Fortunately, the story of the Mars did not end here. After being assigned to transport squadron VR-2 out of Naval Air Station Alameda, Calif., the XPB2M-1R, now known as Old Lady, proved to be an excellent freight hauler, routinely carrying up to 10 tons of cargo between Hawaii and California. BuAer liked it well enough to order 20 new aircraft, designated JRM-1s, in June 1944. Also known as the Model 170A, the JRM-1 differed from the prototype in that it had a single vertical fin, a hull lengthened by 3 feet, fewer internal bulkheads and new cargo-handling equipment. The installation of 2,500-hp R-3350-24W engines, plus new four-bladed propellers, boosted takeoff weight to 148,500 pounds. The first production JRM-1, christened Hawaii Mars, was delivered in late July 1945, but was destroyed only two weeks later in a landing accident on Chesa­peake Bay. Four more JRM-1s were delivered to the Navy before the end of the year. As a result of V-J Day cutbacks, however, the original order was reduced to just six aircraft.

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Martin also had aspirations to sell an airliner version of the Mars, the 79-seat Model 170-24A, to be powered by Pratt & Whitney R-4360 engines. But when the postwar market for civilian flying boats failed to materialize, the project was abandoned. The sixth and final Mars built, the JRM-2, was completed in 1946 with the 3,000-hp R-4360-4 power plants originally intended for the Model 170-24A airliner. The JRM-2’s increased power permitted a takeoff weight of 165,000 pounds and added more than 10,000 pounds to its useful load. Its fully reversible propellers on the two inboard engines allowed the aircraft to back up or stop within shorter distances. During the late 1940s, in order to bring them up to the increased payload capability of the JRM-2, the four remaining JRM-1s were modified to allow installation of R-4360 engines and were redesignated JRM-3s.

Destined for Pacific service, all five JRMs were assigned to VR-2 at NAS Alameda. VR-2’s mission during the war had been to provide a fast means of moving critical supplies, spares and personnel over the vast transoceanic distances of the Pacific theater. In addition to its prior experience with the XPB2M-1R, the unit had been operating other types of large flying boats such as the Mariner and the cargo adaptation of the Consolidated PB2Y Coronado, so the big Mars was a logical fit. Once operational, the JRMs were used primarily to transport cargo and personnel on the regular run between Alameda and Pearl Harbor. But during their tenure with VR-2, the big flying boats did occasionally divert from their routine duties to chalk up some impressive records: In 1948 Caroline Mars carried a payload of 68,282 pounds (twice the normal load) from Baltimore to Cleveland; in 1950 the same plane transported 144 Marines from San Diego to Honolulu; and in 1949 Marshall Mars carried a record 301 servicemen plus a crew of seven from San Diego to Alameda.

On May 5, 1950, while Marshall Mars was flying off Diamond Head in Hawaii, one of its engines caught fire and the aircraft was forced to make an emergency landing. Although the crew escaped injury, the big flying boat was entirely consumed by flames. Other than this incident, the operational record of VR-2’s JRMs was nearly flawless, and the remaining four aircraft continued to provide safe, reliable and economical air transportation.

In 1956 the Navy decided to discontinue cargo operations with flying boats, and the final Mars military flight took place on August 22, 1956. Thereafter, the four JRMs were hauled out of the water on beaching gear and consigned to the boneyard at Alameda. After sitting idle for nearly three years, the big aircraft were offered for sale as scrap. Similar to the fate shared by so many other old airplanes that had theoretically outlived their usefulness, it appeared that the next step for the mighty Mars was the chopper, then oblivion—almost.

Enter Dan McIvor, a veteran Canadian corporate pilot. During the 1950s western Canada had been plagued by forest fires that destroyed thousands of acres of timberland, and McIvor was one of small group of pioneers who were developing the concept of using aircraft to fight them. When he learned that the U.S. Navy was selling off four Martin Mars flying boats at scrap metal prices, he figured the big planes would be ideally suited to serve as firefighters. Upon further inquiry, however, he discovered that all four had already been sold to a scrap dealer (who apparently planned to part them out) for a total of $23,650. After making a convincing case to his financial backers—several of Canada’s major lumber corporations—he was able to persuade the scrap dealer to resell the big airplanes for $25,000 each, and ownership of the four JRMs was subsequently transferred to Forest In­dustries Flying Tankers (FIFT).

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