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Wednesday, December 18, 2013

Learning to Sail a Catamaran


I had been sailing for the past week at Club Med in Ixtapa and have learned to skipper a 13' Catamaran. Up until now, I have been partial to monohulls, mainly since I have been told by many that Catamarans are "slow, difficult, and boring." Good news: Catamarans are really misunderstood. First off, they are capable of speeds impossible to monohulls. That explains why they are used in America's Cup. (I still prefer Sunfishes, though). Going downwind, they are stable, though not very great across-wind. These boats are easy to learn, yet hard to master. A few days ago, I was in a regatta (won 2nd!) and seven teams entirely failed from trying to tack too quickly! Other than that, they are quite similar to standard sailboats.


The three main variants of sailboat hulls. (Yes, there are Pentamarans, as well.)

The most common dual hull design engineered for speed and buoyancy.


Terminology:

Mast: the vertical beam connecting the sail(s) to the boat.

Boom: the horizontal beam weighing down the sail, adjacent to the mast.

Hull: the submerged part of the boat that is buoyant. In this case, there are two.

Main Sail: self-explanatory 

Jib: the optional, smaller aft sail.

Rudder: the flat board used to turn the boat 

Tiller: the pole used to steer the rudder.

Main Sheet: the line used to trim the main sail.

Downhaul: the line used to firm the main sail.



A Hobie Cat Wave. This is what I've been sailing. These boats are very simple; they have no jib nor spinnaker.



Even America's Cup uses Catamarans.


The Ultimate Challenge: tacking a Cat. The only succesful strategy is to come about as slowly as desired, being cautious about losing wind. Catamarans can't do sharp turns, attempting one will result in being caught in irons.


These are the main points of sail (in French). The red arrow represents wind. Sails must be trimmed in these positions to travel in certain directions. The closer you are to the wind source, the more you trim the sail in. If the wind is at your back, you must let the sail out to a maximum. If the wind is blowing across, you let the sail halfway out. 




The source that the wind is coming from, or irons, is impossible to sail in. 



This is simply the two former charts without the boat graphics. Notice how some points are broader than others? This is because of wind. Just like it's easier to walk downwind, it's easier to sail downwind. You have to force a boat upwind, and even then, it tends to try to go downwind.


You can't sail into the wind directly, no matter how hard you try. But you can tack upwind, or sail close to the wind source. If your boat is close-hauled, you can make a zigzag pathway to your destination.


Guess what: sailing upwind is physics! This is because you are sailing almost opposite to the wind and the shape of the sail is generating lift. The boat is experiencing sideways force and a bit of forward force. Since it has a rudder, the vessel is prevented from drifting sideways by itself.








That's how you sail a Catamaran! I promise, it's much simpler than it looks!















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