Reading level:

Martin PBM Mariner

Glenn L. Martin · Maritime Patrol · USA · WWII (1939–1945)

Martin PBM Mariner — Maritime Patrol
Open in interactive gallery →

The Martin PBM Mariner was the U.S. Navy's principal twin-engine maritime patrol flying boat of WWII. Martin built 1,366 PBMs between 1940 and April 1949. The Mariner served as a long-range anti-submarine patrol aircraft over the Atlantic, Caribbean, and Pacific, and continued in U.S. Navy service through the Korean War. The aircraft sank or damaged about 14 German U-boats during the Battle of the Atlantic and supported amphibious operations across the Pacific from Guadalcanal through Okinawa.

The PBM was a twin-engine high-wing flying boat with a gull wing and twin tail fins. Power: two Wright R-2600 Twin Cyclone 14-cylinder radials (1,700-1,900 hp each). Maximum speed 211 mph; range 2,700 miles; service ceiling 19,800 ft. Payload: 8,000 lb of bombs, depth charges, or torpedoes in two underwing bomb bays. Defensive armament: typically 8 .50-cal Browning machine guns in nose, dorsal, waist, and tail turrets. The aircraft used a single hull plus two stabilising floats under the wings; some PBM-3 variants had retractable landing gear allowing operations from both water and conventional runways (an unusual amphibian configuration).

Combat use was concentrated in maritime patrol and anti-submarine roles. Atlantic-theatre PBMs flew anti-U-boat patrols from Bermuda, Iceland, the Azores, and Brazil 1942-1945. Pacific-theatre PBMs supported every major amphibious landing from Guadalcanal (1942) through Okinawa (1945). The aircraft also flew rescue missions for downed aviators — a PBM-5 picked up survivors from USS Indianapolis after that ship's 30 July 1945 sinking. Royal Australian Air Force PBMs supported Pacific operations from 1944 onward.

Post-war the PBM continued in U.S. Navy service through the Korean War as VP squadron maritime patrol aircraft. Final U.S. Navy retirement was 1956. The successor type was the larger Martin P5M Marlin (more powerful engines, redesigned hull). About 5 PBM airframes survive in 2026, including the airframe at the Glenn L. Martin Maryland Aviation Museum (Middle River, Maryland — Martin's original plant). No PBM is currently airworthy.

For Kids — a shorter, friendlier version

The Martin PBM Mariner was a big flying boat used by the American Navy in World War II. It had two engines and could take off and land on water. It flew long patrols over the Atlantic, Caribbean, and Pacific oceans.

The Mariner was bigger than most planes of its time. Its wings were shaped like a gull, and it had two tail fins. Two powerful engines gave it a top speed of 211 miles per hour. It could fly as far as 2,700 miles without stopping.

The plane carried bombs, depth charges, and torpedoes to hunt enemy submarines. It also had eight machine guns to defend itself. During the war, Mariners helped sink or damage about 14 German submarines in the Atlantic Ocean.

Some Mariners could even land on regular runways, not just water. This made them very useful in many places. The Navy used them from 1940 all the way through the Korean War in the 1950s.

Martin built 1,366 of these planes in total. They served across many battles, from Guadalcanal to Okinawa in the Pacific. The Mariner was one of the hardest-working patrol planes of the war.

Fun Facts

  • The Martin PBM Mariner could carry up to 8,000 pounds of bombs and torpedoes — heavier than three average cars!
  • The Mariner had eight machine guns placed in the nose, back, sides, and tail.
  • It could fly up to 19,800 feet high — nearly four miles above the ground!
  • Some Mariners could land on both water and regular runways, which was very rare.
  • The American Navy built 1,366 Mariners between 1940 and 1949.
  • The Mariner's wings were shaped like a seagull's wings, which helped it fly steadily.
  • Mariners helped track and damage about 14 German submarines during World War II.
  • The Mariner kept flying in Navy service all the way through the Korean War in 1956.

Kids’ Questions

How did the Mariner take off from water?

The Mariner had a smooth boat-shaped bottom called a hull. It also had two small floats under its wings to keep it steady. It would speed across the water and then lift into the air, just like a boat that can fly.

What did the Mariner do during World War II?

The Mariner flew long patrols over the ocean looking for enemy submarines. It dropped bombs and depth charges to stop them. It also helped support troops fighting in the Pacific islands.

Could the Mariner land on land as well as water?

Some versions of the Mariner had wheels that could fold in and out. This let them land on regular runways too. That made them special planes called amphibians.

How far could the Mariner fly?

The Mariner could fly up to 2,700 miles on one trip. That is longer than a flight from New York to Los Angeles! This long range made it great for ocean patrols.

Variants

PBM-3 / PBM-3C / PBM-3D
Mid-war production sub-variants 1942-1944. R-2600-12 engines, improved radar, additional defensive armament. About 600 built.
PBM-5 / PBM-5A
Late-war and post-war variants. R-2600-22 engines, improved radar, longer range. PBM-5A added retractable landing gear for amphibious operation. About 644 built.
Mariner GR.1A (Royal Australian Air Force)
RAAF service designation. About 41 PBM-3s delivered. Used in South-West Pacific operations 1944-1945.

Notable Operators

U.S. Navy
Primary user. WWII Atlantic and Pacific theatres + Korean War + post-war patrol service through 1956. Replaced by Martin P5M Marlin.
Royal Australian Air Force
About 41 PBM-3s. Operated by 41 and 43 Squadrons RAAF in the South-West Pacific 1944-1945.
Argentine Navy / Royal Netherlands Navy
Smaller post-war export operators. About 25 + 17 airframes respectively. Operated through the late 1950s.

Frequently Asked Questions

How was the PBM different from the PBY Catalina?

The Consolidated PBY Catalina was an older parasol-wing flying boat (first flew 1935), single-engine class but with twin engines mounted on a high parasol wing. The PBM Mariner (first flew 1939) was a more-modern gull-wing flying boat with twin engines integrated into the wing. The PBM had higher payload, better defensive armament, and faster speed; the PBY was more numerous and longer-ranged.

Did PBMs sink U-boats?

Yes — about 14 German U-boats were sunk or damaged by PBM attacks during the 1942-1945 Battle of the Atlantic. Atlantic-theatre PBMs operated from Bermuda, Iceland, the Azores, Natal (Brazil), and Trinidad to close anti-submarine air-coverage gaps in the central and South Atlantic.

How many PBMs were built?

1,366 airframes between 1940 and April 1949 at Martin's Middle River, Maryland plant. Production extended into 1949 with PBM-5A amphibian conversions for post-war U.S. Navy service.

Did a PBM rescue Indianapolis survivors?

Yes — Lt. R. Adrian Marks's PBM-5 of VPB-23 spotted the surviving sailors on 2 August 1945 (4 days after the 30 July 1945 sinking of USS Indianapolis by Japanese submarine I-58). Marks landed his PBM in heavy seas, picked up 56 survivors, and remained on the surface as a beacon for rescue ships. The Indianapolis sinking was the worst single loss of U.S. Navy life in WWII (about 880 sailors killed).

Are any PBMs still flying?

No — none airworthy. About 5 airframes survive in static-display condition, including the airframe at the Glenn L. Martin Maryland Aviation Museum at Middle River, Maryland (Martin's original plant). The National Naval Aviation Museum at Pensacola also holds one.

Sources

See Also