A couple of months ago, I visited my R-27 that has been in the water all winter at a dock equipped with a de-icer. As I boarded, I could hear a small motor running. I found it to be the lower bilge pump, which was running constantly but discharging no water from a bilge that had more water in it than I usually see. The check valve was keeping the discharge hose full of water which froze in our spell of temperatures in the teens, blocking the hose and rendering the pump useless. I pulled the fuse, hoping the upper pump would do better as needed. A few days of warmer weather and the problem disappeared. The check valve comes out before next winter. So, where did all the water come from? All the cockpit drain gutters were full of ice and overflowed into the bilge. Daffodils are in bloom, so this issue moves to the back burner for now.