Not necessarily the contact could be heading in any direction you will always hear the noisy screws in the water which are in the stern end of the vessel.What I meant is that the bearing will be more towards the stern end of the vessel while if you where to look with the scope the COT will be a few degrees to one side or the other depending on the contacts direction of travel.

At some point no matter the contacts direction of travel it will be at 0 degrees if it passes directly in front of your bow the possible tracks are numerous.

That is why you have to track a contact for a few minutes in order to ascertain the direction of travel.And why sound only attacks are so tricky.