Sailors On U.S. Navy Carriers Are Still Training To Use Unreliable Anti-Torpedo Torpedoes

The Navy plans to rip these systems out of five Nimitz class carriers, but until then, the service wants its crews trained on how to use them.

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Sailors on board some of the U.S. Navy's Nimitz class aircraft carriers are still training to employ an unreliable anti-torpedo defense system nearly a year after it stopped work on the program entirely. The service still plans to remove these defensive systems from the ships completely within the next four years, but until that happens, personnel will have to remain qualified to use them, if necessary.

The Navy recently posted images online of sailors on the USS Dwight D. Eisenhower training on the Anti-Torpedo Torpedo Defense Systems (ATTDS) as part of a routine Board of Inspection and Survey, or INSURV, in July and August 2019. Congress has mandated that all Navy ships must pass an INSURV certifying their mission readiness at least once every 60 months. INSURVs are multi-phase processes that offer opportunities for ships' crews to identify and correct deficiencies. Eisenhower's crew would have had to demonstrate proficiency with all of the ship's systems, including the ATTDS.

"The Navy is planning to remove ATTDS from aircraft carriers incrementally through fiscal year 2023 as the ships cycle through shipyard periods," William Couch, a spokesperson for Naval Sea Systems Command (NAVSEA), confirmed to The War Zone in an Email. "At present, the Navy is sustaining the ATTDS systems that are still installed on some vessels, where it is necessary for the Sailors to train with the system to maintain their qualifications in preparation for future deployments."

The pictures the Navy released show sailors aboard Eisenhower loading a training version of the Countermeasure Anti-Torpedo (CAT) into an ATTDS launcher and then firing it on July 31, 2019. For unexplained reasons, the service subsequently removed an image of the actual CAT launch, seen at the top of this story, from the official Defense Visual Information Distribution Services (DVIDS) website, though versions are still available elsewhere

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Sailors onboard the Nimitz class aircraft carrier USS Dwight D. Eisenhower load a training version of a Countermeasure Anti-Torpedo (CAT) onto a launcher on July 31, 2019.

The CAT is essentially a miniature torpedo that is six and three-quarters inches in diameter and approximately 85 inches long. It can either function in a hit-to-kill mode, destroying incoming torpedos by physically slamming into them, or with a glancing blow by using its small warhead. The Navy has also been exploring turning this interceptor into a small offensive weapon, called the Compact Very Lightweight Torpedo (CVLWT). You can read more about both CAT and the CVLWT in detail this past War Zone feature.

The complete ATTDS also includes a Torpedo Warning System (TWS), which is towed sonar array that the carrier pulls behind it, and a centralized control system. As of the end of 2018, five Nimitz class carriers, including Eisenhower had the system installed. The other carriers equipped with the anti-torpedo torpedo defenses were USS George H.W. Bush, USS Harry S. Truman, USS Nimitz, and USS Theodore Roosevelt. It is unclear how many of these ships still have the system installed.

Additional images from Eisenhower's INSURV showed an MH-60S Sea Hawk helicopter from Eisenhower recovering a CAT training round using a specialized basket slung underneath after another launch on Aug. 11, 2019. The training round does not have a live warhead and deploys a bright red-orange airbag after traveling a certain distance that brings it to the surface for recovery.

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An MH-60S Sea Hawk scoops up a training version of the CAT after a launch on Aug. 11, 2019. You can see its red-orange airbag floating on the surface.

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The MH-60S flies the CAT training round back to Eisenhower.

It makes perfect sense, in principle, that the Navy would want crews on any of its ships to be fully qualified to use all of the equipment on board. The issue here, of course, is that the ATTDS, by the service's own admission, is so unreliable it isn't worth keeping on the carriers. 

By the time the Navy stopped work on the program in September 2018, the TWS had only shown "some capability" to spot incoming threats at all and was still suffering from high instances of "false positives," that is to say, mistakenly thinking it had detected an enemy torpedo, according to a regular report from the Pentagon's Office of the Director of Operational Test and Evaluation. That same review said that the "lethality of CAT is untested" and that these interceptors had "uncertain reliability."

In short, at best, the two key components of the ATTDS had demonstrated that they might work, in principle. You can read more about the known issues with the system in greater depth in this previous War Zone story.

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A diagram showing how the ATTDS is supposed to work in principle.

It's not clear how much of a capability the ATTDS in its present form would actually offer, even in an emergency, especially given that the Navy is no longer working to improve its functionality, at least publicly. Given known reports about its reliability, or lack thereof, a ship's crew might be reticent to even try to employ it in an actual combat scenario.

We also don't know how much time and effort sailors spend on maintaining qualifications on the ATTDS. Still, that they are doing so at all comes at a time when the Navy has been seriously reviewing the time the crews of its ships spend on various tasks, as well as sleeping, amid concerns about overworking personnel and increasing the risks of accidents as a result. The service began looking into these issues after a pair of fatal collisions involving Arleigh Burke class destroyers in the Pacific in 2017. Subsequent investigations found that a lack of sleep, as well as lax training standards and other factors, contributed to those accidents.

At the same time, some anti-torpedo torpedo capability may be better than none, especially in the face of the very real threat posed by increasingly advanced and ever quieter submarines armed with steadily improving torpedoes in service with the navies of potential opponents, such as Russia and China. These countries both have submarines armed with torpedoes that home in on a ship's wake, making them largely immune to acoustic countermeasures, and that have other features that make them difficult to detect and evade.

However, this doesn't seem to have changed the Navy's overall opinion of ATTDS, at least in its current guise. But until the service rips the last of these systems out of its Nimitz class carriers, because they technically remain an operational system on those ships, it looks like sailors will continue to spend at least some time training to use them, even if they don't really work.

Contact the author: joe@thedrive.com