And if you can get the old one out in 1 piece, use it for a pattern, unless you're wanting to do something different. Paint the new piece on both sides, and give it a couple days to dry before installing it.Clamp it in place & drill your holes using the existing holes in the hull as a guide.
Like DZ said, be sure & use SS hardware (reuse the old if it's SS) & seal it.
ST