EP0909703A2 - Ship's rudder - Google Patents

Abstract

In the side surfaces (12,13) of the rudder blade (1) outlet apertures (3) are arranged for a fluid and/or gas-form medium. The outlet apertures are provided in the front third of the rudder blade in the direction of travel of the vessel. Further outlet apertures are distributed over the side surfaces of the rudder blade. They comprise slots running vertically to the direction of travel of the vessel. The cross-sections of the outlet apertures and/or the outlet speed of the medium are controllable independently of each other on both side surfaces of the rudder blade. The outlet speed of the medium is variable by means of a feed device (5) arranged in the vessel and the medium is fed via a conduit (20) positioned over the rudder shaft (2) connecting the rudder blade with the hull of the vessel.

Description

The invention relates to rudders for watercraft according to the preamble of claim 1.

Rudders for watercraft are usually one vertical axis, which the rudder with the wheelhouse connecting and guided by a hull-proof coker Rudder shaft, swiveling to each side through the inflow of the aileron with a streamlined profile due to the screw or travel current of the watercraft a rudder pressure is created, which turns into an against the Directional resistance component and at a deflection of the rudder from the middle or Normal position in a direction transverse to the direction of travel control or effecting the control of the watercraft Split rudder force.

Due to the profile body of the rudder, the rudder force through the rudder pressure side facing the inflow and applied the rudder suction side facing away from the inflow, the rudder pressure side about a third of the rudder transverse force and the rudder suction side about two thirds of the Rudder force.

A vortex-free flow onto the rudder only occurs then when the inflow is aligned with the longitudinal axis of the profile is or runs perpendicular to the rudder stock or forms a relatively small angle with it. At larger deflections of the streamlined rudder body the flow is interrupted on the rudder suction side just behind the profile head of the streamlined rudder and there is a strong on the rudder suction side Vortex formation. This has a significant reduction the rudder transverse force used to control the watercraft and a significant increase in drag of the rudder. For this reason such rudders only work up to a deflection from approx. 25 ° to 30 ° rudder position satisfactory. For larger ones The rudder lateral force drops due to the rudder suction side no longer flows around due to the suction side tear becomes.

These undesirable phenomena can largely be caused by this be suppressed that at the point where the flow to the Tearing tends to be caused by a nozzle-like narrowing Splitting vigorously flowing liquid tangential to the wall is fed. This is compared to the inflow of the profile body without additional gap flow for larger ones lateral rudder positions achieved a greater lateral force and also the flow resistance of the rudder body reduced due to the suppression of vortex formation.

Such an arrangement is known from DE-PS 665 716, a streamlined one on either side of the rudder head Rudder rudder symmetrical to its median plane two wing-like curved pre-profiles by means of ribs or the like attached and arranged so that a wide opening remains between the leading edges thereof, which narrows in two in a nozzle-like manner Rudder head forked along channels.

Also to avoid a suction side tear is off GB 2 021 062 A is designed as a so-called rotor rudder High-performance rudder known from a main rudder blade and a hinged fin rudder blade exists, which deflects independently of the main rudder blade can be. Instead of a curved rudder head is on the front edge of the rudder is cylindrical or cylindrical Rotor arranged on the suction side in the direction of Inflow is driven all round. By means of the rotor even at large rudder positions, energy becomes the rudder suction side led and avoided the suction side tear. Also at Rudder positions up to 50 ° result in a large total rudder force and thus for effective control of the watercraft.

This type of high-performance rudder is disadvantageous Need at the front edge of the rudder, the one extremely stressed position, a constructive to install complex rotor with associated drive, depending on the rudder position and thrust load on the ship's propeller at high speeds in only short time intervals must be reversed to the rudder suction side To supply energy.

The object of the present invention is to provide a rudder for watercraft without additional attachments or moving parts outside the rudder blade both the resistance component directed against the direction of travel to reduce the rudder as well as a rudder deflection maintain the effectiveness of the rudder suction side.

This object is achieved by the features of Claim 1 solved.

The solution according to the invention creates one designed as a thruster High-performance rudder for watercraft, in which a suction side tear even with large rudder positions prevented and thus built up a maximum rowing power and its resistance component directed against the direction of travel both in the neutral middle position as is also minimal with all rudder deflections. This effect without additional attachments or moving parts achieved outside the rudder blade, so that the strength values of the rudder are not affected and no complex constructions are required.

