Methods and related systems are disclosed. In an embodiment, a method includes determining a distance between a tow vessel and a predetermined point along a line being towed by the tow vessel. In addition, the method includes adjusting a length of the line from the tow vessel. Further, the method includes determining a change in the distance a predetermined amount of time after adjusting the length of the line. Still further, the method includes determining whether a difference between the change in the distance and the adjustment of the length exceeds a threshold value.