EP1476353B1 - Line design and propulsion system for a directionally stable, seagoing boat with rudder propeller drive system - Google Patents

Abstract

The flow channel between the skegs (2) is wedge-shaped, widening continuously in the downward- and sternward directions, preferably with slight curvature. Sidewalls of the flow channel are least partially plane surfaces, running out into fin-like bridging sections, which include displacement volume for the water. This configuration promotes a channel effect resulting in low ships resistance. It also influences after-flow, with favorable effect on propulsion performance.

Description

The invention relates to a powered by at least two rudder propeller seagoing ship with a hull for transporting payloads or passengers, the rudder propellers are designed as electric rudder propellers (PODS) and the hull mitschiffs has an approximately rectangular cross-section, to which aft flow guide ( Skegs) connect, between which a flow channel is formed.

From the German utility model 29913498.9 is a fast seagoing ship known that has hydrodynamically effective skegs before electric rudder propellers.

It is an object of the invention to further optimize such a ship. In particular, the sea behavior of the ship to be improved and continue to achieve a particularly favorable flow of electric rudder propeller.

The previously known ship has been specially designed for the use of electric rudder propellers, each with a traction and pressure propeller on the rudder propeller and it is a further object of the invention to design such a ship so that it with rudder propellers with only one propeller and also with improved Propulsion efficiency can be operated.

The object is achieved in that the flow channel between the skegs is wedge-shaped with a preferably continuous, slightly curved extension down-aft, wherein the side walls of the flow channel are at least partially formed as flat surfaces and in leaking fins-like webs, which have displacement volumes for the water and wherein the flow channel is designed such that it causes a low ship resistance on its channel effect.

By creating the inventively optimized flow channel between the skegs is advantageously achieved a low flow resistance and a low flow velocity of the electric rudder propellers. This reduces the resistance of the ship when driving through the water and the propulsion efficiency can be increased.

In an embodiment of the invention, it is provided that the skegs are formed as fin-like webs, the displacement volumes of the skegs terminating in rounded back stubs, which run aft without vertical connection to the hull to just before the rudder propeller. Through this design is advantageously achieved that before the rudder propellers by the pressure difference between the inside and the outside of the flow channel results in a flow around the ends of the skegs, which extends in the direction of the flow induced by the propellers. As a result, the flow behavior of the propeller is advantageously improved and evened the flow of water to the propellers.

In a further embodiment of the invention it is provided that the displacement volume of the skegs are arranged substantially on the outside of the fin-like webs. This advantageously results in a low-resistance flow channel between the skegs with a calmed outflow of water at the stern of the ship and in consequence a particularly favorable resistance behavior of the stern of the ship.

In a further embodiment of the invention it is provided that the displacement volume on the outside bead-shaped are formed, wherein the bead is formed such that there is an asymmetric flow and outflow of the water in the direction of rotation of the respective rudder propeller, wherein the thus influenced flow results in a favorable Propellerzströmömung. Thus, the advantageous effect of the calmed outflow of water from the flow channel is supplemented by a rotational movement of the water before the propellers, so that there is an overall advantageous flow of the propeller.

It is further provided that the shape and volume of the flow channel at its outlet in the region of the stub so large and the displacement volume are arranged and dimensioned so that the water flowing around and is directed such that a flow around the stub in the direction of rotation of the respective Rudderpropellers results. Thus, in combination with the asymmetrical design of the displacement volume of the skegs, an advantageous uniform and in particular low-turbulence inflow to the propellers results in a manner advantageous for avoiding cavitation. It does not need to forego the usual acceleration of the stern with its favorable effect in terms of the price stability behavior and on the so-called "slamming" of the ship.

It is further contemplated that the rudder propellers have at least one propeller, which is designed as a high sawtooth propeller and is tuned to the inventively manipulated inflow of water. This results in a further improvement of the low-vibration behavior of the propeller with a minimization of cavitation tendency. In a rudder propeller with two concurrent propellers can be used in the pressure propeller and a conventional propeller.

