Power jibe
The power jibe (English: powerjibe or powergybe ) is a maneuver in windsurfing to reverse the direction of travel without reducing the speed. As with an ordinary jibe , the surfer makes a turn with the wind and not against the wind as in a turn .
The difference to the jibe lies in the gliding of the surfboard on the water (from approx. 20 km / h), whereby it can be steered into the curve with the feet. A successful power jibe is completed in gliding on the new course. This type of jibe requires increased skill.
description
The name is derived from the increased power with which the sail turns. The sail is kept tight during the jibe. Most of the time, the surfer hangs his jibe on the sail in a relatively stable position. At the end of the jibe you go ahead on the new course with the clew . By letting go of the sail hand and the increase in force in the sail on the new course, the sail turns quickly. The sail rotates around the axis of the mast.
When making the jibe, the changing apparent wind as the course changes must be taken into account. The board is steered with the feet, but a considerable part of the angular momentum comes from the leverage of the sail pressure point and the lateral pressure point . The jibe is initiated with a slight flare and pushing the sail forward.
The power jibe, next to the stop jibe, is the oldest jibe used on surfboards. On sinkers, it is a necessary element of mastering the surfboard, since with it the jibe remains without power for a short time. Shorter times for shifting the sail are only possible with the fully slid jib and the duckjibe. The disadvantages of the power jibe are the large forces to be applied by driving with the clew in front and the necessary short-term compensation of the large transverse force when letting go and taking the seal again.
Similar embodiments of the jibe on surfboards
Speedjibe
A clean, fully slid jibe differs from a power jibe in that the jibe is initiated before the downwind course has been reached. The sailor tilts his upper body forward with his knees slightly bent in order to maintain the optimum weight trim for gliding on. The glider's center of mass is, slightly inclined to the center of the curve, in the center of all forces. As a result, he no longer needs to "hold on" to the sail and can turn it relatively effortlessly and quickly, precisely at the moment of the lowest wind pressure on the downwind course. The sail is not rotated around the axis of the mast, but around its vertical mass axis. This reduces its moment of inertia . The angular momentum of the sail is achieved by simultaneously pulling with the mast hand and pushing with the sail hand . The mast hand pulls or pushes the tree over the other shoulder. The old sailing hand grabs the boom in the right place on the new side and becomes the new mast hand. Even small waves can have a considerable influence on the sequence of movements, depending on whether you drive them "uphill" or "downhill" at the crucial moment. For further optimization, the course of the jibe is set in such a way that at the moment when the board is on the downwind course (i.e. at the moment of the slightest propulsion), a small wind wave is ridden.
One-handed jibe
like speed jibe, but at the moment when the board is on the downwind course (i.e. at the moment of the lowest force), the sailor can release his sailing hand and, for example, spectacularly pick up an object floating in the water (or at least pretend to be). The forces acting on the sail at this moment are so small that the mast hand can continue to hold the sail in the correct position. The longer you stay in the downwind course, the longer the sail hand can remain free - but the more speed is lost. By entering the new course, the forces acting on the sail suddenly increase. By pulling or pushing forwards with the mast hand at the right moment, the sail folds over and the sail hand grabs the other side of the boom.
Racejibe
The sail is tilted jerkily and spectacularly to the leeward (sometimes almost down to the surface of the water) in order to drop . The fall off takes place very quickly and with a narrow radius. The greatly reduced projected area of the sail, caused by the inclined position of the mast, is tantamount to lowering, although the boom is first pulled tight at the beginning of this maneuver. The picture shows a moderate race jibe. The very forward leaning of the upper body with knees bent in order to keep the board as flat as possible on the water can be seen very clearly. The sailor has already retracted relatively far into the downwind course, so that the sail will be "shifted" in the style of the power jibe.
Duckjibe
More like the jibe on a sailing boat. The sailor "dives" under the boom to the other side. The sail does not rotate 270 °, but only about 90 °. This means that even less time is needed for "shifting" (→ longer time with pressure in the sail).
Other types of jibs
Stop neck
The sailor lies back with all his weight and hangs himself with long arms in the sail that is pushed forward. As a result, the surfboard sinks in at the back and the tip of the board rises out of the water. The effective lateral plan is shortened and the board turns almost like on a plate. The radical immersion at the rear also shifts the lateral pressure point to the rear, increasing the lever between the lateral pressure point and the sail pressure point and thus the angular momentum. On the new course, the body weight is quickly shifted forward again to avoid falling into the water. Due to the deep immersion of the stern, the speed is zero after the maneuver.
Jumped jibe (aerial jibe)
in sideshore conditions, the sail is shifted in the flight phase of a jump over a wave. It is landed on the front of the same wave and ridden again.
Individual evidence
- ^ Arno Krombholz: Structures of sporting techniques in windsurfing. Theoretical considerations and empirical studies for the determination of technology models. (PDF) Dissertation to obtain the doctoral degree in sports science in the subject of kinetics. 2009, accessed August 18, 2018 .