That's exactly what you call it, i.e. stern overhang.
We could get into a big argument here about how "overhangs extend the waterline" when the boat heels. It does to some degree but the question is is that added length doing any "work" or isit just being dragged along. I'm sure we will hear from a lot of experts on the subject.
The simple answer is this: Look how much of that stern is out of the water
. And in this case the camera
angle is actually doing the boat a favor. Just dangling overhang along in either the bow or the stern does nothing to increase the sailing length of a boat. You have to immerse volume in order for the boat to gain speed in a heeled state.
Now I will put on the other hat. Some AC studies have shown that ovehangs can make a boat faster in a chop.
You see what you want to see. Nice boat isn't it?