A towed array sonar is a system of hydrophones towed behind a submarine or a surface ship on a cable. Trailing the hydrophones behind the vessel, on a cable that can be kilometers long, keeps the array's sensors away from the ship's own noise sources, greatly improving its signal-to-noise ratio, and hence the effectiveness of detecting and tracking faint contacts, such as quiet, low noise-emitting submarine threats, or seismic signals.
The DUBV 43C towed array sonar of La Motte-Picquet (D 645).
When not deployed, an Akula's towed array is stored in a teardrop shaped container mounted on top of the vertical fin
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.
USNS Invincible as originally configured. Aft view of equipment for the Surveillance Towed-Array Sensor System (SURTASS), 1987.
USNS Able (T-AGOS-20) aft view of SURTASS equipment.