Weather Helm/Lee Helm -What's The Diff?

[Scott T-Bird]

I feel i need to go on a religious crusade to dispel this myth.

I like how you brought up skiing. When you bury the rails with skis and snowboards you turn into the buried side. You dont bury tbe the left side of the board to whip a right hand turn.
QUOTE]

You must have missed the part about my explanation where I said a planing sailboard behaves similar to the way you ski, where you pressure the inside edge in a turn. A sub-planning board behaves the opposite. I'll have to admit that I spent just about all of the last decade of my windsurfing experience on planing sailboards. But when I learned on the original windsurfer (much of the time sub-planing), I quickly learned that when turning upwind, the correct footwork included pressuring the leeward rail, Of course raking the mast back was necessary as well ... in order to step around in front of the mast.

I'm not sure where religion falls into this, and I'm also not aware of any myth that you talk about. If you still have a sailboard, you'll have to reacquaint yourself with how it works!

 

[Scott T-Bird]

But a keelboat is the opposite.

Set a course, lash the tiller, and then put all the crew on, say, the port side. The boat will immediately head to starboard. It's completely counter intuitive, and I'm way too ignorint to explain it. But that's how it is.

Right, isn't that how a roll tack works?

 

[Scott T-Bird]

No, you do this to:
Decrease the wetted surface area of the hull, and
Allow gravity to help the sails hold their best airfoil foil shape

Ok, that, too

 

[BobbyFunn]

Windsurfing has tremenous appeal. Fits on roof rack, beach launch, perfect for days over 15 knots great for hot weather. Seems perfect for my off season. My experience is with snowboarding so the crossover should be easy.

The part that confuses everyone is that stupid CE picture of wind fore and aft of the CLR. Those books should be burned.

Everyone first sailing class (after the obligitory bowline lesson) shouldbe the instructor blowing on a pinwheel, then cutting all but one petal off and blow on it again. The sailboat is doing that 100% of the time there is wind.

Next lesson is tying a string to a mast about 1/2 way up RC mast and the student pulls the string in different directions (lift force) while the model is held near the keel joint.

That would show just about every essental force in sailing for entry level.

The key is the difference between the forces of the wind and the floation and the location of ballast versus flotation. Those two distances determine the center of the pinwheel.

 

[BobbyFunn]

Set a course, lash the tiller, and then put all the crew on, say, the port side. The boat will immediately head to starboard. It's completely counter intuitive, and I'm way too ignorint to explain it. But that's how it is.

This is easy to explain and understand.

Imagine yourself as king neptune. You see keelboats racing above you and rise up. You grab a fin keel by the bulb and hurl it like a dog toy as far as you can. (Crew is tethered, they'll be ok)

The boat spins very lopsided. If you slow time, you would see that the boat is spinning around a single point near the rear keel hull join. That point is following a smooth arch tbrough the sky, regardless of lopsided spin. I think that point is the center of mass (COM).

When floating that point should be directly below, in line with direction of travel.

When the boat is heeled over any amount that COM is shifted to the opposite side.

Heres the next point. If you apply a force to get the boat moving it ideally should be in a perfect line between the destination and the COM. Kerbal space program on a playstation 4 shows this easily. Any misalignment generates rotation and centrifugal forces.

If you have sails up the lifting/pulling force is way above the COM pulling some degrees away from your destination off to lee. Since the lift force is not the same as your destination and not in line with your COM. There is rotation around the COM.

If you are under power and heel with rail meat, it should be less noticeable since the prop is very close to the COM and in line with your destination. The rudder if applied, then provides a force not in line with your destination so there is rotation around the COM. If the prop or applied rudder force is below the COM the boat turns in. If the prop or applied rudder is above the COM you turn out.

Next time you are out with crew try to see if there is a difference between under sail and under power.

Fast power boats turn inwards since tbe COM is above the prop(s), keel boats turn outwards since the COM is just below the prop and rudder.