5 ms·

Great suggestions. >It's missing the force vector from the boat in the water. That's what really explains what is going on. The force vectors don't add up to t

Great suggestions. >It's missing the force vector from the boat in the water. That's what really explains what is going on. The force vectors don't add up to the motion shown. Yes. You see, I couldn't really isolate that vector. What I am doing is taking the force vector on the sail and taking the projection of it in the direction that the boat is facing. Actually, the forward force comes from the boat trying to move in the direction of the force of the sail. But ends up moving a bit forward because the keel is in a slanted direction to that movement. So even if I show that vector, the viewer probably wont still have any idea regarding where it came from.

dognotdog 12y ago
Aren't you forgetting about the keel/center board? The keel only produces lift when in motion, thus it is very important, as you can only start sailing upwind once you have a bit of speed. It's not the projection of sail force in direction of the boat that causes forward motion, but the addition of sail and keel forces.
pkghost 12y ago
This is a neat idea, but it's super confusing without the concept of the sail's curvature. AFAIK, sails work like airplane wings (not like socks), creating lift on the convex surface by virtue of faster moving air and lower pressure. Perhaps your model assumes the same, but it's not clear from the way the sail is drawn, and it looks like sailing down wind is just as fast as sailing somewhat across the wind, which is in fact the fastest way to sail.
- Sharlin 12y ago
  Airplane wings don't work like that; it's a common myth and does not really make sense. Wings generate lift by a rather straightforward utilization of Newton's third law of motion: they deflect air downward. Sails work the same way: they deflect air sideways. http://www.cam.ac.uk/research/news/how-wings-really-work http://www.cam.ac.uk/research/news/how-wings-really-work
  - Anderkent 12y ago
    Video that (i think) explains it better: https://www.youtube.com/watch?v=aFO4PBolwFg https://www.youtube.com/watch?v=aFO4PBolwFg

dognotdog 12y ago

Aren't you forgetting about the keel/center board? The keel only produces lift when in motion, thus it is very important, as you can only start sailing upwind once you have a bit of speed. It's not the projection of sail force in direction of the boat that causes forward motion, but the addition of sail and keel forces.

pkghost 12y ago

This is a neat idea, but it's super confusing without the concept of the sail's curvature. AFAIK, sails work like airplane wings (not like socks), creating lift on the convex surface by virtue of faster moving air and lower pressure. Perhaps your model assumes the same, but it's not clear from the way the sail is drawn, and it looks like sailing down wind is just as fast as sailing somewhat across the wind, which is in fact the fastest way to sail.

Sharlin 12y ago
Airplane wings don't work like that; it's a common myth and does not really make sense. Wings generate lift by a rather straightforward utilization of Newton's third law of motion: they deflect air downward. Sails work the same way: they deflect air sideways. http://www.cam.ac.uk/research/news/how-wings-really-work http://www.cam.ac.uk/research/news/how-wings-really-work
- Anderkent 12y ago
  Video that (i think) explains it better: https://www.youtube.com/watch?v=aFO4PBolwFg https://www.youtube.com/watch?v=aFO4PBolwFg