Well once again I'm sure I will be pointed out as wrong but here goes, in the example of the boat. My understanding is that if you intend to go to point B from point A and there is a current and you want to make a single heading change to accomplish this then you are going to have to overshoot your target to allow for current drift. Thus the path traveled is going to be an arc. Again this is not guessing nor what I have read in a book. This is first hand experience spending many hours piloting a 18.5 ft boat in the SF Bay and connected bays and sloughs. Piloting an object in any fluid would be the same.

This brings up another question, just how much rudder are you guys in visioning me holding in a cross wind?

Final thought on this post. You guys want to come here bashing Sensi and myself for chest bumping and such but you are the guys in a beginners forum posting complicated vector formulas and such that are clearly going to be over the head of 99% of beginners heads just because your ego won't allow you put yourself in the shoes of an R/C pilot with 35 years hands on experience. Think about that will ya.