Most methods to estimate the position of a submerged asset rely on measuring the two-way travel time of an acoustic signal to and from a transponder mounted on that asset. Some alternative methods use one-way travel times and synchronized clocks, and others use multiple direction-only measurements from different locations. The method presented here estimates the location of a submerged asset using a single one-way acoustic ping, without synchronized clocks. The tracker must be able to estimate the direction of the incoming acoustic signal, and the submerged asset must be able to encode its own depth in the transmission. Simple trigonometry then gives the location of the submerged asset relative to the tracker.