[thyristan]

Only very small motor boats are agile enough that you can turn on a dime and not loose sight of a man-over-board. And even then, it strongly depends on wind, current and boat speed. Also, orientation on the seas, sense of direction and getting to a remembered position again is very very hard to impossible. Especially when agitated. You might try using compass and GPS, but those are imprecise, overwhelming and useless when there is any kind of waves or current.

It is absolutely vital to keep the man-over-board in sight. Practically no exceptions.