"The UBI did say the water pump was in poor condition and the sea pump leaked."
Does this mean that the water circulation pump (the one mounted on the front of the block) is going, too? Some people call the raw water pump that, some call it the fresh water pump and some call it the sea water pump. You might want to get a clarification from him.
It's rare but I have heard about a few pump shafts coming apart. It all has to do with the history of the boat and sometimes, it's just a matter of what kind of water it was used in.