Rotten core on forward deck, how would you fix it?

[Enyar]

**Note - not a SeaCraft but similar design and build construction**

My boat is a 1987 and someone poorly sealed a pie plate on the forward deck of my boat. Unfortunately this has lead to a good amount of rot that extends outward of the pie plate at least 6" in almost all directions. 6" is as far as I can reach with the tools I had without cutting into the deck.

The pie plate leads to a decent size storage area. I'm thinking about ordering (or making) this trapezoid hatch and installing it into the deck where this pie plate was. This would give me better access to that storage area and allow me to cut out more of the deck to hopefully get to solid wood.

https://www.gulfstreamcomposites.com..._trapezoid.htm

A full deck replacement is not in the cards at the moment so I think my options are as follows:

1. Core with 1/2" marine ply imbedded in epoxy.
2. Core with some sort of composite material that I am not yet familiar with
3. Pour with Seacast

Anything else I should consider? Any other tips for getting as much of the core out as possible and also being able to replace the core with something?