1st post and new to Catalina's and sailing in general. My wife and I purchased a 1979 Catalina 22 last summer. After test sail the boat was dry and in mostly good condition (we made minor replacements and upgradeds). The previous owner kept boat on trailer. We put in the water in September 2018 and have kept in slip without issue. Approximately 3 weeks ago (mid January) the boat began to fill with water in the cabin & Bilge (up to keel well). We have had quite a bit of rain so I pumped out. Went and checked on boat 10 days later and the water was back to approximately the same level. I put the boat on trailer an pulled out of the water. I let the boat sit and looked for water draining and could not find anything. Are there any typical issues I should check for other than the thing i have run to ground below.