The Boeing PB-1 was the US Navy designation for the B-17 Flying Fortress. Forty Eight B-17Gs were acquired by the navy during 1945 to be used to carry airborne early warning radar. In order to give more warning against Japanese attacks, the US Navy was posting radar-equipped picket ships ahead of the main fleet, but those ships were themselves suffering unacceptably high losses. The navy decided to replace these vulnerable ships with aircraft carrying APS-20E search radar.
A number of different aircraft were considered for the role. The B-17 was chosen because it could carry the radar and retain its guns, considered essential if the aircraft was to survive over the Sea of Japan. The war ended before the radar equipped aircraft could enter service. Navy Squadron VPB-101 received its first PB-1 (without radar) in September 1945, the month after Japan had surrendered, and its first radar equipped PB-1W in January 1946
After the war the PB-1W was used to mount patrols between Newfoundland and Iceland and around the Azores, guarding against a possible Soviet attack. Other aircraft were used for meteorological research and on hurricane patrols. The PB-1W remained in service after the majority of other American B-17s had been scrapped.