Hello,
The keel trunk is a bit of a squeeze to get into and repair. Depending on where the damage is and how big it is you might want to consider getting to it from inside the V-birth area. I think in fact a good repair would have to be done from inside to outside.
Also did you know there is a false bilge inside under the deck? That said, you'll want to keep all the water out since it has no way to drain.
I drilled a large hole in the V birth floor next to the bulkhead and sucked all the water out with a vacuum, then let it dry for a few weeks. I then made repairs and used a lot of glass, resin and epoxy.