new guy

[Pisces]

Originally Posted by Perfect Midnight

...
and how can i tell if a ship is moving twords me or away with the hydrophones.

If it is comming very sharply towards you then you only hear the sound getting louder. Until the very last moment when it zips by your side and moves away. Assuming it wasn't a DD that noticed you.

If it is on a course less directly toward you then the change in sound bearing is slowly increasing speed. At first it might take 10 minutes to move 1 degree (or even more), then 9, then 8, then 7, and so on an so on until the change has a maximum drift speed. That is when the AOB is close to 90. Beyond that the target is moving away from you and the drift of the bearing slows down again. To very slow at the horizon.

Compare this with being at a rail-crossing. When the train is in the distance it doesn't seem to move. But when it is passing you it is going sideways very quickly. So, as it got closer your head/eyes view on the train must have accellerated in turning. Then, when it is long past you, far away, it again seems to hardly move sideways. So your head/eyes movement has slowed down again.

This even happens when you are moving quickly on the surface when you are sprinting ahead (as opposed to sitting still, or moving slowly submerged). If the bearing drift is speeding up, then range is decreasing. Be carefull of detection. If the bearing speed is slowing down, then range is increasing. You'll loose him out of sight eventually.