USNS Navajo (T-ATF-169)

USNS Navajo (T-ATF-169) was a United States Navy Powhatan-class tugboat operated by the Military Sealift Command which was in service from 1980 to 2016. She spent the bulk of her career in the Pacific and is currently moored in Pearl Harbor, awaiting disposal.

Construction and characteristics
The contract for the first four Powhatan-class tugs was awarded to Marinette Marine Co. on 12 September 1975. The contract price for the four ships was $30.5 million. Navajo was the fourth ship built under this initial contract award. The ship was laid down on 14 December 1977 at the company's Marinette, Wisconsin shipyard. Navajo was launched on 20 December 1979, and delivered to the Navy on 13 June 1980.

Her hull was built of welded steel plates. She was 225 ft long at the waterline and 240 ft overall, with a beam of 42 ft, and a draft of 15 ft. She displaced 2,260 tons fully loaded.

As originally built, Navajo had two controllable-pitch Kort-nozzle propellers for propulsion. She had two 20-cylinder Diesel engines, GM EMD 20-645F7B, which provided 4,500 shaft horsepower. These would drive the ships at 15 knots. She also had a 300-horsepower bow thruster to improve maneuverability.

Electrical power aboard the ship was provided by three 400 Kw generators. These were powered by four Detroit Diesel 8v-71 engines.

Powhatan-class tugs had global range in order to support the U.S. fleet across oceans. Navajo's tankage was consequently large. She could carry 206,714 U.S.gal of Diesel oil, 6100 U.S.gal of lube oil, and 6000 U.S.gal of drinking water. Her unrefueled range at 13 knots was 10,000 mi

Navajo's aft deck was largely open to accommodate a number of different roles. It had 4000 sqft of working space. One of the missions of a fleet tug was to tow damaged warships back to port. She was equipped with a SMATCO 66 DTS-200 towing winch for service as a towboat. The towing system could accommodate either wire rope or synthetic-fiber hawsers and produce as much as 90 short tons of bollard pull. She had a 10-ton capacity crane for moving loads on the aft deck. There were connections to bolt down shipping containers and other equipment.

Like all MSC ships, Navajo was crewed by civilian mariners. At launch, her complement was 16 civilian crew and a 4-person military detachment of communications specialists. The ships could accommodate an additional 16 people aboard for transient, mission-specific roles.

All the ships of the Powhatan-class were named after Native American tribes. Navajo was named after the Navajo people, of the United States southwest.

Service history
An engine room fire disabled USNS Taluga northwest of San Diego in April 1981. Navajo was dispatched to bring her back to port. On 10 June 1981, Navajo, took USNS Hudson under tow. She was dead in the water off San Nicholas Island at the time.

The large, open aft deck of the Powhatan-class tugs, combined with the 10-ton crane made them capable platforms for salvage missions. Navajo was called upon several times in this role. In July 1988 she assisted in the recovery of a MH-53E Sea Dragon helicopter which crashed off San Francisco. In 2016 she assisted USNS Salvor in recovering the wreckage of two MH-53E helicopters that crashed off Hawaii.

On 1 September 1992, Navajo towed USS White Plains into deeper water after the ship broke her moorings and went aground in Apra Harbor, Guam during Typhoon Omar.

Unexploded ordnance from World War II was discovered off Hilo Bay, Hawaii. Navajo served as a dive platform for Navy crews collecting and detonating the rounds in September 2000.

In September 2008 Navajo exercised with the Chilean Navy's submarine CS Simpson with the Navy's new submarine rescue diving and recompression system.

Navajo was used as a dive platform in a joint US Navy/Indian Navy salvage exercise, SALVEX 2009, in November 2009.

In December 2010 and January 2011, the Navy's deep-ocean recovery system CURV-21 was embarked on Navajo. She was able to determine that a deep water sensor was not stuck on its anchor on the sea bottom at more than 16,000 ft deep. In a second mission, she was unable to locate an Air Force asset.

In 2003 Navajo towed the Navy's Floating Instrument Platform into San Diego Harbor.

On 28 July 2012 the ship was conducting training near the entrance to Pearl Harbor, Hawaii when a parted mooring line caused the ship to dump 8,000 pounds of expensive anchor, chain, and heavy rope on the ocean floor 150 feet below. The equipment was recovered on 9 August 2012.

In May 2016, Navajo towed the missile tracking barge Mobile Area Targeting Support System (IX524) into Pearl Harbor.

Decommissioned ship tows
Vessels which are retired from Navy service are often towed to various inactive ship maintenance facilities where they are held in reserve. Ultimately, they are towed on to their final fate. These decommissioned ships do not have full crews and cannot sail under their own power. Navajo was frequently employed to tow decommissioned ships.

RIMPAC participation
"Rim of the Pacific" (RIMPAC) is a multinational naval exercise hosted every two years in Hawaiian waters. It typically includes a live-fire exercise during which a decommissioned ship is sunk. Navajo towed several of these vessels on their final voyage, and has participated in other RIMPAC exercises as well.

RIMPAC 2006: Navajo towed ex-Belleau Wood from Pearl Harbor to be sunk.

RIMPAC 2008: Navajo towed ex-Horne from Suisun Bay, California to waters off Hawaii where she was sunk.

RIMPAC 2010: She towed ex-Monticello and ex-Anchorage from Pearl Harbor to where they were sunk.

RIMPAC 2012: She towed ex-Kilauea from San Francisco to Hawaiian waters where she was sunk. She also served as a dive platform for Royal Australian Navy divers.

RIMPAC 2014. Participated

RIMPAC 2016: Navajo towed ex-Thatch from Pearl Harbor to be sunk in the exercise.

Awards and honors
Navajo and her crew earned both the Navy Meritorious Unit Commendation and the U.S. Coast Guard Unit Commendation.

Deactivation
USNS Navajo was deactivated and stricken from the naval vessel register on 1 October 2016. After deactivation Navajo was moored at Pearl Harbor pending final disposition.