USS North Dakota (SSN 784) was the first boat delivered with the results of that process, and USS John Warner (SSN 785) will be the second. Design for affordability led to a 20 percent redesign of the boat, primarily focused on the bow. The air-backed spherical array was replaced by a water-backed Large Aperture Bow (LAB) array. This change allowed the original design’s 12 single-purpose vertical launch system (VLS) missile tubes to be replaced with two large-diameter Virginia Payload Tubes (VPTs), each capable of launching six Tomahawk missiles utilizing the same Multiple All-Up-Round Canisters (MACs) currently used on the Navy’s four guided-missile submarines (SSGNs).
Replacing the 12 VLS tubes with two VPTs doubled the payload volume while dramatically reducing the amount of components and material associated with 12 individual tubes. Because the VPT provides the same diameter as an SSGN tube, the VPT benefits from potential payload commonality with the SSGN program.
The Virginia-class attack submarine USS New Mexico (SSN 779) surfaces through the arctic ice during Ice Exercise (ICEX) 2014. ICEX 2014 is a U.S. Navy exercise highlighting submarine capabilities in an arctic environment. U.S. Navy photo by Mass Communication Specialist 2nd Class Joshua Davies
Similarly, the new sonar array is much less complex to build and maintain than the old array and actually has improved capability.
“There were a number of other projects like that and, quite frankly, when you implemented a 20 percent redesign, you would expect that building the first boat of Block III, which was North Dakota, you would take a step back on the learning curve,” Hughes said. “But we were immediately able to see improvements in cost from what we had been building on the previous block.”
All of the Virginia-class boats through Block IV are the same length and same dimensions. The Block IV boats with VPT have the same number of missiles. Block V, with the VPM, will be longer. The Virginia class was specifically designed to accept the addition of modular mission hull sections during construction.
Reducing the construction time has many benefits.
“By having that shorter span, we can now install the latest combat system during construction, making these boats ready for mission-tasking immediately at delivery. We also reduced costs by 20 percent, and we’ve improved the quality of every subsequent ship,” said Capt. David Goggins, program manager for the Virginia-class submarine with Program Executive Office for Submarines (PEO SUB).
Sailors aboard Minnesota (SSN 783) operate their assigned consoles in the ship’s control in the forward compartment. Minnesota, along with other Virginia-class submarines, has three main levels and is divided into three sections: forward compartment, reactor compartment, and engine room. U.S. Navy photo by Lt. Timothy A. Hawkins
“Each Virginia-class submarine has higher quality and is a more complete ship at initial delivery. An independent government inspection and survey [INSURV] team comes on board before delivery to take the boat out to sea for three days and inspect all the systems. It’s really an independent assessment of the material readiness of our submarines. Each delivery has had a higher score than the previous,” Goggins said. “Our last delivery, 784 [North Dakota], had the highest INSURV scores yet.”