TR-1700-class submarine

The TR-1700 (Santa Cruz) is a class of diesel-electric patrol submarines built by Thyssen Nordseewerke for the Argentine Navy in the 1980s. These ships are the largest submarines built in Germany since World War II and are among the fastest diesel-electric submarines in the world.

Development
The original 1977 plan called for six ships, two TR-1700’s built in Germany by Thyssen Nordseewerke, two in Argentina by Astillero Domecq Garcia, and two smaller TR-1400’s also built in Argentina. The final agreement in 1982 was modified to six TR 1700’s.

Design
The submarine was designed by Thyssen and its features include high underwater speed, endurance, and survivability. The ship's four MTU diesel engines, four generators, and Siemens electric motor can propel it for speeds up to 25 kn. Eight 120 cell batteries are installed on the ships. They have a diving depth of 300 m.  Normal endurance of these ships is 30 days with an extended range up to 70 days. These ships are equipped to accept a Deep Submergence Rescue Vehicle (DSRV). Armaments include six bow 533-mm torpedo tubes and 22 SST (Special Surface Target) or Mark 37 torpedo. The automatic torpedo reload system can reload the tubes in 50 seconds.

The Argentine Navy requested that INVAP develop the CAREM nuclear reactor to power these submarines, but the program was halted in late 1980s.

Thyssen proposed the TR1700A for the Collins-class submarine program. The proposed design had an reworked pressure hull, was six meters longer, and half a meter wider than the TR1700's for Argentina. It lost to the Type 471 from Kockums, an enlarged Västergötland-class submarine.

Service
The first two submarines were delivered on schedule in 1984-85. The remaining four built in Argentina were suspended due to the Argentinean economic crisis of the 1980s. In 1996 work completely ceased on ARA Santa Fe at 70 percent (or 52 percent) completion while ARA Santiago del Estero was only 30 percent complete. After attempts to complete and sell the ships to other countries (Taiwan) failed they were cannibalized, along with the parts for the fifth and sixth units, to support the continued operations of the first two submarines.

The Santa Cruz received its mid-life modernization at Arsenal de Marinha, Rio de Janeiro Brazil between September 1999 and 2001. The work involved the replacement of the engines, batteries, and sonar. Her sister ship San Juan entered Astillero Domecq Garcia shipyard to receive her refit in 2007 and will receive similar work.

In September 2010 it was revealed that the Ministry of Defense is conducting feasibility studies to decide if ARA Santa Fe (S-43) should be completed. The decision should be made sometime after completing the mid-life modernization of ARA San Juan (S-42). The feasibility study includes technicians from INVAP and CNEA, who are investigating the possible use of a CAREM reactor in the unfinished vessel. The estimated cost of completing Santa Fe is $60 million.