Surveillance Towed Array Sensor System

The AN/UQQ-2 Surveillance Towed Array Sensor System (SURTASS), colloquially referred to as the ship's "Tail", is a towed array sonar system of the United States Navy.

SURTASS Twin-Line consists of either the long passive SURTASS array or the Twin-line array consisting of two shorter passive arrays towed side by side. The Twin-line Engineering Development Model was installed on USNS Assertive, and the first production model was installed on USNS Bold. Both ships are no longer serving as SURTASS units.

As of 2009^[update], SURTASS was deployed on the four Victorious-class vessels and the USNS Impeccable (T-AGOS-23) (a small-waterplane-area twin hull (SWATH) vessel).

SURTASS began as development program in 1973 using the new research vessel Moana Wave. In 1980 SURTASS passed OPEVAL. The new Stalwart-class ocean surveillance ships had the first contract awarded on 26 September 1980 and were similar to the prototype ship, the Moana Wave. Initially the SURTASS system were passive, receive only sonar systems. The array was towed miles behind the ships and were designed for long range detection of submarines.

As the passive systems were being deployed, an active adjunct known as the SURTASS Low Frequency Active (LFA) systems was designed for long range detection. The active system must be used in conjunction with the passive received system. The active component transmits an audio signal between 100 Hz and 500 Hz from an array suspended below the ship while the passive SURTASS array is towed miles behind to receive the signal after it had reflected off the submarine. The active LFA system is an updated version of the fixed low frequency surveillance system known as Project Artemis. Although the Navy took steps to mitigate the environmental damage, environmental non-governmental organizations (NGOs) urged the Navy to prepare a public environmental impact statement. In 1996 the Navy published a notice of intent to prepare an environmental impact statement. The Navy has spent over $16 million on scientific research on the effects on marine mammals and mitigation systems as well as the development of an Environmental Impact Statement.

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