AN/SQS-23 Sonar

The Anti-Submarine Warfare System provides search, detection and tracking capabilities for surface and sub-surface craft. Skilled operators can classify target vessels from the audio and visual echoes. With a low frequency sonar system, the DDG searches for hostile underwater targets and cuts them through to its Combat System for engagement by its ASW weapon system - the Mk32 Torpedo Tubes. The AN/SQS-23 was a long range, azimuth-scanning type of search and attack sonar used for search, search-analyze, attack-RDT, attack-SDT and hand-key applications. Installed in DDG-2 and DDG-16 class ships, it used the Ship center display (SCD) for search operations and target center display (TCD) for attack.

The SQS-23, first deployed in 1958 and operating at 5 kHz, required a transducer more than 20 feet in diameter. The expected payoff for such an enormous array was direct path detection ranges of more than 10,000 yards and the first use of bottom bounce propagation for detection beyond the direct path.

The SQS-23 encountered serious problems during its first decade in operational use and was never able to reliably achieve bottom bounce detection ranges, though it did extend direct path ranges out to the point where the destroyer once again became weapon limited rather than sensor limited in a tactical engagement against a submerged diesel on battery.

The SQS-23 was also too large to be fitted to all but the largest fleet destroyers of World War II, and the anticipated follow on to the SQS-23, the 3.5 kHz SQS-26, made matters even worse with an even larger transducer and greater power requirements. This demonstrated that new construction was going to be necessary to create an adequate surface ASW platform, but that even if designed as austere, ASW-only Frigates they would be larger and much more expensive than the largest World War II DD. Indeed, starting in 1960, 58 SQS-26 ships were authorized of the Bronstein (2), Garcia (10), and Knox (46) classes, but the SQS-26 also experienced problems similar to the SQS-23 and was not fully accepted for service use by the Navy until 1968.

Even limited to the direct path detection ranges of the SQS-23, the destroyer community also had trouble developing weapons and fire control systems that could track and attack high speed contacts at the ranges that SQS-23 detected them.