Lost Navy boat: Conestoga's watery grave

Ninety-five years ago, the Navy tugboat USS Conestoga left a California naval yard bound for Pearl Harbor, on the way to a new duty station in American Samoa.

Then it just disappeared, along with its 56-person crew..

It was in the middle of peacetime; it was the modern era ... the 20th century; and searches turned up nothing. Only three other lost Navy ships fit those criteria.

For decades, the Conestoga's disappearance confounded shipwreck researchers. But in March 2016, the Navy announced that the Conestoga has been found, with remarkable underwater photos as proof.

This modern painting of the Conestoga imagines its final hours in March 1921, pounding through large waves during a gale.

Lost and found

The first real clue about the fate of the Conestoga came in September 2009, after a joint survey from the National Oceanic and Atmospheric Administration and the geo-survey firm Fugro turned up this image in the Farallon Islands.

The Farallon Islands, off the California coast, are officially part of the city and county of San Francisco.

Experts documented a probable shipwreck with an estimated length of 170 feet, at a depth of 185 feet.

Conestoga's stern

In 2014 and again in 2015, a team of researchers launched expeditions that would finally confirm the fate of the Conestoga.

Among the photos: this image of the stern. The white rim comes from heavy marine growth, mostly white plumose sea anemones. The rudder is positioned hard to starboard, and the steering quadrant on deck hard to port.

Port bow with a new resident

An official NOAA report posits that the tug foundered in heavy, shark-infested seas and became waterlogged, though precise details remain elusive.

Here's the port bow of the wreck, showing the rub rail mounts, an anchor cable hole, marine growth ... and a giant Pacific octopus.

Telltale fantail

The wreck is heavily draped in a variety of sea animal growth. But the Conestoga's fantail still offered up a key clue. A careful examination by researchers showed raised metal letters spelling part of the vessel's name. Peeking out from the marine growth were the outline forms of what appeared to be the letter "T" with an adjacent "O."

Boiler view

Here's a view the boiler compartment, showing part of one boiler and collapsed debris from the upper works of the tug.

Waterlogged engine

Here's the 1,000-horsepower, triple steam engine inside the hull. The artifact help date the shipwreck, along with its coal-fired twin Scotch boilers. Forward of the steam engine is a partial bulkhead, with remnants of coal in the coal bunker.

Inside the engine room space: Steam pipes, portholes from the upper deckhouse and a marine toilet.

Conestoga's gun

Top: The Conestoga gunnery department posing with the tugboat's main battery, a three-inch, 50-caliber naval gun, in San Diego, California, in 1921.

Bottom: The current position of the gun inside the shipwreck near the forecastle.

"Smoking" gun

The gun's support platform had fallen from its original position in front of the pilot house, through the main deck.

The gun proved key in identifying the wreck as the USS Conestoga.

Getting the first clues

The first expedition to get close to the lost tug came in September 2014, aboard the NOAA research vessel Fulmar.

The workhorse in the expedition was a Phantom HD2 remotely operated vehicle (ROV), which comes equipped with laser rulers, sediment blasters and the ability to deliver color video at a depth of 1,000 feet.

Steering gear

This steam steering gear is believed to have fallen through Conestoga's main deck, from its its original position below the pilot house.

Stem view

Fish swim past a starboard bow view of the Conestoga;the top of the stem is visible.

A researcher that runs itself

Another technical hero of the Conestoga expeditions: A self-operating underwater probe, seen being operated here by Teledyne SeaBotix's Cyril Poissonnet.

The probe was launched by Poissonnet off the stern of the Fulmarduring a second expedition in October 2015.

The wreck, re-imagined

This painting of the shipwreck site is based on interpretations of maritime archaeologists from NOAA and the Office of National Marine Sanctuaries. The shipwreck is located off Southeast Farallon Island and lies in the federally protected waters of Greater Farallones National Marine Sanctuary.

All hands lost

This 1921 Navy photo shows the Conestoga's company beside and on the tug in San Diego, California, just weeks before the ship was lost.

It is believed to be the last full portrait of the tug's crew.

Lost at sea

Lt. Ernest L. Jones, the commanding officer of the Conestoga, is one of the 56 hands lost.

Wendell Plummer, Seaman Second Class

Seaman Wendell Plummer was also aboard the Conestoga.

The U.S. Navy has said it's working on managing and protecting the wreck as a military gravesite, and as a historic site within the Greater Farallones National Marine Sanctuary.

Charles Joseph Balint, Seaman

Also aboard the tug: Seaman Charles Joseph Balint.

The U.S. government doesn't expect that the site of the wreck will face much disturbance; the wreck lies in an area heavily populated by white sharks who feed on the nearby marine mammal population.

"That fact, as well as propriety, suggests that Conestoga and any crew remains will remain undisturbed," an official NOAA report states.

Edward Wilson, Mess Attendant First Class

Edward Wilson, mess attendant 1st class, also was lost in the wreck.

"There will likely never be a complete understanding of why the tug foundered," the NOAA report states. "[But] for the families, what is now clear is exactly where their relatives lie at rest, inside the tugboat where they paid the ultimate price for their service to country."