The PBJ-1 was a navalized version of the USAAF B-25. It had its origin in a deal cut in mid-1942 between the Navy and the USAAF. The Navy was anxious to acquire a long-range, land-based heavy maritime reconnaissance and patrol aircraft capable of carrying a substantial bombload, but the USAAF had always resisted what it perceived as an encroachment into its jealously-guarded land-based bomber program. However, the USAAF needed an aircraft plant to manufacture its next generation of heavy bombers, the B-29 Superfortress. It just so happened that the Navy owned a plant at Renton, Washington, which was at that time being operated by Boeing for the manufacture of the PBB-1 Sea Ranger twin-engined patrol flying boat. The Army proposed that the Navy cancel the Sea Ranger program and turn over the Renton factory to them for B-29 production. In exchange, the USAAF would get out of the antisubmarine warfare business and would drop its objections to the Navy's operation of land-based bombers and the Navy would get "navalized" B-24 Liberators, B-25 Mitchells, and B-34/B-37 Venturas for use in maritime reconnaissance and antisubmarine warfare. The Navy readily agreed to this arrangement.
As part of the deal, fifty B-25Cs and 152 B-25Ds were transferred to the Navy from the USAAF. They were assigned the designations PBJ-1C and PBJ-1D respectively. The designation suffix of these and all subsequent PBJ-1 variants corresponded to the suffix of the corresponding B-25 model. The planes carried Navy serial numbers beginning with 34998. The first PBJ-1s arrived in February 1943. They were used by Marine Corps pilots, beginning with VMB-413. Many of them were equipped with a search radar with a retractable radome fitted in place of the ventral turret.
One B-25G was delivered to the Navy as PBJ-1G BuNo 35097.
Large numbers of B-25H and J variants were delivered to the Navy as PBJ-1H and PBJ-1J respectively. These aircraft joined, but did not necessarily replace, the earlier PBJs.
The PBJs were operated almost exclusively by the Marine Corps as land-based bombers. To operate the PBJ-1s, the US Marine Corps established a number of bomber squadrons, beginning with VMB-413, in March of 1943 at Cherry Point, North Carolina. Eight VMB squadrons were flying PBJs by the end of 1943, forming the initial Marine Medium Bombardment Group. Four more squadrons were in the process of formation in late 1945, but had not yet deployed by the time the war ended.
PBJ-1Hs served with VMB-412, VMB-413, VMB-423, VMB-433, VMB-443, VMB-453, VMB-463, VMB-473, VMB-483, VMB-611, VMB-612, VMB-614, VMB-621, VMB-622, VMB-623, VMB-624. VMB-413, 423, 433, 443, and 611 operated in the Central and South Pacific, and BMB-612 and 613 operated in the Central Pacific.
Operational use of the Marine Corps PBJ-1s began in March of 1944. The Marine PBJs operated from the Philippines, Saipan, Iwo Jima and Okinawa during the last few months of the Pacific war. Their primary mission was the long range interdiction of enemy shipping that was trying to run the blockade which was strangling Japan. The weapon of choice during these missions was usually the five-inch HVAR rocket, eight of which could be carried on underwing racks. Many of the PBJ-1C and D versions carried a rather ugly, bulbous antenna for an APS-3 search radar sticking out of the upper part of the transparent nose. On the PBJ-1H and J, the APS-3 search radar antenna was usually housed inside a ventral or wingtip radome. Some PBJ-1Js had their top turrets removed to save weight, especially toward the end of the war when Japanese fighters had become relatively scarce.
In mid-1945, VMB-612, based on Iwo Jima, flew specially modified PBJ-1Js capable of carrying the 11.75-inch Tiny Tim rocket. Two Tiny Tim rockets could be carried, one on each side of the fuselage above the bomb bay doors. Launch was by free fall, and ignition was actuated by a lanyard that was pulled after the rocket had dropped a certain distance. After launch, the bomb bay doors could be opened for conventional bomb drops. These Tiny Tim rockets were used during nighttime strikes against southern Japan in the interim between the dropping of the second atomic bomb on Japan and the final agreement of surrender on August 14.
