The Navy accepted delivery of the eighth and last Block III Virginia-class submarine, the future USS Delaware (SSN-791), on Oct. 25.

Construction on SSN-791 started in 2013 and it is set to be commissioned in April 2020.

The Virginia-class submarine future USS Delaware (SSN-791) at sea for sea trials in the Atlantic Ocean on Aug, 31, 2019. (Photo: U.S. Navy)
The Virginia-class submarine future USS Delaware (SSN-791) at sea for sea trials in the Atlantic Ocean on Aug, 31, 2019. (Photo: U.S. Navy)

As a Block III vessel, SSN-791 will feature a redesigned bow that replaces 12 individual vertical launch tubes with two large-diameter Viginia Payload Tubes that can launch six Tomahawk missiles each as well as a water-backed large-aperture bow sonar array in place of a traditional air-backed spherical array.

The Navy said the Block III changes “reduced the submarines’ acquisition cost while maintaining their outstanding warfighting capabilities.”

In August, shipbuilder Huntington Ingalls Industries’ [HII] Newport News Shipbuilding conducted initial sea trials with the vessel, which spent three days at sea proving its systems, components, and compartments in the final phase of construction. The earlier sea trials also submerged the vessel for the first time and performed high-speed maneuvers (Defense Daily, Sept. 3).

In a February earnings call, HII president and CEO Mike Petters admitted income was down, partly due to a drop in NNS from lower performance in the Virginia program that caused higher costs for the company. That was specifically because SSN-791 has higher costs than expected as the last Block III vessel and due to work on the first submarine in Block IV, the future USS Montana (SSN-794) (Defense Daily, Sept. 3).

The contract for the Delaware was awarded in late 2008 and, according to the Navy’s FY 2019 budget request documents, the Delaware was planned to be delivered this past February. However, in the Navy’s FY 2020 documents, that date was pushed back to June. With this delivery, HII missed that target by almost five more months.

The FY 2020 documents planned for the post-shakedown availability (PSA) to start in October, finishing in January 2020,  the formal end of the post-delivery period.

HII said the cost and schedule delays associated with SSN-791 have not diminished its quality.

“Like the last two submarines we delivered to the Navy, Delaware has received some of the highest quality scores since the Virginia-class program began. Our team of shipbuilders continues to perform at a high level, and nothing makes us prouder than delivering one of the most mission-ready submarines to the fleet,” Dave Bolcar, Newport News’ vice president of submarine construction, said in a statement.

The Navy expects to commission SSN-791 in 2020.