Home WORLD Martin JRM-3 Mars World’s Largest Production Seaplane

Martin JRM-3 Mars World’s Largest Production Seaplane


The Martin JRM Mars is a large, four-engined cargo transport seaplane, designed and built by the Martin Company for the United States Navy during WW II.Built in 1945, Hawaii Mars II is the world’s largest flying boat, that can still fight forest fires.

image: Platinum Fighter Sales

It was the largest Allied flying boat to enter production, although only seven were built. The United States Navy contracted the development of the XPB2M-1 Mars in 1938 as a long-range ocean patrol flying boat, which later entered production as the JRM Mars long-range transport.

Four of the surviving aircraft were later converted for civilian use to firefighting water bombers. Two of the aircraft still remain based at Sproat Lake just outside of Port Alberni, British Columbia, although neither is operational.


The aircraft can carry 27,276 litres of water and each deployment can cover an area of up to 1.6 hectares. The aircraft can also carry up to 2,270 litres of foam concentrate for gelling the load drop. The airplane is powered by four Wright R-3350-24WA Duplex Cyclone 2500 hp Radial Engines.