The effect of the thruster is comparable to that Effect of a pipe bend that affects the rudder blade incoming flow deflects on both sides and thus prevents a suction side tear in the event of a rudder deflection or with normal rudder surface resistance belittles.

Although it is basically known from aircraft technology, in aircraft wings, high-energy air into the boundary layer blow in, in this way a detachment of the To prevent boundary layer, however, this principle either to increase buoyancy or to generate Adjustment forces used for a pendulum rudder. Such Arrangement is known from DE 15 06 567 A1, in which either in the top or bottom of a Pendulum rudder running current approximately at right angles to the current standing veil of a liquid, gaseous or powdery Control medium is blown out. The blown out Medium is used to keep the free flow around the Influencing rudder and in this way the adjusting forces for the rudder to generate.

From DE 30 10 431 A1 it is known the boundary layer of an immersed flow body through a gaseous one accelerate or detach liquid medium in order to to reduce the surface friction resistance. To this Purpose is through nozzle-like holes in the outer Ship wall of a watercraft pressurized gas into the fairway directed so that the flowing out through the nozzles Compressed gas on the surface friction resistance Boundary layer strikes and this for acceleration and Detachment brings.

An advantageous embodiment of the invention Solution is characterized in that the outlet openings on the front third in the direction of travel of the watercraft of the rudder blade are arranged. Because the suction side tear occurs with growing rudder positions on this side, is an introduction of energy into this area of the rudder blade most effective on the respective rudder suction side, to achieve a large total rudder force and to continuously flow around the rudder suction side.

The arrangement of further outlet openings distributed over the entire side surfaces of the rudder blade serves to prevent cavitation by blowing out the endangered Reduce or prevent spots on the rudder blade. In addition to cavitation safety, this can also improve propulsion can be achieved by, for example, both sides of the rudder blade is blown out and thus Steam bubbles can be avoided.

Advantageously, several outlet openings in Direction of travel of the watercraft one behind the other and / or staggered with each other, the outlet openings at least over part of the height of the rudder blade can be distributed.

The outlet openings preferably consist of vertical slots extending to the direction of travel of the watercraft.

By changing the cross section of the outlet openings can with constant pressure of the liquid and / or gaseous medium the exit velocity of the medium be changed to the different conditions, such as rudder angle, speed, rudder blade profile and the like to take into account. Alternatively can change the exit velocity of the medium the flow rate or the medium pressure can be varied.

By individual connection which is distributed over the rudder head arranged outlet openings with a conveyor for the medium as well as by individual or Group control of the cross-sections of the outlet openings the outlet speed of the medium can both side surfaces of the rudder blade preferably independently can be controlled from each other. In particular, the The medium exits via the height of the rudder blade controllable.

According to a further feature of the invention, the exit of the medium on both side surfaces of the rudder blade in Asymmetrical with respect to the vertical axis of the rudder blade controllable, taking into account the propeller twist the asymmetrical blowing out to a further improvement propulsion and avoidance or reduction of cavitation symptoms.

The conveying device for the medium can optionally in Rudder blade or be arranged in the watercraft, whereby with an arrangement of the conveyor in the watercraft the medium is routed via a line, through which the Rudder blade connecting to the hull of the watercraft Rudder and / or for the management of the rudder is led through the koker serving the ship wall.

If the conveyor is arranged in the rudder blade is preferably the suction opening for the liquid medium arranged in the rudder blade itself, especially on the leading edge of the rudder blade at the level of the propeller shaft.

Another advantageous embodiment of the invention Solution is characterized in that the leading edge of the Rudder blade consists of an anchor head that with the through the rudder body bounded by the side surfaces of the rudder blade is connectable and that the outlet openings between the End faces of the side surfaces and the side edges of the anchor head are trained. By changing the distance the anchor head to the rudder body can be the size of the Outlet openings in a simple and reproducible manner can be set.

The rudder blade consists of a profiled rudder body and a domed rudder head and from the rudder head to one Trailing edge of the rudder blade converging side surfaces, so the outlet openings are preferred in the the area of the side surfaces adjacent to the rudder head.

With a trained as a high-performance fin rudder Rudder with one on the rear edge of a main rudder blade hinged fin rudder blade can in the direction of travel of the watercraft front third of the main rudder blade Outlet openings for a liquid and / or gaseous medium can be arranged. In addition, in to the linkage of the fin rudder blade to the main rudder blade subsequent front third of the fin rudder blade Outlet openings for a liquid and / or gaseous Medium can be arranged.

