What Bob Hodges said.
If you are dreamy-eyed in a breeze (or initiate tiller movement but delay coming in), the A will tack by itself before you are ready, and now you are on the wrong side. Ooops, Splash.
Practice the hand changes and move properly and these little boats tack like a dream. Carving and HOLDING the tiller at the correct angle is critical to complete a fast tack, which is what Johnny Lovell is doing when he is watching the wake. Way cool = 13 seconds wire to wire? Less?