Handy billy — also known as Handy-billie —is an emergency portable pump that for decades was commonly placed aboard most U.S. Navy ships from World War I on, as well as later use on civilian craft.
The handy billy, formally designated "P50", because it pumped 50 gallons per minute, was gasoline-powered and could be used, during flooding conditions, in conjunction with other pumps on the ship. However, it was especially valuable when the ship lost electrical power and normal pumping ability was lost.
On smaller ships, it was a critical piece of equipment.
The pump gained its name because it was very “handy” and dependable. It was especially handy because it could be easily transported from place to place by two strong crew members, one at each end, as it weighed 160 pounds during World War II.
The handy billy could be used for fire-fighting and/or pumping water from flooded spaces aboard ship.
See USS Auk (AM-38)