Year Built
Official Number
National Steel and Shipbuilding
General Type
General Cargo
Specific Type
Break Bulk
Ship Length
528.50 feet
76.00 feet
Mast Height
Net Tons
7457.00 tons
Gross Tons
12716.00 tons
Cargo Capacity
Draft, Summer
Draft, Lightweight
Displacement, Summer
Displacement, Lightweight
Immersion, Summer
Immersion, Lightweight
Still in Govt. Service

Historical Narrative

The former naval oceanographic research ship H. H. Hess was originally built as the general cargo ship Canada Mail for the American Mail Line in 1965. The ship was constructed by the National Steel and Shipbuilding Company in San Diego, and launched on May 30, 1964. 

Canada Mail was the fifth of a series of vessels built to replace the line’s World War II-era tonnage.  It was placed into service in March 1965. American Mail Line operated between the Pacific Northwest and ports in Japan, Korea, Taiwan, Okinawa, the Philippines, Hong Kong, and Vietnam.  Cargoes bound for the East Asia were usually loaded in Vancouver, British Columbia; Seattle, Tacoma, and Longview, Washington; and Portland, Oregon. 

Canada Mail was built as the containerization revolution was still getting underway.  Aside from possible stowage on deck, no provision was made in its design for the transport of standardized cargo containers, and it remained a purely break-bulk cargo ship while in commercial service. 

In December 1973 the ship was briefly chartered by the Navy’s Military Sealift Command (MSC).  In 1974 it was “traded in” to the Maritime Administration and placed in the Reserve Fleet in Suisun Bay, California.  

Two years later Canada Mail was acquired by MSC for conversion to an oceanographic research ship.  The alterations were largely internal and below the waterline.  Outwardly, the vessel appeared little changed. 

The vessel was renamed the USNS H. H. Hess after a scientist in the field of oceanography, and designated T-AGS-38.  The ship’s new role was deep ocean research.  It was expected to stay at sea underway for as long as 34 days, charting the ocean’s topography and other features using multi-beam sonar.  

Much of this work was done in support of the Trident Fleet Ballistic Missile Submarine Program.  The Hess served the Navy for nearly 20 years. 

In 1992, Hess was removed from service and placed in the Suisun Bay Reserve Fleet.  The ship was declared non-retention in 1994. 

Vessel Name History

1965 - 1977: Canada Mail
1977 - 2011: H. H. Hess

Vessel Name History




No Mission for this vessel

Historical Documents
Name Download


Event Date Content
5/30/1964 Delivered by National Steel & Shipbuilding
4/5/1974 Entered Suisun Bay Reserve Fleet; MARAD acquired title as a trade-in vessel
Name Change
3/3/1977 Name changed from CANADA MAIL to H. H. HESS
3/3/1977 Transferred to US Navy for conversion to research vessel
9/1/2011 Vessel dismantlement complete

Ship Imagery

Status Cards


Date Type Name Download
(No Date) CALIFORNIA MAIL.pdf Default Generic Download Image
(No Date) CANADA MAIL.pdf Default Generic Download Image


No documents for this vessel

Shipwreck Information

No ship wreck information for this vessel