Monday, February 25, 2013

The Vang as a Throttle - Shifting Gears Downwind


If you plan to sail 420’s or FJ’s for your high school or college, you will be exposed to a type of sailboat racing unlike any other in the world.  The courses are short, the boats are as even as they’ll ever get, you sail a ton of races, and you have more opportunities to pass boats downwind than you ever have.  Due to the nature and location of these types of races, there are fewer ways to make the boat go faster on its own.  However, there are more opportunities to catch bands of pressure that will slingshot you to the front of the pack.  In order to take full advantage of the puffs, it takes a lot of communication with the person you sail with, and a proper understanding of how to use the vang.

First, it is important to understand the best angle to sail a 420 or FJ at on a wing downwind.  For example, as you let the main sail out on these boats, you will notice that where the boom makes contact with the side stay is far aft of reaching 90 degrees from the centerline of the boat.  Thus, the boat is more effective sailed on a low broad reach angle than it is when it is sailed by the lee.  Additionally, off wind it is important to get the top most batten to the point where it is 90 degrees, or perpendicular, to the centerline of the boat.  This typically will require a looser vang, enabling the leech to spill forward of the boom and allow some flow across the sail when you are going downwind.

While you sail the main at a low broad reach angle, you will naturally have to sail the jib by the lee with the wind entering the jib’s leech and exiting the luff.  When you do this, you can use the jib sheet similarly to the vang.  Pulling down hard on it will close the jib’s leech, while lifting your arm higher will open it.  Steering at your general downwind angle, where the jib is by the lee, you will want to lift up the jib’s clew a little bit with your arm to open up the leech and facilitate flow over the sail.  How high or low you lift the jib’s clew will depend on the depth of your angle and the amount of pressure you are sailing in.  Now, let’s take a closer look at your actual vang.  

It is best to think of your vang as a throttle downwind when you are sailing a 420 or FJ wing on wing.  Imagine that you are sailing on a wing at your typical downwind angle.  As a big puff hits your sails, what happens?  If you haven’t put more vang on as the puff hits, the boat will heel hard to windward for a few instants and will feel out of control.  In really windy conditions, the boat may even flip over.  Whenever this happens to your boat, it is a signal that you are spilling breeze out of your sail.  The end result is lost power and speed.  This is much more obvious when you are sailing next to someone who is adjusting their vang correctly, as they jump further and further ahead of you through each and every puff and lull.

Communication between the crew and skipper is essential for proper execution.  As you sail together downwind, the crew should face aft, looking for new puffs and, directing the skipper toward them.  As a new puff is about to enter the sails, the crew should pull vang on so that the batten remains perpendicular through the duration of the puff, and ease it off again as the breeze rushes past the boat.  If executed correctly, the boat will remain stable with no alteration in its heel when the new breeze hits the sails, and it will surge forward with new power and speed.

Quick Tip 1: If the main is not sailed by the lee, the tell tale on the upper batten will want to move forward and out of sight about 50% of the time, floating backward 50% of the time.

Quick Tip 2: In the rare circumstance that you sail the main by the lee and the jib at a traditional angle to the wind, it is best to ease the vang more than you normally would.  Remember, the leech of the main in this scenario is now the luff of the sail, and the luff and mast are the new leech.  If you are sailing in light air, or need to delve particularly far down by the lee, have the crew lift the boom upward to open the leech of the sail further and create more flow across the sail.  Furthermore, at this angle you can also pull down a little bit on the jibs clew in puffs to avoid spilling the breeze from the jib’s leech.

See you on the water,

Zim Coach

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