I have gotten a BWI before - not fun. I believe it is legal to drink and drive as long as you are under the limit. I usually drink once we have stopped and then have one of my friends or fiancee drive me home. I enjoy driving, but sometimes I really just like to get drunk and go for a ride. My passengers always drink.
In TX the implied consent law (don't blow and you go to jail) does not apply if your boat is under 50hp.