Furthermore, it is provided that the individual dimensions of the hull and the skegs and their composite dimensions on the Vessel speed are turned off, especially as a result of tank towing attempts. The same applies to the dimensions of the high skew propeller. The individual flow parameters that result at the tail depend, for example, on the size of the ship, the speed of the ship, the roughness of the hull surface and other properties varying from ship to ship. It is therefore understood that for each type of ship different individual dimensions for the hull, the skegs, the flow channel and the propeller must be selected. These vary within the scope of areas that must be investigated and optimized in tow tests and tank tests. Load capacity and the costs involved in the production of the ship also play a role, so that there are a large number of possible variations, of which only limit dimensions can be specified. These are advantageously given as a percentage of the ship's width, the length of the ship, the draft, etc.

In a further embodiment of the invention is further provided that also other individual dimensions of the stern, eg the Aufkimmung and the supernatant on the rudder propeller aft and the dimensions of the skegs, eg the outward position, the length and shape are optimized such that the influence of waves , in particular, the wake from the aft waves on the stern (sea shock) is reduced, preferably as a result of tank trials. For a seagoing ship, it is not only important that the ship's resistance is low, but also that the sea behavior of the ship is good. The sea behavior of the ship comes in particular in a run-up from aft to sea, possibly even when lying in troubled harbors, so that the influence of the aft ship form on the sea behavior must be considered. This is the case according to the invention. It also takes into account the foreship shape, which has a significant effect on the straight-line running of the ship.

To optimize the drive system is also provided that the rudder propellers are equipped with pressure propellers; This ensures that a relatively long calming distance for the water is available before entry into the propeller cross-section. Thus, the drainage vortices formed on the hull can undergo at least partial compensation. The cavitation behavior of the propellers is significantly improved without the need for high skew propellers. In this case, a certain loss of efficiency compared to a draft propeller may have to be taken into account, the downstream flow is directed through the rudder propeller housing, optionally arranged here fins and the shaft of the rudder propeller. This is a matter of cost and flow optimization and is also the subject of tank trials.

The distance between the two rudder propellers is advantageously dimensioned such that the rudder propellers can be pivoted on the one hand independently by 360 degrees, but on the other hand, the skew rider does not become too large. The skegs are arranged in alignment with the rudder propellers. An optimal arrangement results at a distance of the two rudder propellers from 1.1 to 1.3 of the propeller diameter.

Advantageous for the energy consumption when driving straight ahead is the arrangement of a separate small straight-ahead driver, as is the case from the non-prepublished patent application DE 101 59 427.5 can be seen in different variants. Thus, the rudder propellers can always be adjusted in the optimum direction of flow and need not be constantly swiveled for price stabilization. This also results in an energy saving by avoiding the thrust bypass, which is greater than the resistance of the separate rudder. The optimal flow direction of each rudder propeller is depending on the tolerances of the hull, the skegs and the rudder propeller mounting different and is optionally determined advantageous during test drives of the finished ship.

The invention will be clarified in more detail with reference to drawings and a parameter definition, from which further as well as from the dependent claims further, also inventive, details can be seen.

FIG 1

eine beispielhafte Skeg-Ruderpropelleranordnung;

FIG 2

ein Spantverlaufsschema von achtern gesehen mit eingezeichnetem POD entsprechend FIGUR 1;

FIG 3

ein Spantverlaufsschema von vorn;

FIG 4

die Darstellung eines erfindungsgemäßen Strömungskanals an einem Schlepptank-Modell;

FIG 5

das Modell mit dem Strömungskanal entsprechend FIGUR 4 von achtern;

FIG 6

die Skegs von der Seite mit dem Strömungskanal entsprechend den FIGUREN 4 und 5 und

FIG 7

das Prinzip der Anordnungen.

In detail show:

FIG. 1

an exemplary skewing Rudderpropelleranordnung;

FIG. 2

a Spantverlaufsschema seen from aft with marked POD according to FIGURE 1;

FIG. 3

a frame progression scheme from the front;

FIG. 4

the representation of a flow channel according to the invention on a towing tank model;

FIG. 5

the model with the flow channel according to FIGURE 4 from aft;

FIG. 6

the skegs from the side with the flow channel according to the figures 4 and 5 and

FIG. 7

the principle of the arrangements.

