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Latest US Nuclear-Powered Attack Submarine Completes Initial Sea Trials

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Latest US Nuclear-Powered Attack Submarine Completes Initial Sea Trials

The future USS Indiana completed alpha trials ahead of its planned handover to the US Navy.

Latest US Nuclear-Powered Attack Submarine Completes Initial Sea Trials
Credit: U.S. Navy

The latest Virginia-class nuclear-powered fast attack submarine (SSN), the future USS Indiana (SSN 789), has successfully completed its initial set of sea trials, Huntington Ingalls Industries’ Newport News Shipbuilding division said in a May 25 press release.

“The initial round of sea trials, known as alpha trials, provides an opportunity to test all systems and components,” the company said.  The trials, conducted off the Virginia coast, included submerging for the first time and high-speed maneuvers while on the surface and submerged (see a video of the sea trials here).

“Sea trials is a significant milestone and the first major test of submarine’s capabilities at sea,” said Dave Bolcar, Newport News’ vice president of submarine construction. “We are pleased with how Indiana performed and look forward to continuing our testing program before we deliver the boat to the U.S. Navy later this year.”

Construction of the Indiana kicked off in 2012. The boat was christened in April 2017 and launched in June of the same year. It is the 16th Virginia-class SSN built overall, and the sixth Block III submarine — Virginia-class SSNs are built in block increments, with Block I and Block II already delivered to the U.S. Navy.

Redesigned Virginia-class Block III SSNs are equipped with the so-called Virginia Payload Modules (VPM) – larger tubes that increase the ship’s missile-firing payload possibilities (See: “US Subs Getting Fire Power Boost”). As I explained elsewhere:

While the first 10 Block I and Block II Virginia-class submarines feature 12 individual 21-inch diameter vertical launch tubes able to fire Tomahawk Land Attack Missiles (TLAMS), “the Block III submarines are built with two-larger 87-inch diameter tubes able to house six TLAMS each,” according to the U.S. Navy website. The new 87-inch tubes have been designed to accommodate future missile systems in addition to the Tomahawk.

In addition, Virginia-class Block III boats are equipped with four torpedo tubes for MK48 torpedoes. Furthermore, next to a redesigned bow, Block III Virginia-class boats also contain “a water-backed Large Aperture Bow (…)  sonar array that replaces the air-backed sonar sphere found in the first 10 Virginias.” This, in combination with the its so-called fly-by-wire capability, enables the boat to perform important intelligence and surveillance missions.

Virginia-class SSNs are multipurpose platforms designed to seek and destroy enemy submarines and surface ships as well as conduct land strike missions with Tomahawk cruise missiles. Additionally, the subs can used for the “delivery of special operations forces (…) irregular warfare; intelligence, surveillance and reconnaissance; and mine warfare,” as I explained elsewhere.

The Indiana is expected to be commissioned in June 2018. The last Virginia-class submarine, the USS Colorado (SSN-788), the 15th boat of the Virginia-class, was commissioned in March of this year.