As your own experience should have already revealed - large, rapid rudder movements create drag which slows a boat's forward motion. Small, gradual rudder movements do not create so much drag and therefore allows the maximum possible forward momentum gathered from the previous leg to be carried into the next leg of the race. This gives you a serious tactical advantage because you don't waste precious seconds accelerating up to full boat speed. Study the way that consistent race winners round marks and you'll begin to notice this so-called tactical mark rounding technique.

Tactical mark rounding
File:Tactical late.png
File:Tactical wide.png
File:Tactical close.png
File:Tactical late recovery.png
File:Tactical perfect.png
File:Tactical room inside.png
static images wanted

Rather than sailing directly to the mark and slamming the rudder over for a sharp turn, sail wide of the mark and begin a gradual turn (try 10 degree rudder) well before your boat is abeam of the mark. Just how much before and just how much rudder angle is really a function of boat speed and boat design so practice starting that gradual turn at one boat length before and then increase the distance for higher boat speeds. Your aim is either:

  • to be on a direct course to the next mark if it is a reach mark or
  • to be on a close-hauled course if the next mark is to windward

As a practical matter there will be other boats trying to round the mark at the same time as you and the reason you need to practice the tactical rounding is to ensure that you not over shoot the mark and open up a door for another boat to sail between your boat and the mark. The notable exception is when rule 18 requires you to give mark room to another boat. Then, you must allow them room at the mark.

So you see it becomes a balancing act between making a wide enough turn to maintain as much forward momentum as possible while still closing the door on any opportunistic competitor over whom your boat has right-of-way. If you started your gradual turn in the ACC boat at one boat length before and one boat length abeam of the mark then the chances are you sailed too deep (overshoot) and you'll want to start the turn sooner and/or wider the next time. It is a very different technique when sailing a melges because the melges accelerates so much faster than the ACC but also can turn on a much tighter radius than the bigger ACC.