Vent protectors
 

You may have to rotate and zoom but basically a picture frame that the vent would just fit in. Screws through vent then aluminum into hull. They did prevent fenders from breaking the vent.

Thanks. Did you miter the corners?

OEM:
13-5/8 x 5-1/8 outer dims
Made from 1 x 3/4 x 1/8 Al angle with 1" dimension protecting vent and 3/4 dim under vent lip with screw holes
One corner is mitered and welded then ground outer radius
3 corners have a notch cut out of 3/4 dim, bent to 90 on joint before holes drilled - I would have tacked the hull side of that joint but mine are not.
Attachment 25410

Attachment 25411

Awesome. Thx all ��

Looks like a perfect place to use those aluminum (brazing) welding rod and a propane torch to do the corners no strength issues to worry about. I’ve used them on a couple none structural projects that have held up well