Figur 1 -

eine schematische Darstellung mehrerer konventioneller Steuerruder sowie des erfindungsgemäßen Strahlruders bei unterschiedlichen Ruderlagen sowie die dazugehörigen Strömungsverhältnisse und Ruderquerkräfte;

Figur 2 -

eine schematisch-perspektivische Seitenansicht eines Steuerruders mit Austrittsöffnungen für ein flüssiges Medium;

Figur 3 -

eine schematisch-perspektivische Frontansicht des Steuerruders gemäß Figur 2;

Figur 4 -

eine schematisch-perspektivische Seitenansicht eines Steuerruders mit Austrittsöffnungen für ein gasförmiges Medium;

Figur 5 -

einen Querschnitt durch den Ruderkopf gemäß den Figuren 2 bis 4 mit fest einstellbaren Austrittsöffnungen;

Figur 6 -

einen Querschnitt durch den Ruderkopf gemäß Figur 5 mit verstellbaren Austrittsöffnungen;

Figur 7 -

einen Querschnitt durch den vorderen Teil eines Steuerruders mit einem Ankerkopf zur Einstellung der Größe der Austrittsöffnungen und

Figur 8 -

ein Diagramm mit dem Verlauf der Ruderquerkraft und des Ruderwiderstandes in Abhängigkeit von der Ruderlage bei einem Normalruder, einem Hochleistungs-Flossenruder, einem Rotorruder und einem erfindungsgemäßen Strahlruder.

The idea on which the invention is based will be explained in more detail with reference to exemplary embodiments shown in the drawing. Show it:

Figure 1 -

is a schematic representation of several conventional rudders and the thruster according to the invention with different rudder positions and the associated flow conditions and rudder transverse forces;

Figure 2 -

a schematic perspective side view of a rudder with outlet openings for a liquid medium;

Figure 3 -

a schematic perspective front view of the rudder according to Figure 2;

Figure 4 -

a schematic perspective side view of a rudder with outlet openings for a gaseous medium;

Figure 5 -

a cross-section through the rudder head according to Figures 2 to 4 with fixedly adjustable outlet openings;

Figure 6 -

a cross section through the rudder head according to Figure 5 with adjustable outlet openings;

Figure 7 -

a cross section through the front part of a rudder with an anchor head for adjusting the size of the outlet openings and

Figure 8 -

a diagram with the course of the rudder transverse force and the rudder resistance as a function of the rudder position with a normal rudder, a high-performance fin rudder, a rotor rudder and a thruster according to the invention.

The flow profile shown in FIGS. 1a to 1d with different rudder types and different Rudder positions and the resulting rudder transverse forces clarified on the rudder suction side and the rudder pressure side the effectiveness of the thruster according to the invention, in particular at large angles compared to the normal position. At Rudder positions below 25 ° are the normal rudder NR according to Figure 1a both on the rudder pressure side and on the The rudder suction side flows evenly, so that an effective Rudder lateral force is built up, which is one third from the rudder lateral force RKD on the rudder pressure side and to two thirds from the rudder lateral force RKS on the rudder suction side put together.

With a rudder position shown in FIG. 1b of more than The rudder transverse force drops by 25 ° on the rudder suction side, since the rudder suction side is not due to the suction side tear flows around more.

According to Figure 1c, the same conditions also occur a high performance fin rudder when using rudder positions an angle of more than 25 °. Also in In this case, the suction side flow breaks at the fin rudder FR from and the rudder transverse force is exclusively by the rudder lateral force RKD on the rudder pressure side applied, but according to the schematic representation in Figure 1a only about a third of that for control effective rudder transverse force.

In Figure 1d, the flow conditions in an inventive Thruster and a rudder deflection of more shown as 25 °. As a result of the outflow of a liquid and / or gaseous medium on the rudder suction side a suction side tear is avoided and the effective rudder transverse force as with small rudder positions of less than 25 ° to a third from that on the rudder pressure side rudder force and two thirds from the the rudder suction side together.

Figure 2 shows a side view and Figure 3 in one Front view in a schematic perspective view a rudder blade 1 of a thruster according to the invention. The Rudder blade 1 consists of a profile body with a Leading edge 11, which is profiled and spaced apart Side surfaces 12, 13 merges, which in turn to the rear edge 14 of the rudder blade 1 converge. The rudder blade 1 is connected to a rudder post 2, which by one, not shown, with the hull of the watercraft firmly connected koker is and in one Wheelhouse ends that with appropriate control facilities is provided for changing the rudder position.

