The 'Flawed' American Flying Boat That Sank More Ships Than Any Bomber

On June 30, 1942, four hundred fifty nautical miles west of Bermuda, Lieutenant Richard Schreder lifted a slow, ugly, twin-engine flying boat off a flat blue Atlantic and went hunting. The aircraft was a Martin PBM Mariner — the largest twin-engine flying boat in the world, a machine the Royal Air Force had just rejected without flying a single operational sortie, a design senior U.S. Navy officers dismissed as a compromise. Vectored by a radio direction-finding fix, Schreder dove out of the cloud base onto the surfaced U-158 and killed her with a single salvo of depth charges. Aboard the submarine was Knight's Cross holder Erwin Rostin, who had sunk seventeen Allied ships in one patrol. Fifty-four Germans and two American prisoners died in ten seconds. There were no survivors. The United States Navy had almost canceled this aircraft. The XPBM-1 prototype suffered severe tail flutter and dangerous yaw instability, and the iconic inward-canted twin tail that became its signature silhouette was not a design choice — it was a repair. By the end of the war the PBM had been credited with sinking or sharing in the destruction of ten German U-boats, roughly thirty-four percent of every U-boat kill scored by U.S. Navy patrol aviation, and had sunk more enemy ships than any American patrol bomber of any other type. This is the story of how a flying boat dismissed as flawed outscored the long-range land-based bombers that were supposed to make her obsolete. — MARTIN PBM-3D MARINER SPECIFICATIONS Engine: 2 × Wright R-2600-22 Twin Cyclone 14-cylinder air-cooled radial (1,900 hp each) Max Speed: 211 mph at 16,100 ft (340 km/h) Cruise Speed: 135 mph (217 km/h) Service Ceiling: 19,800 ft Range: 2,240 miles Endurance: 12–14 hours patrol Armament: 8 × .50-cal Browning M2 in five powered positions; up to 8,000 lb bombs, depth charges, or Mk 24 homing torpedo Wingspan: 118 ft / Length: 79 ft 9 in Empty Weight: 33,175 lb / Loaded: 58,000 lb Construction: All-metal stressed-skin, inverted gull wing, deep two-step planing hull Unit Cost: approximately $414,000 Total Built: 1,366 (all variants) CONSOLIDATED PB4Y-2 PRIVATEER (RIVAL COMPARISON) Engine: 4 × Pratt & Whitney R-1830-94 (1,350 hp each) Max Speed: 245 mph Range: 2,900 miles Service Ceiling: 20,700 ft Armament: 12 × .50-cal in six powered turrets; up to 12,800 lb ordnance Total Built: 739 KEY OPERATIONAL DATA Share of all U.S. Navy patrol-aviation U-boat kills credited to the PBM: 34% (10 of 29) First PBM U-boat kill: June 30, 1942, Lt. Richard Schreder, VP-74, vs U-158 U-615 hunt, August 1943: largest aircraft hunt ever mounted for a single submarine Japanese submarine I-177 crippled October 1, 1944 with a Mk 24 "Fido" homing torpedo VPB-18 anti-shipping record: 44 ships sunk in three months at Kerama Retto Okinawa air-sea rescue: PBMs saved 81 of 132 downed airmen — more than all other types combined Mariner squadrons operating west of the Marianas by July 1945: 13 Surviving intact examples worldwide: 1 (Pima Air & Space Museum, Tucson, Arizona) Last military Mariner retired: Uruguayan Navy, February 3, 1964 — SOURCES AND HISTORICAL NOTES This video draws on official United States Navy squadron operational records and published naval aviation histories. Key references include Richard A. Hoffman's "The Fighting Flying Boat: A History of the Martin PBM Mariner" (Naval Institute Press, 2004), the Naval History and Heritage Command's "Dictionary of American Naval Aviation Squadrons," and Norman Polmar's "A Very Able Mariner" in Naval History Magazine (December 2007). U-boat kill attributions cross-referenced with uboat.net and the Naval History and Heritage Command appendix "Submarines Sunk by Patrol Aircraft During World War II." Pacific operational history drawn from U.S. Naval Institute Proceedings ("The Role of the Patrol Bombers," September 1947; "Low and Slow," September 1949), the American Aviation Historical Society Journal (Fall 2003), and the Bureau of Aeronautics Kammen Report air-sea rescue figures. Specifications cross-referenced with the National Air and Space Museum and Jane's All the World's Aircraft 1945/46. The corrected U-604 attribution — a PV-1 Ventura kill, not a PBM kill — follows Clay Blair's "Hitler's U-Boat War." Viewer corrections welcome — accuracy matters. #WWII #MilitaryAviation #PBMMariner #FlyingBoat #USNavy #UBoat #WW2History #NavalHistory #AviationHistory #WarHistory