SAILING TIPS Mike Huston To Jibe or Not to Jibe
Jibing is similar to tacking, it is used
to change from starboard to a port tack (or vice versa) when sailing downwind. The main difference is the wind crosses the stern on a jibe instead of crossing the bow as it does on a tack. Most sailors have a healthy respect for this maneuver – and for good reason. The primary issue is the main sail, during a jibe it can swing across the boat with a great deal of speed and force. During a tack the sails become
unloaded and luff as the wind moves across the bow of the boat. This creates a lull wherein the crew has time to safely change sheets and reload the sails. When jibing in anything more than a modest breeze the sails change sides in the blink of an eye. They go from fully loaded to unloaded slowly as the boat changes course but then go to fully loaded very quickly as the wind gets behind the sail. This is the point of danger. Bad things can happen on
uncontrolled jibes; people are often hit or knocked overboard and/or gear can break – all the way up to de-masting. This is why so much has been written and taught around avoiding accidental jibes. In this article I am hoping to share some information and techniques that will hopefully make jibing a safe and useful maneuver.
Wind Relative
Velocity Force 5 kts
10 kts 15 kts 20 kts 30 kts 40 kts 60 kts
1 4 9
16 36 64
144 Before getting into the techniques,
let’s talk about wind and the force it puts on the sails and rigging. The amount of force (or pressure) the sails feel changes as wind velocity increases. But this change is not linear, in other words, the force of a 20 knot wind is not twice that of a 10 knot wind – it is actually 4 times stronger. This is because force is proportional to the square of the wind’s velocity. Just to show the impact of this, here is a table showing the relative force at different wind speeds. In the table I arbitrarily assign a force of 1 to a 5 knot wind. As you can see, the force increases rapidly as the winds get stronger. These first two techniques revolve
around making jibes safe by avoiding them.
Avoiding Accidental Jibes Because accidental jibes are
unexpected they are the most dangerous kind. Too often people are on deck or up adjusting sails and this activity distracts the helmsperson just enough to cause a course change. And when running down wind it does not take much of a course change to cause a jibe – 10-20 degrees is enough. So, the first prevention tool is steering a consistent course relative to the wind. Tool number two is adding a preventer that holds the boom on the lee side. Just be sure the line is not nylon; nylon stretches too much and will allow the boom too much movement. Therefore, don’t use a dock line as a preventer line. And the third tool is to use a series of broad reaches instead of running dead downwind. This puts the wind more on the side of the boat and creates a larger margin of error in steering. And if you are not running a spinnaker it will likely get you there sooner. If the wind is blowing hard use a ‘Chicken’ jibe to change from one reach to the other (see below).
“Chicken” Jibe This is a slang term for doing a tack
instead of a jibe. This usually involves bringing the boat up to close hauled,
48° NORTH, JUNE 2011 PAGE 52
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