In FIGURE 1, the area of the stern is shown in side view in Schiffbaubaulicher manner, in which the electric rudder propeller and the skegs are. 1 denotes a skeg seen from the side, which terminates in the rounded bead 2. 3 denotes an electric rudder propeller; Here, for example, an electric rudder propeller with two propellers 4 and 5 and lateral fins is shown. It is understood that as a rudder propeller with a train or a rudder propeller with a pressure propeller, each with the matching flow guide can be used.

6 designates the design waterline (CWL) and 7 the distance between the end of the Skegwulstes and the traction propeller of the electric Rudderpropellers. This distance is the subject of an optimization process, since on the one hand the propeller 5 has to be pivotable behind the outlet of the bead 2 and on the other hand the distance to the bead 2 should be small.

In order to avoid vibrations and to reduce cavitation, a flow equalization section may be advantageous in some ships. The flow equalization distance is the longest when a POD with a pressure propeller corresponding to the propeller 4 is used. Then, the housing of the electric rudder propeller 3 and the shaft of the electric rudder propeller acts as a flow equalization element.

The electric rudder propeller is advantageously at an angle, e.g. 2 degrees, inclined to the horizontal direction. This angle is designated 8. The ship's end is designated 9; Its length, like the other components at the stern of the ship, depends on the configuration of the stern and thus also on the type of ship.

In FIGURE 2, in which the ship's lines (bulkheads) are shown as seen from aft, 10 indicates a typical former course and 12 the electric rudder propeller visible from the aft. As can be seen, although the center 11 of the rudder propeller, as shown in FIG 1, behind the end of the stub, but is arranged asymmetrically to the displacement volume 15. The rudder propeller itself is arranged at a distance 13 from the ship's center; the length of 13 is about 1.1 times the Propeller diameter 16. The inventive, substantially planar, embodiment of the inside of the flow channel, which is formed between the skegs 1 of FIG. 1, results clearly from the line course in the area 14.

In FIG. 3, which shows the course of the ship's line (frame course) seen from the front, 17 denotes a usual frame course and 18 the course at the bulb, which is arranged on the bow of the ship.

FIGURE 3 essentially shows a conventional ship's course, as is common for stable and low-resistance seagoing ships.

FIGS. 4, 5 and 6 show illustrations of an optimized towed model and depict the lower part of the tail end of the towing model of a relatively fast ferry (28 Kn) with a fuselage intended for receiving motor vehicles and passengers. Such towed models are usually used for identification the optimal hull shapes of ships are used and are well known in the art.

In FIGURE 4, 20 designates the flow channel formed between the skegs 22 with their nearly flat, continuously extending side walls 21. The underside of the ship 23 is just as steady and only slightly curved as the inner side 21 of the flow channel 20th

In FIGURE 5, 25 designates the flow channel between the skegs 26 as seen from the aft, which is located below the apex 24 of the landing 28 of the stern of the ship. The skegs 26 are formed aft sharply finned and terminate in bead-like ends 27, which protrude without support elements on the fin-like parts of the skegs 26. Overall, there is a lot streamlined rear shape with good properties compared to aft rising lakes.

In FIGURE 6, the flow channel between the skegs 30 is designated 29. The fin-like end of the skegs is denoted by 31, the bulge-shaped displacement volume by 33. Behind the skegs 30 is arranged for the purpose of optimization, an exchangeable changeable rear part 32, with which the optimum length and possibly inclination of the ship's stern is determined. The bottom of the ship has an obliquely upward sloping shape, which makes up about 1/3 of the length of the ship. This results in a calm, relatively slow outflow at the stern, which leads to a low ship resistance.

