Tuesday, October 2, 2012

Renton's Celebrity WWII Airplane Wreck

A Martin PBM-5 'Mariner' in flight, 1945.

On May 6, 1949, a US Navy Martin 'Mariner' PBM-5 aircraft (BuNo 59172) was being relocated from the naval station then based at Sand Point to the Boeing Renton facility for storage. The plane, a 'flying boat' design, was taxiing about 100 yards off the large seaplane ramp near the mouth of the Cedar River when its starboard wing pontoon struck a semi-submerged floating log and broke off, causing an immediate, severe list. An open side cargo door caused lake water to stream into the fuselage and the crew scrambled to safety as the plane filled with water, quickly rolling starbard as it sank. It settled upside down on the muddy lakefloor in 65-70 feet of water.

A Martin PBM-5 'Mariner' at Renton, 1946

Over time, six to eight feet of thick, gooey silt from the river accumulated over the 737-sized plane's wings and engine nacelles, leaving the wings, engines and about half the fuselage and most of the tail buried under the muck. By the 1970's, a few hardy sport divers had visited the plane in the chilly, dark-as-night depths, but it was not until about 1980 that a band of amature would-be salvors began to remove relics from the plane--including the two Browning M-2 .50 waist machine guns, which they turned over to authorities--and began humble, wholly inadequate dredging efforts in an attempt to clear the tons of mud holding the plane on the bottom. Unlike the US Army (There was not yet a US Air Force during WWII) the US Navy made it clear that it did not want private individuals recovering its crashed aircraft, by then already considered valuable museum pieces.
The tail and rear .50 turret that were broken off the Mariner submerged near Renton, on display at the Pima Air Museum

My friends and I--then still in our teens--managed to locate the plane in late 1982 and made over 40 dives on it, culminating in the 1983 removal of the two Browning M-2 .50 machine guns from the nose turret, then under about five feet of mud. after being thoroughly shown off to friends and family, those big machine guns were also turned over to federal authorities.
Rusty rear .50 machine guns in turret. These guns spent most of their years on the bottom under the thick mud. Combined with the low oxygen and fresh water, they are in fairly good shape--the guns we removed were still able to cycle rounds after we painstakingly removed the mud and corrosion conglomerate using Break Free (TM) and old toothbrushes.  

In 1990, the Naval Reserve Mobile Diving Salvage Unit One's Detachment 522 (NRMDSU-1 Det 522), of Naval Station Everett, made an unsuccessful attempt to salvage the plane for the National Museum of Naval Aviation, in Pensacola, Florida. That effort was abandoned after a diver died.

The PBM's propeller blades and hub spent years under the muck, but were exposed during a 1990s US Navy salvage attempt.

The Navy made a second salvage attempt in 1996 and removed many tons of material from atop the wings and around the fuselage. That effort involved a veritable alphabet soup of bureaucrats and agencies, including: Naval Historical Center; the Mariner/Marlin Association; the Washington State Office of Archaeology and Historic Preservation; the U.S. Army Corps of Engineers, Seattle District; and the Advisory Council on Historic Preservation, Western Review Office and even The Boeing Corporation.

A sonar image of the PBM on the lakefloor shows the depressions created by dredging above wings and tail areas.

Unfortunately, even with all the bureaucratic personnel involved in the project and the sizable sums of government money invested, all that effort achieved was major damage to the plane: It ripped the tail off the fuselage and then pretty much declared victory for the taxpayers.

Navy divers placed wire grates over the various openings in the fuselage to keep sport divers out of the interior and what was left of the the tail and tail turret were shipped to the Pima Air & Space Museum, adjacent to Davis–Monthan Air Force Base in Tuscon, Arizona.

Today, only one complete Mariner exists. Many of us believe BuNo 59172 would better serve the public as a restored static display than by being allowed to corrode away to nothing on the bottom of Lake Washington.
 Front view of the rear turret and .50 guns.

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