MV ''Cory Chouest'' is an ocean surveillance ship leased by the

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Department of Defense. It is the world's most powerful navy with the largest displacement, at 4.5 million tons in 2021. It has the world's largest aircraft ...

in 1989 and assigned to the Navy’s Special Missions Program. ''Cory Chouest'' had all SURTASS equipment removed and was returned to her original owners in 2008 completing nearly 20 years of service.

Construction

''Cory Chouest'' was acquired and modified by

Edison Chouest Offshore Edison Chouest Offshore (ECO), which started as Edison Chouest Boat Rentals in 1960, is a family of companies in the marine transportation business based in Cut Off, Louisiana. ECO owns and operates a fleet of platform supply vessels, Subsea Co ...

for use by the U.S. Navy as a modified TAGOS vessel. Originally used as a research platform in conjunction with the , the Cory was later modified to carry an active and passive sonar system. The vessel served until October 2008 when it went off charter.

Mission

The mission of ''Cory Chouest'' is to directly support the Navy by using both passive and active low frequency

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...

arrays to detect and track undersea threats.

Operational history

In January 1991, the ''Cory Chouest'' and ''Amy Chouest'' were used as part of the Heard Island feasibility test, an experiment to transmit low frequency sound through the ocean from

Heard Island The Territory of Heard Island and McDonald Islands (HIMI) is an Australian external territory comprising a volcanic group of mostly barren Antarctic islands, about two-thirds of the way from Madagascar to Antarctica. The group's overall land ...

in the

Southern Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it ...

as far as both ocean coasts of the US and Canada. The ''Cory Chouest'' was chosen because of its central

moon pool A moon pool is an equipment deployment and retrieval feature used by oil platforms, marine drilling platforms, drillships, diving support vessels, fishing vessels, oceanography, marine research and underwater exploration or research vessels, and ...

and because it was already equipped with an array of low frequency transmitters. A phase-modulated 57Hz signal was used. The experiment was successful and demonstrated that such sound waves could travel as far as the

antipodes In geography, the antipode () of any spot on Earth is the point on Earth's surface diametrically opposite to it. A pair of points ''antipodal'' () to each other are situated such that a straight line connecting the two would pass through Ea ...

. Planned transmissions had been for ten days, although owing to the bad weather conditions and the high failure rate of the transmitter elements, used at a frequency below their design frequency, the transmissions were terminated on the sixth day, when only two of the original ten transducers were still working.

Note

There is no journal entry on ''Cory Chouest'' at

DANFS The ''Dictionary of American Naval Fighting Ships'' (''DANFS'') is the official reference work for the basic facts about ships used by the United States Navy. When the writing project was developed the parameters for this series were designed to ...

References

External links

*
Special Mission Program

Military Sealift Command - Ship Inventory – MV Cory Chouest - Ocean Surveillance Ship
* Gordon D. Tyler, Jr.,″The Emergence of Low-Frequency Active Acoustics as a Critical Antisubmarine Warfare Technology", Johns Hopkins APL Technical Digest, Vol 13, No 1 (1992) p 145.

Ocean surveillance ships of the United States Navy 1974 ships {{US-mil-ship-stub