We have a lot of houseboats in amsterdam. The most are connected with electricity, water and sewage. Now with the cold winter sometimes the water in the water pipe freezes. Then the pipe can get broken. When it is inside the hull the water goes flowing again and when it is not stopped in time the boat sinks just by to much drinkwater. It is the second boat this week which must be saved.
Here you see how it is done. After getting the boat out of the water it is pumped empty and then back because there is no leak. Still it has to dry and the water pipe repaired and better isolated. But I must admit for amsterdam the temperature was extreme low and a lot of isolation was not prepared for it.