Small crack in hull

Hello all, I purchased a used Outback, I believe its somewhere between the 03-05 models and I noticed a small crack underneath the hull where the sail mast hole is located. I believe its the pressure from the sail mast being dropped into the hole and being bungee down over time. The previous owner mentioned he only used the outback for sailing most of the time. My question to you is how should I go about repairing this? I am not sure if the crack is leaking into the hull or just into the mast hole but just to be safe I rather patch it up. I do take the Outback 2-3 miles out into the ocean for 4-5 hours for some yellowtail fishing on the weekends and I rather pedal back than swim back Thanks in advance.