Yeah Minnesail, you do need to fix that. I'd do that as a seachest. For my part, I'd never drill more holes in the boat than I absolutely have to.
There is a fiberglass product I know as 'strong-back' which I believe is 'structural fiberglass' at McMaster-Carr (mcmaster.com) you can get that and fabricate a backing plate for yourself. You may be able to buy something like you want at McMaster, whether or not fiberglassI couldn't find any place that sells them. I thought I could save a step and save having to buy a big hole saw if I could buy a pre-shaped backing plate, but although they're in the catalog I couldn't find any website selling them.