to fit in there.