2006-09-05 23:05:39 · 7 answers · asked by sweetjulia 1 in Science & Mathematics ➔ Physics
ERRRRRR, wind!?!
2006-09-05 23:07:48 · answer #1 · answered by pompeyfc 3 · 0⤊ 0⤋
Of course the wind always wants to push a sailboat downwind. However, the keel prevents the boat from slipping sideways. This forms a wedge between the force of the wind and counter-force due to resistance of the water (like pinching a slippery grape?) and the wind pushes the boat in the direction of the keel. A sailboat can easily sail in the direction of the wind (downwind) when the wind is blowing from the stern (rear). However, the boat can also sail at an angle of about 45 degrees into the wind because the wind blows the sails into a curve (airfoil) that has lift (forward force) similar to the action that hoists a kite. But without a keel, the sailboat can only go with the wind. The sailboat sailing into the wind must tack to port then starboard then port, etc. to eventually make progress "straight" ahead. Large sailboats have fixed keels (I sailed on one having a 7-ton lead keel!) but smaller sailboats have a retractable "center board" that serves as a keel.
2006-09-06 08:05:44 · answer #2 · answered by Kes 7 · 0⤊ 0⤋
You can sail in any direction except directly into the wind, using the wind through your sails to push or pull the boat forward. Obviously downwind is the best case scenario but you can sail in all directions except directly into the wind. If your course is a point that is directly into the wind you have to sail in a zig zag (called reaching) pattern at a 45 degree angle to the wind to pull the boat forward until you reach your destination. There are tons of books on the subject and naturally lots of hits about sailing in a google search if you want to learn more.
2006-09-06 06:20:36 · answer #3 · answered by Windseeker_1 6 · 0⤊ 1⤋
Same principle as the airplane. The curvature of the wing provides an uplift when the plane moves with a forward thrust provided by the jet. The sail is also curved when its surface is presented to the wind. The thrust provided by the different velocity going over the sail is what provides the thrust to the boat.
2006-09-06 06:11:22 · answer #4 · answered by Tom Cat 4 · 0⤊ 1⤋
Except for when the wind is directly behind it (which pushes against the sail via friction) the sail actually acts like a planes wing, slicing the air and pushing it aft. This is how wind from the side can push a boat forwards.
http://www.sailtheory.com/sail.html
2006-09-06 06:18:37 · answer #5 · answered by Phil M 2 · 1⤊ 0⤋
wind is caught in the sail and when the force of the wind exceeds the force needed to move the boat the the boat is propelled forward.
2006-09-06 06:11:22 · answer #6 · answered by Anonymous · 0⤊ 0⤋
tidal force wind force
2006-09-06 06:59:18 · answer #7 · answered by Anonymous · 0⤊ 0⤋