PBJ-1D “White MB 3” with nose-mounted APS-3 radar
For a while, the US Navy (USN) had been looking to acquire a long-range, land-based aircraft for anti-submarine and maritime reconnaissance operations. However, this desire clashed with the USAAF’s policy of operating such aircraft. The USN later found itself in a situation where the USAAF needed a large aircraft factory to produce the B-29, and the only available plant was owned by the USN at Renton, which was being readied for Boeing PBB Sea Ranger production. In exchange for a batch of “navalised” Mitchells, B-24s, and Venturas, the Renton factory was handed over to the USAAF, and the PBB Sea Ranger was cancelled. The USN received 50 B-25Cs and 152 B-25Ds, which were moved from USAAF stocks and redesignated as the PBJ-1C and PBJ-1D, respectively, with the first of the former delivered in February 1943.
The initial batch of PBJs served with VMB-413 “The Flying Nightmares,” and most were modified to accommodate a Philco and Sperry APS-3 search radar inside a retractable radome positioned in place of the ventral turret. Several PBJs had the radar enclosed in a large radome mounted on top of the transparent nose. Only one B-25G was transferred to the USN as a PBJ-1G, while the B-25H and J were redesignated as the PBJ-1H and PBJ-1J, respectively, and were delivered in large numbers to operate alongside the earlier aircraft. In these models, the search radar was mounted in the ventral position or inside a wingtip radome. Towards the end of the war, several PBJ-1Js had their dorsal turrets removed to reduce weight.
The first PBJs entered service in March 1944 and were initially employed in long-range operations against enemy shipping attempting to break Japan’s blockade. For these missions, HVAR 5-inch rockets were generally used, carried on underwing racks. Later, VMB-612 flew from Iwo Jima using “Tiny Tim” rockets on night operations against enemy shipping.