The Physics of Land Sailing
Sailing on water and sailing on land have some things in common, but they also have a lot of differences. In fact, a land sailboat is really more comparable to a glider on wheels than a sailboat [source: Weber].
Land sailboats usually have three wheels and one sail. They go too fast to use jibs or spinnakers. (Jibs and spinnakers are the two main types of headsails, or sails used in front of the mainsail, on sailboats.) Made by several manufacturers, land sailboats range in size from a sailboard (sort of like a surfboard with a sail) on wheels to a huge land yacht.
In smaller boats, the sailor may sit or lie on the frame. Usually, sailors steer with their feet, moving a T-bar, which basically is two pedals. You push with the right foot to turn left, and with the left foot to turn right. Steering with the feet leaves the hands free to use a rope (also called a line or sheet) to maneuver the sail. The sail is used primarily to adjust speed, not for steering. For some maneuvers, such as going around a racing maker, the land sailor will use the sail, but mostly just to adjust the speed to allow for accurate steering [source: Bassano].
One brand, BloKart, uses a hand-operated tiller, so disabled people can sail.The tiller is a lever that helps steer; on a BloKart, it's attached to the wheels, while on a sailboat, it's attached to the rudder underwater that steers the boat [source: Blokart]. In larger boats, the sailor may be enclosed except for the eyes and top of the head in a long, low craft. These sailors look like they've been stuffed, in a reclining position, into a close-fitting rocket ship or experimental aircraft with a sail. In racing, rules in some classes say that standard boats cannot be modified, while open classes regulate only the size of the sail and allow sailors to experiment with designs.
What attracts many people to land sailing is the speed. The speed record, set by Richard Jenkins in March 2009 at Ivanpah Dry Lake on the Nevada-California border, is 126.2 miles per hour (203.1 kilometers per hour). The wind that day was 40 miles per hour (64.4 kilometers per hour) [source: NALSA].
The physics at work is the same as in water sailing, but the results are different because the conditions are different. Forces make things move, and forces can slow or stop moving objects. In sailing, the forces causing motion are the push of the wind on the sail and the pull of the air passing over the curve of the sail, creating lift much like on an airplane wing (but imagine it turned sideways). The forces holding back a water sailboat are the friction of the water on the hull and some friction of air on the boat and sails.
Land sailboats can go faster because their wheels face much less friction on dry surfaces. Because the whole boat is exposed to the air, land sailors meet more air friction, but that doesn't slow a boat nearly as much as water friction [source: Brinson].
Land sailing isn't just sitting back and letting the wind push the boat, though. Sailors must move the boat side to side to maintain that lift.
What's it like to go land sailing? Read on.