Side scan sonar (SSS) is a side-imaging sonar mounted in a torpedo-like sonar fish towed above the bottom. The sonar fish emits ultrasonic rays that are reflected back from the seabed and objects. The time and strength of the sound echo is analyzed and then converted into a digital image.
Sonar surveys is particularly effective for the detection and positioning of objects such as wrecks, mines, pipes, or other objects and can also be used to assess the hardness and nature of the seabed. Large areas can be quickly searched as the sonar can see up to 150m to each side and be towed at several knots speed.