In the areas of the side faces adjoining the leading edge 11 12, 13 of the rudder blade 1 are outlet openings 3 intended for a liquid and / or gaseous medium. These outlet openings 3 are preferably designed so that the medium is in the direction of travel, that is, from the leading edge 11 directed towards the rear edge 14, from the outlet openings 3 flows out.

The outlet openings 3 can be designed differently as well as arranged in different configurations. For example, one of the top edge 15 of the rudder blade 1 to its lower edge 16 continuous gap in both side surfaces 12, 13 of the rudder blade 1 in the same Distance from the leading edge 11 possible. Another Embodiment can consist in that according to FIG Exit gaps in each side surface 12, 13 in the top and the lower half of the rudder and each one Medium line 41, 42 connected to a conveyor 5 are.

The conveyor, preferably consisting of a pump 5 is via a medium supply line 40 with a Inlet 4 connected through which the liquid in this case Medium sucked in and via the medium line 41, 42 to the Exit openings 3 is conveyed where it with a predetermined Exit speed from the exit openings 3 exit. The power supply of the conveyor 5 takes place via a cable 51, preferably by a Bore 20 in rudder post 2 or through the koker is.

As an alternative to arranging a suction opening 4 at the level of Propeller shaft on the leading edge 11 of the rudder blade 1 a supply of a liquid medium on the upper edge 15, the lower edge 16 or on both side surfaces 12, 13 of the Rudder blade 1 possible.

Instead of a continuous column there are also several individual one behind the other and / or staggered Column predictable. The one behind the other and / or offset Columns 31, 32, 33, 34 arranged in relation to one another are analogous to the arrangement according to FIG. 2 in groups in the upper one and lower rudder half on both sides of the leading edge 11 summarized and thus allow an individual Control of the liquid and / or gaseous medium.

The distance of the outlet openings 3 from the leading edge 11 of the rudder blade 1 varies depending on the thrust load of the propeller. With this in mind, too several outlet openings at different distances arranged to the leading edge 11 of the rudder blade 1 and each via separate pipes with the conveyor 5 get connected. By arranging throttle valves in the individual medium lines 41, 42 can the pressure conditions and thus the exit speed of the liquid and / or gaseous medium in the different Outlet openings 31 to 34 fixed or variable become.

There is also the possibility that in different Distances to the leading edge 11 of the rudder blade 1 are arranged Outlet openings 3 through individual conveyors to control, the pressure side is individually controllable. This can depend on the rudder position and the rudder deflection to port or starboard in the respective suction side of the rudder blade 1 over the Outlet openings 3 the liquid and / or gaseous Medium with a predeterminable or variable exit speed be blown out to be effective in this way to avoid a suction side tear.

In the normal position of the rudder can blow out of the liquid and / or gaseous medium cavitation phenomena be avoided or reduced, that is by forming a gaseous or liquid haze in the outer skin of the rudder becomes the surface resistance reduced and thus the resistance component of the Rudder lowered. In the same way, a propulsion improvement by blowing out on both sides of the rudder be achieved.

By asymmetrically blowing out the liquid and / or gaseous medium on the upper and lower half of the Rudder, for example by blowing out the liquid and / or gaseous medium on the upper starboard side and the lower port side of the rudder can be under Considering the propeller twist another improvement propulsion and cavitation security Reduced drag on the rudder become.

Figure 4 shows a schematic perspective side view an alternative arrangement of the thruster according to the invention, where the conveyor is not in rudder blade 1, but outside the rudder blade, for example in Rudder engine room is arranged. The supply of the gaseous or liquid medium takes place, for example, via a Bore 20 in the rudder shaft 2 to a medium line 43, the is divided into a plurality of medium lines 44, 45 which lead to the Outlet openings 31 to 34 on the two side surfaces 12, 13 of the rudder blade 1 lead and, for example, in groups in outlet openings 31 to 34 in the upper and lower rudder half are summarized. Figure 4 shows the both to the outlet opening groups 31, 33 in the rudder surface 12 arranged above and below the rudder blade center Outlet openings 31 and 33 leading medium lines 44, 45.

When using a gaseous medium, for example Air, the air supply can in the arrangement according to Figure 4 from outside the rudder blade, for example from the Rowing machine room. The supply of the necessary Air to the outlet openings can also through the Rudder shaft 2 or the koker to the medium lines 44, 45 respectively.

