By Rear Adm. Joseph Tofalo
Director, Undersea Warfare Division (N97)
Last Friday USS North Dakota (SSN 784) delivered to the fleet under budget and two days earlier than its contractual delivery date. As part of the Navy’s acceptance, North Dakota was evaluated in the areas of construction and equipment operation by the Board of Inspection and Survey (INSURV) team. The INSURV team assessed this as the best performance to date of any of the 11 Virginia-class submarines serving in the fleet. What makes this even more significant is the superior on time, and under budget performance that was accomplished, despite a 20% redesign of this, the first boat of the Block III Virginia-class submarines. The delivery marks a culmination of over five years of work by the Virginia-class Program Office, the shipbuilders, Supervisors of Shipbuilding, and the rest of the Navy team including a crew of more than 135 sailors who are training to operate forward in defense of our nation.
Carry a Big Stick
The arrival of North Dakota is a significant milestone and will improve our existing capabilities. The two newly designed Virginia Payload Tubes (VPTs), each capable of launching six missiles, replace the twelve individual missile tubes that comprised the Vertical Launch System (VLS) in previous submarines. Primarily done to reduce the cost of each submarine, moving from 12 individual cells to two larger diameter tubes has the added benefit of optimizing the equivalent space and providing additional future payload flexibility. In addition to weapons, we may also be able to leverage the efficient use of space in future submarines to deploy unmanned aerial or undersea vehicles for any variety of tasks. The flexibility gained is a significant force multiplier.
Another major, but less obvious war fighting improvement, is the shift from the traditional spherical array to a water backed Large Aperture Bow (LAB) array and advanced combat control system. The LAB array provides improved passive listening capabilities over traditional spherical arrays employed on earlier submarines. The LAB array includes a medium-frequency active array. The hydrophones used to determine a bearing of either incoming passive sounds or active reflected sounds are taken directly from previous design and technology advancements. The hydrophone advancements eliminate the need for Quality Assurance (QA) maintenance related specifically to submarine safety, and ultimately reduces costs. The redesigned bow was one of 100 design changes initiated as a part of the cost reduction strategy. The initiatives resulted in a savings of $100 million per hull. These savings, combined with improved performance, are a win by any standard.
The superior performance by North Dakota and the entire Virginia-class team, underpins the value the submarine force plays in a variety of missions from maintaining maritime trade routes through the full spectrum of conflict. Undersea dominance relies in no small part on this team delivering the best ships ready to support national objectives the day they are delivered. We are already working on leveraging technologies from North Dakota and the Virginia-class into the design of the nation’s replacement for the Ohio-class ballistic missile submarines. The Ohio Replacement is a national priority and we are recapitalizing our sea based strategic deterrent fleet with the same expertise and capabilities that delivered North Dakota.