Soft spots in side of hull

Hi, I have a mid '80s Hobiecat 16 that is developing some soft spots in the sides of the hull... Not sure what the construction of that area of the boat is, so I don't know whether to label it as delamination or what. I've seen a lot of repairs to soft spots on the deck of boats with epoxy plugs/cores, and I'm just wondering if a similar thing would work for the sides of the hulls? My first instinct was that it would, but upon thinking further I figured the sidewall construction might be more thin, and the cores wouldn't actually do anything