In 1945, the Naval Ordnance Test Station at China Lake, California carried out a joint program with the Harvey Machine Company for the development of an automatic launcher for five-inch spin-stabilized rockets from the nose of a PBJ-1J. Two rotating drums carried five spin-stabilized rockets each. The rockets could be released in salvoes of five or singly at 3/10 sec intervals. A deflector tube ported the blast from the rocket exhaust downward out of the airplane at the aft end of the nose section. PBJ-1J 35849 (ex USAAAF 44-30980) was selected as a test aircraft for the program. Ground and aerial firing tests failed to prove the concept sufficiently effective to warrant production.
PBH-1H 43-4700 (BuNo 35277) was modified for aircraft carrier catapult launch and arrest retrievals. The first landings and catapult takeoffs took place aboard the USS Shangri La (CV-38) on November 15, 1944. Although the experiment was successful, no further work on a carrier-based Mitchell took place since American advances in the Pacific made such an aircraft unnecessary.
Navy (as distinct from Marine Corps) use of the PBJ-1 was limited to a few aircraft being used after the war for test and development work up to 1948.
The following is a list of serial numbers of USAAF B-25s turned over to the US Navy as PBJ-1s:
41-30533/30847 North American B-25D-20 Mitchell 30730/30754 to USN as PBJ-1D 35048/35072 42-64502/64701 North American B-25C-20 Mitchell 64502/64506 to USN as PBJ-1C 34998/35002 64602/64621 to USN as PBJ-1C 35003/35022 42-64702/64801 North American B-25C-25 Mitchell 64708/64732 to USN as PBJ-1C 35023/35047 42-64902/65101 North American B-25G-5 Mitchell 65031 to USN as PBJ-1G 35097 42-87138/87452 North American B-25D-25 Mitchell 87157/87180 to USN as PBJ-1D 35073/35096 87181/87205 to USN as PBJ-1D 35098/35122 43-3280/3619 North American B-25D-30 Mitchell 3320/3344 to USN as PBJ-1D 35123/35147 3570/3605 to USN as PBJ-1D 35148/35183 43-3620/3869 North American B-25D-35 Mitchell 3651 to USN as PBJ-1D 35184 3655 to USN as PBJ-1D 35185 3771/3778 to USN as PBJ-1D 35186/35193 3837/3843 to USN as PBJ-1D 35196/35202 43-3870/4104 North American B-25J-1-NA Mitchell 3985,3986 to USN as PBJ-1J 35194,35195 43-4405/4704 North American B-25H-5 Mitchell 4471 to USN as PBJ-1H 35280 4482 to USN as PBJ-1H 35281 4492 to USN as PBJ-1H 35282 4530 to USN as PBJ-1H 88872 4542/4544 to USN as PBJ-1H 35283/35285 4591/4593 to USN as PBJ-1H 35286/35288 4638 to USN as PBJ-1H 88873 4654 to USN as PBJ-1H 88874 4655 to USN as PBJ-1H 35292 4656 to USN as PBJ-1H 35259 4658 to USN as PBJ-1H 35293 4659/4660 to USN as PBJ-1H 35250/35251 4661 to USN as PBJ-1H 88875 4664/4666 to USN as PBJ-1H 35294/35296 4667 to USN as PBJ-1H 35252 4669 to USN as PBJ-1H 35253 4670 to USN as PBJ-1H 35260 4671/4673 to USN as PBJ-1H 35254/35256 4675 to USN as PBJ-1H 35261 4676 to USN as PBJ-1H 35257 4682/4684 to USN as PBJ-1H 35289/35291 4685/4702 to USN as PBJ-1H 35262/35279 4703 to USN as PBJ-1H 88876 4704 to USN as PBJ-1H 88877 43-4705/5104 North American B-25H-10 Mitchell 4705 to USN as PBJ-1H 89051 4709 to USN as PBJ-1H 35297 4710 to USN as PBJ-1H 35258 4711/4883 to USN as PBJ-1H 88878/89050 5028/5047 to USN as PBJ-1H 89052/89071 43-27473/27792 North American B-25J-1 Mitchell 27511/27515 to USN as PBJ-1J 35203/35207 27681/27687 