SAN DIEGO — The Navy’s top acquisition official confirmed the service is canceling the over $700 million Surface Ship Torpedo Defense (SSTD) system due to poor performance in favor of other anti-torpedo technologies.

Earlier this month, the Pentagon’s head of weapons testing released its annual report

, which said in September 2018 “the Navy suspended its efforts to develop the SSTD system.”

The Navy's Surface Ship Torpedo Defense (SSTD) System. (Graphic: office of the Director of Test and Evaluation)
The Navy’s Surface Ship Torpedo Defense (SSTD) System. (Graphic: office of the Director of Test and Evaluation)

The Director of Operational Test and Evaluation (DOT&E) report said the Navy plans to restore all carriers to their normal configurations during maintenance availabilities from FY ’19-FY ’23.

Assistant Secretary of the Navy for Research, Development & Acquisition James Geurts told reporters Thursday “we are always looking at all of our portfolio to make sure what we had hoped to get out of it was actually delivering that on the waterfront or on the deck plates.”

“On that particular system when we took a look at it, versus its effectiveness and the cost, we made the decision that we weren’t going to continue to deploy that, we would pull that off the ships,”Geurts added.

Geurts underscored removing it from ships does not mean it was a waste or the technologies are not useful, “just the current instantiation wasn’t something we were going to keep on the ships.”

In place of the SSTD, the Navy intends to use other technologies to defend against torpedoes.

“It’s not that we are saying that protecting ships is less important, just that particular solution was not generating the value of the cost,” Geurts said.

The SSTD includes the torpedo warning system (TWS) to detect, localize, and alert incoming torpedo threats plus the countermeasure anti-torpedo (CAT) hard-kill countermeasure meant to intercept enemy torpedoes. Combined, these systems are called the anti-torpedo torpedo defense system (ATTDS).

Generally, the SSTD program was meant to provide an independent anti-torpedo protection for aircraft carriers, beyond relying on escort ships and friendly submarines. It was installed on three carriers by 2018 while two other carriers previously had temporary roll-on/roll-off versions.

However, the DOT&E report shows despite some incremental improvements and utility in 2018 the system was not improving fast enough.

The TWS had successfully alerted on inbound torpedoes in tests, and the CAT has demonstrated “some capability” to defeat an incoming torpedo.” However, DOT&E said “CAT has uncertain reliability. The lethality of CAT is untested.”

Reliability problems with test target surrogates, test equipment, and CAT hardware prevented the Navy from executing 2017 test scenarios in line with the contractor test plans or DOT&E approved test plans, the 2018 report said.

2018 testing then demonstrated contractors made progress towards operational requirements, but test data was “insufficient to assess operational effectiveness and operational suitability of TWS and CAT,” DOT&E said.

Overall, the weapons tester found that while TWS could successfully alert on inbound torpedoes “during simple and structured scenarios” further data was needed to assess the capability “within the envelope of relevant environments, operating profiles of the supported platforms, and employment tactics of threat torpedoes.”