Cruising (sailing)
Cruising means when sailing , in a "zigzag course" to approach a destination that is in the wind . Because of the headwind , it cannot be sailed straight to the sea.
Thus, cross strokes are required in which multiple turning maneuvers are performed. After each tack, sailing is carried out as close to the wind as possible , alternating on port- bow and starboard- bow, in order to approach the target.
The so-called turning angle describes the most favorable angle between two upwind courses (shown in white in the picture). This measure of the cruising characteristics of a ship indicates how close to the wind it can still travel well. For regatta ships, the turning angle is less than 70 °, for cruising yachts it is often 100 ° and more. A goal that - in relation to the wind direction - is within a sector the size of the wind angle can only be reached by crossing.
The factor by which the route to be sailed on the cross is extended in contrast to the direct route against the wind is idealized . The resulting path difference (regatta boat 1.2 times the direct path or 1.6 times the direct path for a cruise ship) is considerable.
The square-rigged tall ship earlier trade navies often had very bad cross properties, therefore it is preferred to may be seen better wind conditions.
If the goal to be reached is not directly against the wind direction, cross- lashes of different lengths result, which are called holebug or stretch bows . On the shorter Holebug, you get “height” without getting much closer to the goal. On the longer stretching bow, you shorten the distance or walk directly towards the goal.
Sometimes downwind courses are also used; be it to take advantage of the higher speed of a spacer course , to drive at a more favorable angle compared to trailing waves, to prevent the dangers of an involuntary jibe in the case of unsteady winds or to take advantage of gusts of wind . Instead of several turning maneuvers, a series of jibes is sailed when cruising in front of the wind .
How to sail against the wind
The main effect is caused by the so-called wing effect, which works similarly to the wings of an airplane. More detailed explanations can be found in the article sailing, section wind flow on the sail .
Another effect arises from the deflection of wind power through the sail and keel:
The sail is at a smaller angle to the wind than the length of the boat. Only the part W Q of the wind power W standing at right angles to the sail acts on the mast and thus on the boat. The part W L parallel to the sail passes ineffectively along the sail. Since the sail and the boat keel are at an angle to each other, W Q acts across the sail, but at an angle to the keel on the boat. Of this oblique force, only the part of the force acting parallel to the keel leads to movement, the other part only causes undesired heeling and drift.
Cruising from the wind
Crossing in front of the wind means with an aft wind (tail wind) in a "zigzag course" to approach a destination that is roughly in the direction of the wind. Although the direct route to the destination is shorter, cruising before the wind offers advantages:
- The yawing or fiddling of the boat (rolling around the longitudinal axis) is reduced.
- No risk of a patent jib (accidental, dangerous crossing of the tree to the other side of the boat).
- Higher boat speed, so that the destination is usually reached faster than the direct route. The reason for the higher boat speed is that the sails have a more favorable flow due to the apparent wind than when driving “flat in front of the wind”, and thus the dynamic lift on the sail is greater.
- Tactical advantages in regattas