So I'm looking for feedback from people with experience repairing rotten wood shown below. I was replacing rotted wood between the bilge and ski locker and uncovered the ski locker floor to find this. It seems like I can remove the wood and should find fiberglass? I guess just looking for opinions... I have to repair it somehow. Thanks

You don't need wood at the bottom of your locker. If your going to reinforce anything in there just make sure to use marine fiber. Its real thick and can be purchased at a fiberglass store. I went and gel coated my entire floor. Heres my floor build...
http://www.socaljetboats.com/projects/new-floor-install/