Key point: Overall, aside with the fact that the Navy simply needs more submarines to make up for a severe shortage in undersea assets, America’s silent service is in good condition from a technological standpoint.

The United States Navy might defer developing a new next-generation SSN(X) unless such a design holds the potential to provide a revolutionary leap over a modernized variant of the current Virginia-class attack submarine (SSN).

(This first appeared in late 2016.)

While the Virginia-class was developed in the 1990s to be a cheaper alternative to the much more capable and expensive Seawolf-class (SSN-21-class), the SSN-774-class was designed to be as stealthy and to have greater multi-mission capabilities than its larger counterpart. Over the years, the Virginia-class has proven to be an adaptable and versatile design with plenty of room for growth. Indeed, the Virginia-class submarine—or VCS as many senior U.S. Navy officials call it—may prove so capable that a future SSN(X)—which is tentatively planned for 2034—might prove to be unnecessary.

“When is the transition from Virginia-class submarine to SSN(X)? And it’s currently scheduled for about 2034.” Naval Sea Systems Command’s program executive officer for submarines Rear Adm. Michael Jabaley told The National Interest during a Sept. 16 interview in his office. “So we have Blocks V, VI and VII on the Virginia and at some point in the future, we’ll have to sit down and make that decision. And the decision will be: Ok, has our science and technology and research and development work to date shown there is enough there to warrant designing a new submarine and starting to built it at that point or should we move that point—most probably out to the right—and keep building Virginia because with Block VIII we can insert the most promising technologies and make it still be the best submarine out there and perhaps wait for some phenomenal technological development to come to fruition.”

The Navy will have to make the decision on developing a new SSN(X) with potentially game-changing technologies or continue building advanced Virginia-class variants roughly seven or eight years from now, Jabaley said. Though Jabaley didn’t address what kinds of “phenomenal technological developments” it might take to justify developing a future SSN(X), during his earlier testimony before the House Armed Services Committee (HASC) in July, he suggested that a future SSN might act as an underwater mothership for unmanned underwater vehicles.

Moreover, in order to drastically improve acoustical performance, a next-generation submarine would need to dispense with moving parts. “At some point we’re going to have to move beyond a rotating mechanical device to push the ship through the water,” Jabaley told the HASC. “Although we’re not there yet on the oceans being transparent, one of the biggest things that causes noise to be radiated into the water is the rotating machinery and the propulsor itself moving through the water and exciting various parts of the stern and the submarine to radiate noise.”

The Navy has essentially reached the limits of what is possible for acoustic signature reduction with a purely mechanical system. While the future Ohio Replacement Program ballistic missile submarines (SSBN) are expected to use a permanent magnetic motor to increase stealth, Jabaley wants to take a step further. “The field of biomimetics is very interesting to me when you look at nature in action and you think: ‘Boy, it would be great if we could design something that would take that leap forward and get us into a realm that would be acoustic-self unlike anything we’ve ever done before,’” Jabaley said told the Congress.

In the nearer term, some of the advanced technologies that could be incorporated into a future Virginia-class derivative could include a version of the permanent magnet motor that is slated for the Ohio Replacement Program SSBNs. But most of the refinements to the Virginia-class are likely to be more modest. The service is already gearing up to test prototypes of some acoustical modifications the Navy hopes will keep the VCS ahead of the competition onboard a new Virginia-class boat that will be delivered late next year. While Jabaley has spoken about some of the details publicly before, he requested that The National Interest not further publicize the specifics about that effort.

In general, Jabaley said that the new modifications are the first major improvements to the Virginia-class’s acoustical performance since SSN-774 became operational in 2004. The Navy was spurred into action by the advent of Russia’s new Project 885 Yasen-class SSGNs, the first of which—called Severodvinsk—has greatly impressed the service’s leadership.

“We’re continually developing new technologies and new combat capability to ensure our submarines maintain our significant advantage in the undersea domain,” Jabaley said. “That includes the stealth of our submarines, that includes sensor performance—in terms of sonar arrays—and that includes our significant advantage in combat system electronics—the processing and the basically computer algorithms that aid the crew in solving the tactical situation. And we are developing technologies that are being prototyped and will be included in future Virginia-class submarines, are being evaluated for inclusion on Ohio Replacement submarines, are being evaluated for inclusion for backfit on the Virginia and even the Ohio-class SSBNs. That includes advances in sonar, in quieting, and in combat capability.”

Incremental improvements have been an integral part of the Virginia-class program from the outset. Every new Block of Virginia-class boats has improved on the previous one. Indeed, after the first two Virginia-class submarines were delivered, Jabaley pointed out that the program rapidly improved its performance and delivered boats months ahead of schedule while reducing costs. Even the first Block III boat—USS North Dakota (SSN-784)—which included a twenty percent redesign of the entire submarine to facilitate the inclusion of a new water-backed Large Aperture Bow (LAB) array sonar and two large payload tubes to replace a dozen individual cruise missile tubes—came in ahead of schedule. “And we expect to continue to deliver below contract,” Jabaley said. Indeed, that’s while increasing performance—the LAB offers improved capability over the original air-backed spherical bow array, added Capt. Michael Stevens, the Navy’s Virginia-class program manager, who was present during the interview with Jabaley.

The Block IV Virginia-class submarines—the first of which are currently in the initial stages of construction—focus on reliability and maintenance improvements, Jabaley said. Indeed, because they will require far less time in dry dock, the boats will be available for extra deployments (an SSN normally deploys 14 times during its 33-year lifespan)—which will help the Navy with its mission to maintain a global submarine presence. “Once you wrap all of those changes into the ship’s maintenance plan, it allowed us, starting with the Block IV submarines, to reduce four depot level maintenance periods down to three and increase the deployments from 14 to up to 15,” Jabaley said.

However, the biggest improvement to the Virginia-class will come with the Block V vessels—the first of which will start construction in 2019 as the second submarine (SSN-803) built that year. The Block V submarines will add a Virginia Payload Module (VPM) that will add four additional payload tubes amidship, each of which can accommodate seven Tomahawk cruise missiles for a total of 28 weapons. Overall, the Block V Virginia-class will be capable of launching 40 Tomahawk cruise missiles from its payload tubes.

“The Navy’s program of record [which will likely be increased] includes Virginia Payload Module on every Virginia-class submarine beyond that,” Jabaley said. “So that make 19 submarines with VPM—makes 20 if we add that second submarine in 2021—and that act of adding the VPM to those 19 submarines provides a significant mitigation for the loss of the [four Ohio-class boomers, which were converted into] SSGNs. It’s not exactly 100 percent, but it absolutely mitigates the fact that Ohio, Michigan, Florida and Georgia decommission in the mid-20s.”

Overall, aside with the fact that the Navy simply needs more submarines to make up for a severe shortage in undersea assets, America’s silent service is in good condition from a technological standpoint. The challenge will be to convince Congress to add funding to increase the build rate to counter a resurgent Russian and growing Chinese submarine force.

Dave Majumdar is the defense editor of The National Interest. You can follow him on Twitter @DaveMajumdar.