If the issue is "go to waypoint", you have that function.

In a rectangular search pattern, assuming no change in current or drift. You are using a rectangular pattern with a relativist "frame of reference". So your whole pattern is shifting relative to the center of search. If one is trying to simply track over an area in an orderly fashion then you can use a geostationary GPS pattern.

I think that thinking about the task at hand, trying to use your grey cells to search for the victim is a better approach. Having a chart plotter, track, MOB waypoint, wind instruments and a sipped log (to get a sense for current are all part of the package. An autopilot can free on up to think, look, listen, and search for the victim. But you need to use your head, head, eyes and ears.

This is, in anything but benign conditions scary stuff .

One of of my greatest heroes (and one of the best leader models) is Shackleton. http://books.google.com/books/about/Endurance.html?id=KpSULZB1efYC. His men knew he would come back for them. His management team would do everything possible to save them. If God forbid you are in water or in the boat, you have to do what you can to unite together and survive. Of course, sometimes people are lost and nothing can save them. But often enough you can rescue someone, especially if you ( and the victim) use you heads, your equipment, and make "lucky happen!

Of course there are many cases where it doesn't "work", so stay the muck on board!