In addition to a change in the exit speed of the liquid and / or gaseous medium by change the delivery rate is a changeable setting of the Outlet openings possible. Figure 5 shows in a cross section through the front part of a rudder blade 1 Anchor or rudder head 10, on which the rudder side surfaces Connect 12, 13. In the transition area from the rudder head 10 to the side surfaces 12, 13 become outlet openings 35, 36 formed by opening cylinders 61, 62 in via a connecting device 6 at a predetermined distance to be arranged to each other.

As a result of those adjacent to the outlet openings 35, 36 Profiling of the rudder head 10 in connection with the cylinder surface can the medium in the direction indicated by arrows Enter the direction in the opening area and out of the Exit openings 35, 36 emerge in such a way that the Flow is applied to the side surfaces 12, 13. In the simplest In this case, the connecting device 6 consists of a bulkhead or one or more spacers that the setting of the exit gaps 35, 36 in both side surfaces 12, 13 of the rudder blade 1 serve.

In contrast, FIG. 6 shows a variant in which an adjusting device 7 the distance between the cylinders 61, 62 to each other through a variable-length connecting device 60 can be set. That way the cross section of the outlet openings 35, 36 varies and be adapted to the respective operating conditions. Depending on Rudder deflection can be on the port or starboard side Outlet openings 35, 36 are opened or closed and in the normal position of the rudder blade 1, both outlet openings can 35, 36 are opened to improve propulsion and to help prevent cavitation.

Figure 7 shows a variant in which the exit column 35, 36 and the two side surfaces 12, 13 of the rudder blade 1 fixed using a special setting device can be. In this embodiment are also Exit cylinders 61, 62 are provided, which have a spacer 60 are connected. An anchor head 100 has a bore 101 for receiving a bolt 8 on, which can be connected to a bolt receptacle 102. Of the Gap S between the anchor head 100 and the bolt receptacle 102 can be varied by means of the bolt 8 so that a different gap size for the exit gap 35, 36 is adjustable. The opening 101 in the anchor head 100 can after the fixed setting of the gap S, that is after installation of the anchor head are filled, so that an uninterrupted, smooth leading edge of the rudder blade 1 is given.

In addition to the options for change described above or setting the exit speed of the liquid and / or gaseous medium and for adjustment and changes in the outlet cross section are further Variants possible. For example, several exit gaps in the longitudinal direction of the rudder one behind the other Devices according to Figures 5 to 7 are provided. Also a combination of changing the exit speed of the liquid and / or gaseous medium Change in pump pressure and a change in Outlet cross section is within the scope of the present Invention. You can do this by using different Pumps for the grouped outlet openings individual control over the entire surface the rudder side surfaces 12, 13 are provided. By a distributed arrangement of outlet openings over the Rudder side surfaces is in particular a reduction or Avoidance of cavitation on the rudder blade It is possible to blow out at the endangered places on the rudder.

Figure 8 illustrates in a diagram that with the invention Solution compared to conventional rowing or Benefits of high-performance rowing.

FIG. 8 shows the course of the coefficients c _{l of} the rudder transverse force (LIFT) and of the drag coefficient c _{d of} the rudder longitudinal force (DRAG) as a function of the rudder deflection for different rudder types. The rudder transverse force is: LIFT = c l * rho / 2 * v * AR and the rudder longitudinal force to: DRAG = c d * rho / 2 * v * AR where c _l and c _{d are} the coefficients of the rudder lateral force and rudder longitudinal force, rho the rudder height, v the inflow velocity, AR is the effective rudder area and the product v ² * AR represents the dynamic pressure.

The coefficients c _l and c _{d shown} for a normal rudder NR, a high-performance fin rudder FR, a rotor rudder RR and a jet rudder SRA illustrate the effectiveness of the solution according to the invention. While the rudder force coefficient c _l for a normal rudder NR and a high-performance fin rudder FR reaches a maximum value of 1.0 or 1.6 with a rudder deflection of 25 ° or 28 ° and then drops exponentially due to the suction side tear, the rudder force coefficient c _{l shows} for a rotor rudder RR an increase up to a maximum of 1.6 with a rudder deflection of approx. 50 ° and then a linear decrease.

In contrast, the rudder lateral force coefficient c _{l increases} with a thruster SRA to a first maximum value of approx. 2.0 with a rudder deflection of approx. 30 ° with a further increase up to a second maximum of approx. 2.2 with a rudder deflection of approx. 45 ° to then drop linearly to a value of 1.0 with a rudder deflection of 70 °. This graph shows that in the main working area of a rudder with a rudder angle of 45 °, the thruster SRA generates a maximum lateral force component that is well above the maximum values of the conventional rudders.

