On a good day, you can make it through the course. On a bad day, you are late after No. 3, fight to make No. 4 and blow No. 5. Your turns look good, and you are holding a strong body position through the wakes. So why can't you get all six with any consistency?
Ron Thompson of the Orlando International Waterski Center has an answer. He's pretty sure you're losing angle without even knowing it. Here's his solution:
A lot of intermediate skiers will come out of the turn with good angle and body position and then flatten out past the second wake in anticipation of the turn. When you flatten out, you lose angle and end up late.
To overcome this tendency, I suggest you work at building a progressive edge, which means your hardest lean is actually through the second wake and into the edge change. At the end of the lean, transition immediately from edge to edge, then simply relax your knees and ankles and let the ski make the turn.
Edge hard past the wakes, don't let the ski go flat, and make a crisp edge-to-edge transition into the turn. Do these three things correctly and you will stay ahead of the buoys and improve your slalom passes dramatically.