In search of new orders Martin company decided to enlarge its successful Mariner flying boat patrol bomber to produce the huge four-engined XP2BM-1. First flown at the end of 1941 and tested by the US. Navy, a change of operational patrol aircraft policies soon condemned its posible future. It was never put into production as such, but became the prototype for the later JRM Mars transport flying boats. Only a total of seven were built for the US.Navy. In the early 1960s four JRMs were converted into fire flying tankers. One of them, “Hawaii Mars”, still sporadically earns it keep as flying tanker.
The XPB2M-1 Mars prototype flying boat patrol bomber just out of the oven with a Piper J-3 Cub placed on its wing to show scale. It was indeed humongous.