This one is a little tricky to ask without diagrams, I'll do my best...

Scenario:
Let's say you're sailing straight ahead (12 o'clock) position, wind coming from 3 o'clock at say 15knots, happy days. When your board speed reaches 15knots, now combined (apparent?) wind direction is from 1:30, and greater than 15knots.

Questions:
1. Based on the assumption above, faster you go, apparent wind direction gets closer to head on (12:00). So faster you go the more you'll need to sheet in, right?
2. Wind from 1:30 is about the limit of my setup. Past this the wind just becomes too much head on, and hence slower. So, faster you go, do you change course towards 11:00 to keep speed up?
3. Is apparent wind (which is greater strength than actual) one of the reasons that you can travel faster than wind speed? Eg hit 20+knots with 15 knots of wind?

TA.