to USN as PBJ-1J 35208/35214 43-27793/28112 North American B-25J-5 Mitchell 27904/27910 to USN as PBJ-1J 35215/35221 44-28711/29110 North American B-25J-15/17 Mitchell 28792/28801 to USN as PBJ-1J 35229/35238 29064/29073 to USN as PBJ-1J 35239/35248 44-29111/29910 North American B-25J-20/22 Mitchell 29276 to USN as PBJ-1J 35249 29277/29285 to USN as PBJ-1J 38980/38988 29290/29299 to USN as PBJ-1J 38989/38998 29510/29513 to USN as PBJ-1J 64969/64972 29604/29617 to USN as PBJ-1J 38999/39012 29618/29623 to USN as PBJ-1J 64943/64948 29788/29794 to USN as PBJ-1J 64949/64955 29801/29807 to USN as PBJ-1J 64956/64962 29814/29819 to USN as PBJ-1J 64963/64968 29870/29884 to USN as PBJ-1J 64973/64987 29897/29901 to USN as PBJ-1J 64988/64992 44-29911/30910 North American B-25J-25/27 Mitchell 30353/30356 to USN as PBJ-1J 35821/35824 30509/30531 to USN as PBJ-1J 35798/35820 30703/30710 to USN as PBJ-1J 35830/35837 30716/30718 to USN as PBJ-1J 35838/35840 30849/30851 to USN as PBJ-1J 35877/35879 30856 to USN as PBJ-1J 35880 44-30911/31510 North American B-25J-30/32 Mitchell 30961/30964 to USN as PBJ-1J 35841/35844 30972/30975 to USN as PBJ-1J 35845/35848 30975 (BuNo 35848) converted into prototype for trainer. w/o 3/25/1950 30980/30991 to USN as PBJ-1J 35849/35860 31089/31104 to USN as PBJ-1J 35861/35876 31277/31296 to USN as PBJ-1J 35881/35900 31444/31463 to USN as PBJ-1J 35901/35920
The following is a list of the BuNos of Navy PBJ-1s, with USAAF equivalent serials:
34998/35047 North American PBJ-1C Mitchell Navy equivalent of B-25C were USAAF 42-64502/64506,42-64602/64621, 42-64708/64732 35048/35096 North American PBJ-1D Mitchell Navy equivalent of B-25D were USAAF 41-30730/20754,42-87157/87180. 35097 North American PBJ-1G Mitchell Navy equivalent of B-25G (42-65031). 35098/35193 North American PBJ-1D Mitchell Navy equivalent of B-25D were USAAF 42-87181/87205,43-3302/3344, 43-3570/3605,43-3651,43-3655,43-3771/3778 35194/35195 North American PBJ-1J Mitchell Navy equivalent of B-25J were USAAF 43-3985/3986 35196/35202 North American PBJ-1D Mitchell Navy equivalent of B-25D were USAAF 43-3837/3843 35203/35249 North American PBJ-1J Mitchell Navy equivalent of B-25J. Were USAAF 43-27511/27515, 43-27681/27687, 43-27904/27910, 43-28174/28180, 44-28792/28801, 44-29064/20073, 44-20276 35250/35297 North American PBJ-1H Mitchell Navy equivalent of B-25H were USAAF 43-4659/4660, 43-4667, 43-4669, 43-4671/4673, 43-4676, 43-4710, 43-4656, 43-4670, 43-4675, 43-4685/4702, 43-4471, 43-4482,43-4492,43-4542/4544,43-4591/4593, 43-4682/4684,43-4655,43-4658,43-4664/4666, 43-4709. 35798/35920 North American PBJ-1J Mitchell Navy equivalent of B-25J. Were USAAF 44-30509/30531,44-30353/30356, 44-30693/30697,44-30703/30710, 44-30716/30718,44-30961/30964, 44-20972/30975,44-30980/30991, 44-31089/31104,44-30849/30851, 44-30856,44-31277/31296,44-31444/31463 38980/38999 North American PBJ-1J Mitchell Navy equivalent of B-25J. Were USAAF 44-29277/29285, 44-292290/29299, 44-29604/20617. 64943/64992 North American PBJ-1J Mitchell Navy equivalent of B-25J. Were USAAF 44-20618/29623, 44-29788/29794, 44-29801/29807, 44-29814/29819, 44-29510/29513, 44-29870/29884, 44-29897/29901. 88872/88999 North American PBJ-1H Mitchell Navy equivalent of B-25H. Were USAAF 43-4530,4638,4654,4661,4703,4704, 4711/4883,4705,5028/5047