Well before the United States entered World War II, the Navy started a program to develop a long-range flying boat, able to cover the vast expanse of the Pacific Ocean.

To build the large PBB, Boeing started construction of a new lakeside factory in Renton, Washington, that was owned by the US Navy.

[1] To achieve the desired long range, the PBB became a fairly large aircraft, with a wingspan of 139 feet 8+1⁄2 inches (42.59 m) and a crew of ten.

[1] Despite its size, it was powered by just two Wright R-3350 Duplex Cyclone radial engines, driving three-bladed Curtiss Electric propellers.

The lower hull was divided with seven watertight compartments, and a short upper deck provided seating for the cockpit crew.

The NAF duly prepared a design for a Mark VII catapult that would be able to launch a fifty-ton PBB-1 at a speed of 130 miles per hour.

However, in the summer of 1942, while development of the Mk.VII catapult was still ongoing, the Navy cancelled the project because it considered JATO assistance at takeoff more practical.