Martin PBM Mariner Patrol Bomber

Mariner - An Advanced Flying Boat for WW II

Martin Mariner flying boat in flight. U.S. Government photo.

The Martin Mariner PBM flying boat was relatively unknown as compared to the Consolidated PBY Catalina and was built during a time of rivalry between the two companies. A somewhat later design than the PBY, the Martin 162 was in due course to demonstrate a marked superiority of performance, and although it served in smaller quantities than the PBY during World War II, it continued to give important service for many years after 1945.¹ It was designed to serve as a patrol bomber, however, once the United States entered WWII, it became apparent that the Mariner was well suited for the high priority rescue of downed pilots and aircrews in the water.

With a deep hull and a gull wing, the Mariner flying boat landed and took off in water, and was not available as an amphibian until after WW II. The Mariner had two Wright Cyclone engines and a maximum speed of about 200 miles per hour.

Mariner Armament

Armament varied by model with the most common arrangement as eight 50-caliber type M-2 machine guns - two located in each of the following: the nose (bow), deck (dorsal), and tail turrets, and one mounted at each of the two waist windows as well as 2,000 pounds of bombs or depth-charges. The Martin Mariner typically had a crew of nine.

In the Atlantic, Mariners were used mainly as patrol bombers, and were involved with sinking 10 German U-boats. In the Pacific, Mariners were used in a forward patrol capacity and for ocean rescue missions (Dumbo Missions).

Martin Mariners in the Pacific - Open Ocean Capabilities

In the Pacific, Martin Mariners were used for forward patrol and for rescue operations (Dumbo Missions), in addition to their bomber role. As a forward patrol, the Mariners were sent in early during amphibious assaults. In these two roles, the less known Martin Mariner was chosen because of its more advanced design, sturdier hull and advanced training pilot training in wave studies to facilitate open ocean landings. The PBY Catalina was eventually ordered not to do open ocean landings.

Forward Patrols

As part of a forward patrol, these flying boats were based entirely on seaplane tenders, and together they created floating bases near the attacking amphibious assault forces. Martin Mariners participated in all the major offensive campaigns in the Pacific. The sea tenders became the supply line and housing for the crews of the Mariners and patrol duties sent the Mariners out to their maximum range, in search of the Japanese Navy. It was a Mariner that spotted the Japanese Navy during the U.S. invasion of Saipan. Although numbers vary depending on the resource, in the Marianas Turkey Shoot which followed, there was a hugely disproportionate number of Japanese aircraft losses, in contrast to those of the Americans.

Rescue Missions and Transport

Well suited for open ocean rescue missions, the Mariner played a vital role in recovering downed pilots and crews during air raids against the Japanese home islands and the amphibious assaults on the Japanese defensive perimeter. In heroic open-sea landings Mariner Dumbos rescued hundreds of airmen and seamen.²

The Martin Mariner also was used for night missions and as a transport. As with Catalinas, black Martin Mariners (nightmares) were used for night time attacks and reconnaissance. In a transport role, the Mariner was used by the Naval Air Transport Service, linking Hawaii to the South Pacific and Australia.

Dumbo Missions

Dumbo patrols (open ocean rescue missions) were named after the Disney character, Dumbo the flying elephant, (the movie was released in that same time period). Dumbo patrols searched for downed airmen, and the patrols got their name from the appearance of four engine, land-based bombers, with large wooden life boats attached beneath the fuselage. The appearance of a big lifeboat under the bomber made the aircraft look very unwieldy - just like a flying elephant.

These four-engine bombers included the B-17, and also in Europe, the Landcaster. The aircraft flew in search of downed air crews in the water, and in some cases, even the crews from sunken freighters were rescued. When the survivors were spotted, the B-17 or Landcaster would fly in low and drop the large wooden life boats to the men in the water.

Once the name Dumbo mission became synonymous with ocean rescue missions, it continued to be used, even when missions were assigned to the flying boats. These aircraft did not carry large wooden lifeboats, but instead, landed near the survivors and retrieved them, or dropped inflatable life rafts if landing was impossible.

Dumbo missions were extremely important, not only from a humanitarian perspective, but also because pilots were highly effective combat troops who were very expensive to train.

The Martin Mariner's Years of Navy Service

PBM Mariner with RATO. U.S. Coast Guard photo.

The Martin Mariner continued to improve with several new versions (the PBM-1 and -3 were the most numerous versions used during WWII). It became the first flying boat to be fitted with RATO (rocket assistance take-off).

Tthe PBM Mariner remained little-known to the public as opposed to the PBY Catalina, which probably furthered the rivalry between Martin and Consolodated. However, the U.S. Navy greatly appreciated the Mariner's open-ocean capabilities, and it was the Mariner, not the Catalina which was chosen to serve the Navy after  World War II, with approximately 500 being used in the Korean war.

Notes:
¹ Swanborough and Bowers, United States Navy Aircraft since 1911. Annapolis, Md. : Naval Institute Press, 1990, p.355.
²Richard Alden Hoffman, The fighting flying boat : a history of the Martin PBM Mariner. Annapolis, Md. : Naval Institute Press, 2004. p. 66.
³ Bill Gunston, Combat Aircraft of World war II. London : Salamander Books Ltd., 1978, p. 245.