GAAAAAAAAAYYY!

It's not so much that the boat in the "safe lee bow" position goes faster. There are at least two benefits to being the boat in that position. First, and the reason most people cite, you're hitting that competitor just behind and windward of you with some really disturbed air. If this were the main benefit, it would be a great tactic in match racing but not in fleet racing. The next reason is the less obvious one, and the one that makes it worth doing in a fleet race. Without giving a lecture on aerodynamics, the boat in the lee bow position is getting benefit from the other boat. You may have heard that your head sail is in a lift relative to your mainsail, which is in a relative header. Well, when two boats are close like this, that concept is expanded. Because of the way air flow works the boat aft and windward causes the boat below and ahead to be sailing in a lift relative to all boats on the course not in a lee bow position. So if you lee bow someone, (1) you slow them down and (2) they give you a lift so you are sailing just a bit higher than other boats in the fleet. It may be brief and last only until the other boat tacks out (which she should do as soon as possible) but in a sailboat race, every little bit adds up! That said, it's still more important to sail your own race. If you would have tacked in about that spot anyhow, go ahead and lee bow someone. If, however, you feel it's a strategic benefit to keep going, then do that. Being on the best part of the playing field is more important than a small gain from a temporary lee bow.