20 Seacraft; need help with a couple things

[mjl]

Hi everyone, i been a huge seacraft fan & forum lurker for years. A while ago i picked up a 1999 20 seacraft and love the boat. The boat has a few issues, the most important being a few spots on the floor that are starting to get a little soft.
I've read about some injection products, but not really sure if thats the right thing to do here.

pic attached of the spots.

thanks for looking!
Mike