Windward and empty greed
As weather helm refers to the tendency of a ship , especially a sailing vessel , at midships fixed rudder according Luv , ie in the direction of the wind to rotate. The opposite behavior, according to Lee to aspire to is called Leegierigkeit .
Sailing boats and sailing yachts
Play of forces between the sail pressure point and the lateral pressure point
At the sails pressure point (also sails center of gravity S), in which one can think of the forces of the wind on the sail as being combined, essentially two forces act on the sail or the boat: The propulsion V of the wind pulls forward and the wind pressure creates one Lee shear force Q. At the lateral pressure point (also the lateral center of gravity ) under water, two opposing forces act, namely the water resistance or form resistance Wf, which counteracts the propulsion, and the lateral resistance Wl, which counteracts the leeward pressure on the sail and thus the heeling (lean) of the boat caused. The force couple propulsion vs. Water resistance (blue, middle illustration) creates a torque that turns the bow of the boat in the direction of the wind, because the sails pressure point is leeward of the lateral pressure point due to the heeling of the boat (light blue).
The force couple lateral wind pressure vs. Lateral resistance (red, right illustration) creates a torque that turns the boat to leeward, as the sail pressure point is selected so that it is in front of the lateral pressure point when the trim is correct (orange). Both torques are roughly in balance on a well-trimmed boat. The remaining torque can be corrected by turning the rudder slightly.
Correction of greediness and greediness
The windwardness increases if the sail pressure point is too far back or too far out, i.e. H. if the boat heels too much. Additional heeling increases the windwardness because the lever arm for propulsion Hv becomes longer. The leverage increases when the pressure point of the sail moves too far forward, because then the lever arm for the lateral force Hq becomes larger. If you are greedy, the following measures will help restore balance:
- Shifting the sail pressure point forwards by reefing the mainsail or striking the foresail ,
- Displacement of the Lateraldruckpunktes according aft by moving the crew weight,
- Reduction of heel by reefing , by shifting the crew's weight to windward or by moving the traveler to leeward.
A slight eagerness to windward is often desirable to make steering the boat easier. It is also of advantage for safety if, for example, if the tiller breaks, the rudderless boat shoots independently into the wind , that is, turns to windward and thus comes to a standstill. It is also a common case that the boat heels so much (due to a gust) that the rudder breaks and the resulting strong windwardness causes the boat to "shoot into the sun" in an uncontrolled manner . Empty greed is almost always undesirable.
Sailing surfboards
A windsurfer uses the windward or leeward eagerness to steer his surfboard: by tilting the mast across the wind direction, he changes the position of the sail pressure point and thus, depending on the desired change of direction, causes windward or leeward eagerness.