A_sk

Die Querschnittsfläche des Skegs bei der Länge L_{Ask ;} abgesetzt vom hinteren Ende des Skeg. $$0.1*{\mathrm{A}}_0<{\mathrm{A}}_{\mathrm{s}\mathrm{k}}<{\mathrm{A}}_0$$

A₀

Die Propellerkreisfläche $${\mathrm{A}}_0=\mathrm{\pi }*{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">D</figure-callout>}}^2/4=0.7853*{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">D</figure-callout>}}^2$$

A_R

Die projizierte Fläche des Hilfsruders $$0.01*{\mathrm{A}}_0<{\mathrm{A}}_{\mathrm{R}}<0.01*{\mathrm{L}}_{\mathrm{p}\mathrm{p}}*\mathrm{T}$$

L_s

Die Länge des Skeg $$0.20*{\mathrm{L}}_{\mathrm{P}\mathrm{P}}<\mathrm{L}\mathrm{s}<0.45*{\mathrm{L}}_{\mathrm{p}\mathrm{p}}$$

L_Ask

Der Abstand von der Skegspitze bis zum definierten Querschnitt A_sk

L_pod

Die Länge des POD.

d_tran

Der Abstand vom hinteren Lot zum Spiegelheck $$2*{\mathrm{L}}_{\mathrm{p}\mathrm{o}\mathrm{d}}>{\mathrm{d}}_{\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{n}}>{\mathrm{L}}_{\mathrm{p}\mathrm{o}\mathrm{d}}/2$$

d_s

Der Abstand zwischen den Mittellinien der Skegs an ihrer Spitze am hinteren Ende der Skegs $$1.5*\mathrm{D}<{\mathrm{d}}_{\mathrm{s}}<\mathrm{B}-1.5*\mathrm{D}$$

d_ss

Der minimale Abstand zwischen der Mittellinie am Ende des Skegs und der Schiffsseite am Beginn der Aufkimmung des Bilgenradius. $${\mathrm{d}}_{\mathrm{s}\mathrm{s}}>0.75*\mathrm{D}$$

d_h

Der Abstand zwischen dem hinteren Ende des Skegs und dem Punkt des beginnenden Anstiegs der Basislinie des Skeg von der Schiffsbasislinie. $${\mathrm{d}}_{\mathrm{h}}>0.3*{\mathrm{L}}_{\mathrm{A}\mathrm{s}\mathrm{k}}$$

dp

Der Abstand zwischen Propellernabe und hinterem Ende des Skegs. $$0.02*\mathrm{D}<{\mathrm{d}}_{\mathrm{p}}<0.02*{\mathrm{L}}_{\mathrm{p}\mathrm{p}}$$

d_t

Der Propellerfreischlag an der vorderen Propellerebene $${\mathrm{d}}_{\mathrm{t}}>0.15*\mathrm{D}$$

α

Der Winkel zwischen Skeg und der Senkrechten zur Schiffsbasis $$<30\mathrm{°}$$

β

Der Winkel von der Mittellinie POD-Propeller zur Schiffsbasis im Längsschnitt $$\mathrm{\beta }<5\mathrm{°}$$

D

Der Propellerdurchmesser

Lpp

Die Länge zwischen den Loten

B

Die Breite des Schiffes auf Spanten

T

Der Tiefgang des Schiffes auf Spanten

AP

Das hintere Lot

FIG. 7 shows the basic arrangement of the individual components for illustrative purposes. These are forms of representation common in international shipbuilding. The parameter values and their claimed scope are defined mathematically as follows:

A _sk

The cross-sectional area of the skeg at the length L _Ask; set off from the back end of the skeg. $$0.1*{\mathrm{A}}_0<{\mathrm{A}}_{\mathrm{s}\mathrm{k}}<{\mathrm{A}}_0$$

A ₀

The propeller circle area $${\mathrm{A}}_0=\mathrm{\pi }*{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">D</figure-callout>}}^2/4=0.7853*{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="imgf0001.png,imgf0003.png"\; state="\{\{state\}\}">D</figure-callout>}}^2$$

A _R

The projected area of the auxiliary rudder $$\mathrm{12:01}*{\mathrm{A}}_0<{\mathrm{A}}_{\mathrm{R}}<\mathrm{12:01}*{\mathrm{L}}_{\mathrm{p}\mathrm{p}}*\mathrm{T}$$

L _s

The length of the skeg $$\mathrm{12:20}*{\mathrm{L}}_{\mathrm{P}\mathrm{P}}<\mathrm{L}\mathrm{s}<\mathrm{12:45}*{\mathrm{L}}_{\mathrm{p}\mathrm{p}}$$

L _ask

The distance from the tip of the skeg to the defined cross section A _sk

L _pod

The length of the POD.

