The long range AN/SQS-26 sonar, installed on FF-1052 and FFG-1 class ships, is designed to use direct, bottom reflected and convergence zone acoustic propagation paths where they occur in the oceans to achieve maximum effectiveness. Active modes include bottom bounce, bottom bounce track, bottom bounce triple frequency, convergence zone, omni-directional. Passive modes include audio via headphone, video via plan position indicator (PPI), B-scope, A-scan recorder, graphic indicator, sector scan indicator, azimuth recorder, and numerous dial indicators.
The SQS-23 was too large to be fitted to all but the largest fleet destroyers of World War II, and the 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.
The eventual success of the SQS-26 get well program led the surface community to finally abandon DASH in 1968 and embrace a manned helicopter option. This led to the LAMPS I program, a conversion of a lightweight, commercial utility helicopter, which first deployed in 1972. LAMPS I was small enough to operate from many DASH ships and it gave SQS-26 ships a reliable, first convergence zone weapon. LAMPS finally gave surface ships a final location and detection system to go with its convergence zone sonar so they could finally use SQS-26 and towed arrays.
The LAMPS/SQS-26 combination was widely deployed in the Bronstein, Garcia, and Knox class destroyer escorts (later retyped as FFs-1037-1098), 58 of which were deployed between 1960-1967. These were arguably the first truly successful, postwar ASW ships, and at the same time, certainly the least popular members of the destroyer community. This inverse relationship between ASW effectiveness and acceptance in the destroyer community highlights the fundamental doctrinal turmoil that community was experiencing during this period.
The surface force slowly evolved from a sensor/weapon suite based on the SQS-26, ASROC, and LAMPS I to one that included by the mid 1980s a passive towed array and the longer range LAMPS III. The LAMPS/towed array combination revolutionized surface ship ASW capabilities by combining the detection ranges heretofore only achieved at the tactical level by submarines deploying large, below layer, passive arrays with the rapid, long range prosecution capabilities provided only by air ASW assets.