Dumbo was the code name used by the United States Navy during the 1940s and 1950s to signify search and rescue missions, conducted in conjunction with military operations, by long-range aircraft flying over the ocean. The purpose of Dumbo missions was to rescue downed American aviators as well as seamen in distress. Dumbo aircraft were originally land-based heavy bomber aircraft converted to carry an airborne lifeboat to be dropped in the water near survivors. The name "Dumbo" came from Walt Disney's flying elephant, the main character of the animated film Dumbo, appearing in October 1941.
By extension, "Dumbo" became the unofficial nickname for any air-sea rescue aircraft, including flying boats that had less need to drop heavy lifeboats since the aircraft could land on the water and perform rescues directly. "Dumbo" was also an unofficial nickname for any variant of the PBY Catalina patrol bomber which operated in a wide variety of roles including anti-submarine warfare against German U-boats in the Battle of the Atlantic.
After the 1950s with development and greatly increased use of helicopters for air-sea rescue operations, the Dumbo aircraft were retired and the term was no longer used.
History
Air-sea rescue by flying boat or floatplane was a method used by various nations before World War II to pick up aviators or sailors who were struggling in the water. Training and weather accidents could require an aircrew to be pulled from the water, and seaplanes were occasionally used for that purpose. A limitation of flying boats and floatplanes was that if the water's surface were too rough, the aircraft would not be able to land; in those instances the most that could be done was to drop emergency supplies to the survivors.
The first air-dropped lifeboat was British, a wooden canoe-shaped model designed in 1943 by Uffa Fox to be dropped by Avro Lancaster heavy bombers for the rescue of aircrew downed in the Channel. The lifeboat's descent to the water was slowed by parachutes. In the United States, Andrew Higgins evaluated the Fox boat and found it too weak to survive mishap in emergency operations. In November 1943, Higgins assigned engineers from his company to make a sturdier version that would right itself if it landed upside down. Higgins Industries, known for making landing craft (LCVPs) and PT boats, produced a 1½-ton (1400 kg), airborne lifeboat with two engines and waterproof internal compartments so that it would not sink if swamped or overturned. Intended to be dropped by modified Boeing B-17 Flying Fortress bombers, it was ready for production in early 1944.
After wartime experiences suggested improvements, Consolidated PBY Catalina aircraft were given extra features to augment their air-sea rescue capability. One such invention was a small platform that could be braced against the side of the flying boat's hull to allow a team of two Catalina crewmen to lean out into the water and rescue a swimmer.
Operations
Dumbo aircraft were sent aloft to patrol likely areas where American airmen might ditch. The Dumbo would radio the position of any survivors spotted in the water, and one or more actions could take place. The Dumbo, if a flying boat configuration, could land and pick up the survivors, or it could drop emergency supplies such as a lifeboat, by parachute. A nearby ship or submarine could be requested to come rescue the survivors, or an air-sea rescue station could be signaled to send a rescue boat.
Air-droppable lifeboats included the EDO A-3 lifeboat with an inboard motor, fuel, water and food; or a Higgins airborne A-1 lifeboat; both required parachutes to slow their descent. As well, inflatable life rafts could be dropped without a parachute.
In the face of vigorous enemy opposition, Dumbo missions sometimes required friendly units such as fighter aircraft to suppress enemy fire during the rescue attempt. In other cases, the mere presence of an armed Dumbo aircraft was enough to keep weaker enemy forces from engaging.
World War II
From the start of hostilities in World War II, air-sea rescues by flying boats were not unknown, though they were incidental to the aircraft's stated mission. In the Pacific Ocean theater, the first purposely assigned rescue aircraft, a PBY Catalina, was given the mission of plucking downed airmen from the ocean. From January to August 1943, such rescue flights based at Guadalcanal saved 161 aviators.