Having that kind of tracking for other ships is actually something I remember from twenty years ago or so: it was called AIS, and you could use it to very easily tell if you were going to get close to another ship with it; pretty much all the big ships had it at the time. It was particularly nice because it would tell you the name of The ship, which made it a lot more likely that you could raise them in the radio.

One interesting note is that steering will actually change when you lost engine power even if the rudder remains in place (which I believe it does) because the propellers are no longer driving the water across the rudder, which lessens its effect..

The effects of wind and current are another factor to consider, especially closer to shore. I'm sure it's possible to model the course of a vessel, but it's a big and constantly changing problem.