Courses to the wind
When sailing, a distinction is made between the courses to the wind according to the angle of incidence of the apparent wind in relation to the longitudinal axis of a sailing vehicle.
Apparent wind refers to the wind perceived on board, which results from the interaction of true , atmospheric wind and airflow . The apparent wind is also called on- board wind , its direction is indicated by the clicker (small flag) at the top of the mast of the boat. Depending on the course to the wind, the position of the sails and their trim (more or less curvature (belly) in the sail) differ .
The course only means the angle of the vehicle to the wind (0 ° in the wind to 180 ° in front of the wind ). For the nautical term course of a ship see course (navigation) .
In the wind
If the angle to the wind falls below the smallest possible sailable angle, then no more propulsion is generated. The boat is then almost in the wind and the sails are killing (flapping). A target that is in this wind sector can only be approached by crossing it. The size of the unsailable wind sector, known as the turning angle , is a measure of the cruising properties of a sailing ship; small turning angles mean good cruising properties.
The sailing maneuver, in which the bow of the ship is turned into the wind to stop (stopping the ship), is known as a shoot -out.
On the wind
Close to wind (also called wind ) describes a course in sailing where the angle of incidence of the apparent wind is less than 90 °. The smallest angle that can still be sailed is called high on the wind , close to the wind or opposite . For square sailors it is in the range of 80 ° to 90 °, for modern, for example, slup-rigged yachts , it is around 30 ° to 45 °, depending on the type of ship. On the other hand, full and at is the fastest course to windward where the helmsman - instead of “pinching height” - drops a little and makes sure that the sails are fully upright.
On a close-hauled course, the air flow along the sail is mainly used, similar to a wing on an airplane . The sails are brought close, that is, moved towards the center of the ship, and trimmed flat. Square sailors can hardly drive close to the wind because they get their propulsion mainly from the wind pressure in the sail.
It takes some sailing theory to understand why boats can turn upwind (zigzagging upwind ). It is possible, among other things, because sailing ships glide through the water much more easily in a forward direction than across it.
Half wind
Half wind describes a course in which the clicker blows approximately at right angles, so the apparent wind comes in at approximately 90 °. The sails are opened a little compared to the close- hauled course ("the pods lowered"). While most of the propulsion on a half wind course is still caused by the current on the sail, another part is also due to wind pressure on the sail.
Spacers
On a space sheet or space wind course , the apparent wind “coming diagonally from behind”, in seafaring terms: more aft than abeam , comes in ; the wind on space sheet courses is also referred to as a backstage breeze . Propulsion is optimized by an even more open sail position and a slightly more bulbous sail trim.
According to some authors, every wind is called “space” that lies between a close-wind course and a downwind course; accordingly, they regard half wind as a special case of clear winds.
Before the wind
Before the wind is a course where the apparent wind comes in from the aft , i.e. exactly from behind. Here the vehicle and the true wind (and thus also the apparent wind) have the same direction. On this course, propulsion is generated by wind pressure and no longer by currents on the sail.
Slupgetakelte boats are unstable when driving from the wind in their price behavior often and threaten "from the helm to run," making it easy to unintentional jibe may, a so-called patent or folding neck. To prevent this, a bull stand can be set up. To prevent the headsail from collapsing because it is in the slipstream of the main sail , it can be expanded , e.g. B. with a spinnaker pole . If the rigging takes place on the opposite side of the mainsail, this type of sailing is also known as butterfly sailing . In order to offer as much surface to attack as possible for aft winds, large, bulbous special sails, such as B. spinnaker or gennaker used.
Catamarans in particular , but also yachts and dinghies , generally reach a destination in leeward direction more quickly if they do not approach it directly, but rather cross in front of the wind, i.e. drive on changing spacing courses. There are several reasons for this: On spacer sheets courses, there are significant amounts of dynamic lift on the sails . In addition, the speed of the on- board wind and thus the flow speed of the sails is greater. Another reason is of a hydrodynamic nature: especially in sailing vehicles with little buoyancy in the bow area, such as B. in catamarans or classes with narrow hulls, when sailing in front of the wind - due to the leverage of the mast, which absorbs part of the sailing forces - the bow is pushed down into the water and there is increased water resistance.
Especially when the swell is high, cruising in front of the wind is preferable to butterfly sailing, also for safety reasons, because the risk of a patent jibe is very high in the butterfly if the course cannot be kept very precisely.
Further dependencies
It is not possible to generalize on which course to the wind sailing vehicles sail best or reach their highest speed, as this depends not only on the ship's construction and the specific hull speed , but also e.g. B. also on the type and extent of the sails , the respective wind speed and the currently prevailing waves . For example, frame-rigged tall ships, such as the earlier commercial sailing ships, are predestined by their design for courses on which moderate winds come in almost astern. Racing yachts , on the other hand, can certainly reach their maximum speed on close-hauled courses if they are not hindered by heavy seas. You are faster there than even on a downwind course, where the sail area is enormously enlarged by huge spinnakers . Because - except on courses in front of the wind - the apparent wind speed is always greater than the true wind speed, it is possible to sail faster than the (true) wind .
Many cruising yachts reach their Standardbesegelung (mainsail and Genoa) in moderate, half or slightly aft incident wind their optimum at which the sails can be fully set and the boat not overly heeled ( after Lee tends ). On this course, the drift by which the wind offsets the boat in relation to the heading is also moderate. Sailors on dinghies take contrast themselves to the boat by a higher drift into account, planing conditions to slide to get. Due to the reduced water resistance they achieve a sudden increase in speed.
literature
- Werner Kumm among others: seamanship. Yachting manual. Published by the German Ocean Sports Association "Hansa" e. V. 27th edition. Delius Klasing Verlag, Bielefeld 2005, ISBN 3-7688-0523-9 .
- Roland Denk: The great manual of sailing. BLV, Munich / Vienna / Zurich 1981, ISBN 3-405-11829-8 .
- Roland Denk: Learning to sail with questions and answers. 4th edition. Delius Klasing Verlag, Bielefeld 2009, ISBN 978-3-7688-1480-5 .
- Heinz Overschmidt, Ramon Gliewe: I'm learning to sail. With a catalog of questions about the basic sailing license. 13th edition. Delius Klasing Verlag, Bielefeld 2010, ISBN 978-3-7688-3136-9 .
footnote
- ↑ In the opinion of some authors (e.g. Roland Denk) the course names should not refer to the apparent but to the true wind. However, this requirement, which is derived from sailing theory, has, probably for practical reasons, neither in everyday use nor in specialist literature. However, the courses for the wind when ice sailing are related to the true wind .