Positioning a conventional towfish is a challenge in deep water.

Figure 1 shows a typical deep tow survey scenario — a tow vessel with a deep towed sonar is followed by a chase boat, which positions the towfish. Tow cable is deployed. Towfish positions are radioed to the towboat by the chase boat as the towboat attempts to steer the towfish along a prescribed survey line.

As shown in Figure 2, if an AUV is used instead of a deep towed sonar, the project is simplified. Only one vessel is required. That one vessel, the AUV mother ship, transits directly over the AUV, just like the chase boat tracks over the towfish.