In comparison to this, the rudder longitudinal force coefficient c _{d is entered} for a normal rudder NR and a rotor rudder RR, the rudder longitudinal force coefficient increasing with increasing rudder position.

Claims (22)

Rudder for watercraft with a rudder blade, which has a leading edge or rudder head and adjoining, spaced-apart side surfaces,
characterized by
that outlet openings (3; 31 to 36) for a liquid and / or gaseous medium are arranged in the side surfaces (12, 13) of the rudder blade (1). Rudder according to claim 1, characterized in that the outlet openings (3; 31 to 36) are arranged on the front third of the rudder blade (1) in the direction of travel of the watercraft. Rudder according to claim 2, characterized in that further outlet openings (3; 31 to 36) are arranged distributed over the side surfaces (12, 13) of the rudder blade (1). Rudder according to at least one of the preceding claims, characterized in that a plurality of outlet openings (3; 31 to 36) are arranged one behind the other and / or offset from one another in the direction of travel of the watercraft. Rudder according to at least one of the preceding claims, characterized in that a plurality of outlet openings (3; 31 to 36) are arranged distributed at least over part of the height of the rudder blade (1). Rudder according to at least one of the preceding claims, characterized in that the outlet openings (3; 31 to 36) consist of slots running perpendicular to the direction of travel of the watercraft. Rudder according to at least one of the preceding claims, characterized in that the cross section of the outlet openings (3; 31 to 36) can be changed. Rudder according to at least one of the preceding claims, characterized in that the exit speed of the medium is variable. Rudder according to at least one of the preceding claims, characterized in that the cross sections of the outlet openings (3; 31 to 36) and / or the outlet speed of the medium on both side surfaces (12, 13) of the rudder blade (1) can be controlled independently of one another. Rudder according to at least one of the preceding claims, characterized in that the outlet of the medium can be controlled differently via the height of the rudder blade (1). Rudder according to claim 10, characterized in that the outlet of the medium on both side surfaces (12, 13) of the rudder blade (1) can be controlled asymmetrically with respect to the vertical axis of the rudder blade (1). Control rudder according to at least one of the preceding claims, characterized in that the outlet speed of the medium can be changed by means of a conveying device (5). Control rudder according to claim 12, characterized in that the conveying device (5) is arranged in the rudder blade (1). Steering rudder according to claim 12, characterized in that the conveying device (5) is arranged in the watercraft and the medium is guided via a line (20) which connects the rudder shaft (2) to the hull of the watercraft (2) and / or koker. Rudder according to at least one of the preceding claims, characterized in that the suction opening (4) for a liquid medium is arranged in the rudder blade (1). Rudder according to claim 15, characterized in that the suction opening (4) is arranged on the leading edge (11) of the rudder blade (1), preferably at the level of the propeller shaft. Rudder according to at least one of the preceding claims, characterized in that the suction opening for a gaseous medium is arranged in or on the hull of the watercraft. Rudder according to at least one of the preceding claims, characterized in that the leading edge (11) of the rudder blade (1) consists of an anchor head (10, 100) which is connected to the rudder body delimited by the side surfaces (12, 13) of the rudder blade (1) is connectable and that the outlet openings (3; 31 to 36) are formed between the end faces of the side surfaces (12, 13) and the side edges of the anchor head (10, 100). Rudder according to Claim 18, characterized in that the size of the outlet openings (3; 31 to 36) can be adjusted by changing the distance between the anchor head (10, 100) and the rudder body. Rudder according to at least one of the preceding claims, characterized in that the rudder blade (1) consists of a profiled rudder body and a curved rudder head and side surfaces (12, 13) converging from the rudder head to a trailing edge (14) of the rudder blade (1) and that Outlet openings (3; 31 to 36) are provided in the region of the side surfaces (12, 13) adjoining the rudder head. Control rudder according to at least one of the preceding claims, characterized in that the control rudder consists of a high-performance fin rudder with a fin rudder blade articulated on the rear edge of a main rudder blade and that outlet openings for a liquid and / or gaseous medium are arranged in the front third of the main rudder blade in the direction of travel of the watercraft are. Control rudder according to claim 21, characterized in that outlet openings for a liquid and / or gaseous medium are arranged in the front third of the fin rudder blade connected to the articulation of the fin rudder blade.

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