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. Neither ship still serve as SURTASS units.

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