Hi, I'm the new proud owner of a a 1990 Catalina 34 with a shoal keel and lately I've been finding about a 1/2 inch of water per day in my bilge. At first I thought it was a leak in my fresh water tanks so I drained them. Then I have closed all valves connecting tank to pump, sinks, showers, and thru-hulls and still, an un-ordinary amount of water appears in my bilge. All thru-hulls and areas around remain to appear dry. Any ideas? Please help. Thank you!