Remembering the Marshall Mars

I have to confess, I’m a sucker for flying boats, and especially really big ones. So when my brother showed up with these three original US Navy 8x10 prints of the Marshall Mars from 1948, I was ecstatic. As the Navy’s largest flying boats, with two that have survived into the 21st Century, the Mars story is one that’s been well-told, but even so, I figured these three photos were worthy of a post, especially since none of them show up in a Google image search.

This official US Navy photo is dated May 26, 1948 and per the handwritten notation on the back, shows "Refloating the Mars after engine change".

At the time they were built, the Martin Mars were the world’s largest production aircraft, and they continued to hold that title until the first flight of the Boeing 747. The Navy had originally ordered the type as an armed patrol bomber three years before America was drawn into WWII, but when war materialized, the Admirals realized that their needs in the Pacific were different - there just wasn’t the demand for a big, slow bomber, but there was a lot of logistics supplies to move over a lot of wide ocean. In addition, with the constant threat of U-Boats in the Atlantic, planners were intrigued by the idea of a large cargo plane that would be immune to German torpedoes.

Another US Navy photo, with the same date and caption as the one above.

The prototype XPB2Y-1R Mars, dubbed The Old Lady, had been delivered about a month before the attack on Pearl Harbor, but little was done quickly for the follow-on production order. When it finally came, it was for twenty aircraft configured to haul large amounts of cargo and troops across the Pacific, and the first production JRM-1 Mars wasn’t delivered until July 27, 1945, a month and a half before VJ Day (this was the first Hawaii Mars; she sank in the Chesapeake Bay during a landing accident only two weeks after delivery).

This official US Navy photo is dated May 25, 1948 and depicts "Beaching the Marshall Mars".

The Archive also has a couple small snapshots showing a Mars
at Pearl Harbor, but unfortunately these small prints are not
clear enough to tell which Mars is seen.

With the war over, the Navy cancelled most of the order. Six planes had been built, with several more in various stages of production. Unlike other Navy aircraft, the Mars were treated more like ships, and were given individual names, after various Pacific islands. The Marshall Mars (BuNo 76822) was the fourth production bird by serial number, but the second one delivered when it arrived in early February 1946, but would only serve for just over four years. Assigned to squadron VR-2 and based at Naval Air Station Alameda in California, the Marshall Mars set a new world record for payload lifted on her second flight, carrying 27,427 pounds from California to Hawaii (the previous record was held by the prototype, The Old Lady; it would later be broken by the last aircraft delivered, the Caroline Mars).

Another snapshot from Pearl Harbor, again not clear enough
to tell which Mars is shown.

While building the JRM Mars, Martin also considered the idea of offering a derivative model as a civilian airliner, which would have been powered by the larger R-4360 Wasp Major engines, the most powerful production piston engines built. Martin went so far as to order the long-lead-time components for the first airliner, including the engines. But the demand for large airliners simply didn't materialize after the war, and when Martin delivered the Caroline in 1948, they used the R-4360s, and the plane was designated a JRM-2. The bigger engines allowed for heavier loads to be carried farther, which pleased the Navy, and so shortly thereafter, the other JRM-1s were upgraded with the Wasp Majors as JRM-3s. I have not found a specific date for when this was accomplished on the Marshall Mars, but since our three photos are dated May 25 and 26, 1948, and the occasion for the operation shown was an "engine change", it's entirely possible that this is when the more powerful engines were installed.

On April 5, 1950 the Marshall was flying near Oahu when a fire broke out in one of the engines. On-board fire suppression systems did little to stem it, and the crew set down in Ke’ehi Lagoon, just off of Oahu, and then abandoned ship. The fire continued to spread until it reached one of the fuel tanks, which then exploded in rather dramatic fashion, and the airframe broke apart and sank.

The nose of the Marshall Mars as it looked in December 2004.
Courtesy NOAA/HURL

The Marshall Mars was rediscovered in 2004 by a joint survey team from the National Oceanic and Atmospheric Agency (NOAA), University of Hawaii and the National Park Service who set out to document various ocean-floor wreck sites off of Oahu, near the final resting spot of a Japanese midget sub which had been rediscovered in 2002.

Pieces of the Marshall Mars were first spotted in August, 2004, and then early the following December, over a two-day period, archeologists from the joint team explored various wreck sites using two submersibles from the Hawaii Undersea Research Laboratory (HURL; operated jointly by UofH and NOAA), the Pices IV and Pices V, documenting the sites’ location and condition and creating an inventory of surviving artifacts.

Courtesy NOAA/HURL

The Marshall Mars was found at a depth of about 1,400 feet, and although five and a half decades has led to a lot of marine creatures claiming the old plane as home, the name Marshall could still clearly be read on the nose section, which rests inverted on the ocean floor. The site, along with other similar flying boat wreck sites, are considered protected cultural resources under the jurisdiction of the National Park Service.

No post about the Mars would be complete, of course, without at least mentioning the current state of affairs with the two surviving Mars airframes, Hawaii Mars II and Philippine Mars, and a couple of fabulous photos of the former.

While not vintage photos, these two images, courtesy of my friend and fellow Antelope Valley aviation photographer Jim Mumaw, are destined to become classics. Jim traveled to Southern California’s Lake Elsinore in 2007 where the Hawaii was being used to fight a series of severe wildfires burning in the San Diego area, and he found that the Coulson crew had to use just about every foot of the lake for their operations, necessitating this rather dramatic approach over a hill to the edge of the water.

Copyright 2007 by Jim Mumaw, used with kind permission

Now, after a career as firefighting air tankers in Canada, a career which lasted much longer than their original one, time and technology have caught up with the two boats, and owner The Coulson Group has retired them from active service. One, the Philippine Mars, was destined for the National Naval Aviation Museum in Pensacola and has been beautifully repainted in her original US Navy blue livery.

Copyright 2007 by Jim Mumaw, used with kind permission

The fate of the other, the Hawaii was a bit more uncertain (at the time of this writing, a spate of wildfires has made it possible to bring the Hawaii out of retirement, and Coulson has secured a contract for its operation from the Provincial government), but since their contribution to Canada has been so long and so significant, there is a lot of interest in making sure she ends up in a Canadian museum. This past May, politics reared its ugly head when Canadian Heritage Minister Shelley Glover put the brakes on the transfer of the Philippine to the Florida museum, in order to ensure that the Hawaii would be staying in Canada. As of this writing, it doesn’t appear that the impasse has been settled...so stay tuned.

More information and resources

• NOAA article on the rediscovery of the Marshall
• A good history article on the Martin Mars
• A May 2015 article from Warbird News on the political gamesmenship surrounding the museum transfer.
• A period newsreel film on the Mars:

• A well-filmed recent documentary:

• A Coulson-produced promo video:

• A video of a water-drop demo and flyby: