PLEASE READ THIS... REGARDLESS OF YOUR BOAT TYPE.... THE ISSUE IS RELATED TO HOW YOUR COCKPIT DRAINS ARE DESIGNED....... THIS COULD MEAN MOST CATALINAS, HUNTERS, AND WHO KNOWS HOW MANY OTHER BOATS! Most Catalina 27's that I have ever seen have the same kind of drains that ours has.... two simple "nipples" that are connected to two 1.5" diamiter hoses which are bent in an "S" shape and drain out two thruhulls....that are below the waterline, and have no seacocks. Normally, these hoses are very hard to reach and inspect. The bottom of the hoses rot and develop holes and slow leaks. In our case, when the boat was tied at the dock....the lower side of the hoses was above the waterline. When a number of us were in the cockpit.... we submerged the stern enough that water filled the horizontal section of the hose.... and it started leaking slowly. As with any leak, the deeper below the waterline... the faster the flow..... so when we were heeled over during sailing... these hoses leaked pretty quickly........ but because of where they are it is nearly impossible to check them while underway and when they are leeking the most. Also, when heeled the "drain path" from the leek to the bilge will shift away from the centerline... so quite a bit of water can run past you while you look at the centerline, thinking that it is the prop shaft leaking! (Please note.... when I replaced these hoses.... the top sides looked and felt like new... but there was a "soft" line along the horizontal "bottom" of each of the hoses where water had sat inside over the years. Even if they look good..... check them VERY closely or better yet... replace them with new heavy duty hose!) It is VERY FORTUNATE that we got this located and fixed this past fall....... We have already had several heavy snows this winter..... and the weight of the snow would hav submerged the stern just enough TO SINK THE BOAT AT THE DOCK!!!!