USNS Mizar (MA-48/T-AGOR-11/T-AK-272) was a vessel of the United States Navy. She was named after the star Mizar.

Cargo ship

Mizar was built as a small ice-strengthened, double hull, cargo ship of the Eltanin class on a Maritime Administration type (C1-ME2-13a) hull, by Avondale Marine Ways, Inc. from January 1957. She entered service on March 7, 1958, and served as part of the Military Sea Transportation Service (MSTS), working around Canada and Greenland, with a single voyage to Antarctica in 1961.

The loss of the on April 10, 1963, and problems handling heavy search equipment over the side from in 1963 drove the Naval Research Laboratory (NRL) requirement for a larger, more capable ship than the usual oceanographic research type. A search for a candidate ship, capable of being modified for an inboard center well, led to selection of Mizar in late 1963.

Acoustic navigation system

The only means of subsurface navigation locating a search vehicle or other sensors relative to the ship and bottom is by acoustic navigation. Towed deep vehicles may be half a mile from the towing ship and respond to the ship's movements as much as half an hour after that movement. A capability developed at the University of Washington Applied Physics Laboratory was implemented for Mizar. The system, an early implementation of a short baseline acoustic system, is composed of a triangular array of hydrophones on the ship's hull, a transponder on the towed vehicle with an acoustic pulse triggered by a signal over the towing cable, and a sea floor transponder triggered by an acoustic signal from the ship. By using travel times of the signals distances can be computed. A response from the vehicle can be computed for relative position with regard to the ship and that from the bottom transponder is used to find its relative position. The towed vehicles relative position to the ship and bottom is then computed.

Research

The ship was fitted to perform extensively in ocean science and technology with acoustics an important specialty. Mizar supported scientists from three NRL divisions. The Acoustics Division supported undersea surveillance, fleet sonar systems and studied undersea sound propagation. The Ocean Sciences Division worked in the classical oceanography fields of chemical, physical and biological oceanography and atmospheric studies. Research and development regarding materials and ocean engineering and the ship's searches were under the Ocean Technology Division.

As an example of extensive acoustic research with general oceanographic observations included was the ship's work in Operation NORLANT, an acoustic propagation and noise experiment that involved aircraft as well as NRL ships Mizar and and the Norwegian research vessel Sverdrup in the Greenland, Norwegian and Barents seas. In one instance Mizar penetrated the ice pack while Hayes remained in the open sea. The closure of the ice and mechanical problems led to Mizar becoming stuck in the ice pack along with her icebreaker escort which also suffered from mechanical problems. Both were freed by after some days.

One of the NRL developments deployed on Mizar was the Light Behind Camera (LIBEC) that extended the coverage of deep sea cameras significantly. That system was used to photograph portions of the Mid-Atlantic Ridge during Project FAMOUS.

Searches

Often more public attention was drawn to the ship's searches for sunken ships than to routine research.

250px|thumb|right|Mizar's deep towed vehicle.

250px|thumb|right|Overhead view of Thresher's upper rudder photographed from Mizar's deep towed vehicle.

  • Mizar took part in the search operations for Thresher, the Palomares Incident in which nuclear weapons were lost off Palomares, Spain.
  • The ship was engaged in the extended search for , which was found in October, 1968.
  • She also took part in searches for foreign wrecks, including Eurydice.
  • In 1969 Mizar was called on to locate the Woods Hole Oceanographic Institute deep submersible Alvin, which had sunk in . Mizar lifted the submersible to shallow water.
  • Mizar was not involved, despite speculation, in the search for the Soviet submarines K-129 as the ship was well known to the Soviets and could not operate clandestinely.

Addition of water sampling capability to the search vehicle allowed environmental monitoring as well as location and photography. One example is the ship's monitoring of the scuttled, nerve agent laden, five times between 1970 and 1974. The entire hulk could be photographed and water samples taken close to its deck.

Assignment to undersea surveillance

The Naval Research Laboratory was forced by increasing ship costs to choose between Mizar and the newer Hayes and chose to retain Hayes. In 1975 Mizar came under the technical control of the Naval Electronic Systems Command (NAVELEX) to become part of the "Caesar fleet" supporting the Sound Surveillance System (SOSUS) installation under the unclassified name Project Caesar. A footnote to a table of ships in The Federal Ocean Program dated April 1974 noted that Mizar was funded and operated by NAVELEX and no longer was funded as an oceanographic ship.

The ship was assigned to Military Sealift Command Pacific in 1975 and underwent another major modification in 1980. As of 1979 Mizar was the most recently built ship of the five ships directly assigned to Project Caesar.

Disposal

Mizar was withdrawn from active service entering the James River National Defense Reserve Fleet on December 17, 1989. The ship was withdrawn October 24, 1991 for stripping before returning December 18 awaiting disposal. Bay Bridge Enterprises, LLC of Chesapeake, Virginia was awarded a $243,900 contract for the dismantling and recycling of Mizar on 21 July 2005.

Footnotes

References

Bibliography

  • AGOR Numeric List
  • USNS Mizar (T-AGOR 11)
  • Side view of the towed sled used by the Navy research ship Mizar in the search for the nuclear submarine USS Scorpion (SSN-589).