What is the difference between a bilge pump and a submersible sewage pump?

Submersible pumps, submersible pumps and bilge pumps perform a similar duty.
They sit liquid, suck it up and flush it over a drain line to a new location.
They are usually driven by an electric motor mounted directly to the pump.There Alternative designs with the motor mounted at the top of the tube and shaftpump at the bottom. Known as “shaft pumps”, the pump is driven by a long shaft.
A shaft runs through the center of the tube shaft from the motor to the pump