d _tran

The distance from the rear lot to the mirror tail $$2*{\mathrm{L}}_{\mathrm{p}\mathrm{O}\mathrm{d}}>{\mathrm{d}}_{\mathrm{t}\mathrm{r}\mathrm{a}\mathrm{n}}>{\mathrm{L}}_{\mathrm{p}\mathrm{O}\mathrm{d}}/2$$

d _s

The distance between the midlines of the skegs at their tip at the back of the skegs $$1.5*\mathrm{D}<{\mathrm{d}}_{\mathrm{s}}<\mathrm{B}-1.5*\mathrm{D}$$

d _ss

The minimum distance between the centerline at the end of the skeg and the ship's side at the beginning of the bilge radius. $${\mathrm{d}}_{\mathrm{s}\mathrm{s}}>0.75*\mathrm{D}$$

d _h

The distance between the trailing end of the skeg and the point of incipient rise of the baseline of the skeg from the ship's baseline. $${\mathrm{d}}_{\mathrm{H}}>0.3*{\mathrm{L}}_{\mathrm{A}\mathrm{s}\mathrm{k}}$$

dp

The distance between the propeller hub and the rear end of the skeg. $$\mathrm{12:02}*\mathrm{D}<{\mathrm{d}}_{\mathrm{p}}<\mathrm{12:02}*{\mathrm{L}}_{\mathrm{p}\mathrm{p}}$$

d _t

The propeller release at the front propeller level $${\mathrm{d}}_{\mathrm{t}}>\mathrm{12:15}*\mathrm{D}$$

α

The angle between the skeg and the perpendicular to the ship's base $$<30\mathrm{°}$$

β

The angle from the midline POD propeller to the ship's base in longitudinal section $$\mathrm{\beta }<5\mathrm{°}$$

D

The propeller diameter

Ipp

The length between the solders

B

The width of the ship on frames

T

The draft of the ship on frames

AP

The back lot

To the construction according to the invention, which leads to an overall very low ship resistance with good propulsion efficiency of the electric rudder propeller, the rudder propellers, the skegs and the stern shape are interconnected elements acting. The electric rudder propellers are arranged in the outflow of the skegs, that the axis of rotation of the propeller coincides within the region with a significantly reduced axial component of the velocity field. The fact that the electric rudder propellers are arranged behind the skegs, an operation of the propeller in the outflow field of the skegs is made possible. The shaped flow channel leads the outflowing water advantageously directed to the propellers. The lateral display of the skegs and the shape of the flow guide influences the velocity field within the propeller disks such that the tangential components of the velocity field advantageously extend favorably into the propeller. As a result, there is an increase in the efficiency of the propulsion system with reduced cavitation and reduced vibrations. In addition, the skegs result in a higher price stability of the ship. The end result is a significant fuel savings.

This can also contribute to the use of an auxiliary rudder, which allows to set the electric rudder propeller always optimal for outflow in the skeg region. This optimal position need not be changed by course correction movements.

Claims (14)

1. Sea-going marine vessel which is propelled by at least two steering propellers (3) and has a hull for transporting cargoes or passengers, with the steering propellers (3) preferably being in the form of electrical steering propellers (PODS), and with the hull having an approximately rectangular cross section midmarine vessels, adjacent to which, toward the stern, there are flow guide bodies (skegs) (26), between which a flow channel (20) is formed, characterized in that the flow channel (20) is wedge-shaped and widens continuously, preferably with slight curvature, toward the area under the stern, with the side walls (21) of the flow channel (20) being at least partially in the form of planar surfaces and running into fin-like webs (31) which have displacement volumes for the water, and with the channel effect of the flow channel (20) producing low marine vessel drag, and having an influence on the wake which is advantageous for the propulsion response.
2. Marine vessel according to Claim 1, characterized in that the skegs (26) are in the form of fin-like webs (31), with the displacement volumes of the skegs (26) running into stubs which, toward the stern, run to a point shortly in front of the steering propellers (3), without any vertical connection to the hull.
3. Marine vessel according to Claim 1 or 2, characterized in that the displacement volumes (33) of the skeg (26) are arranged essentially on the outside of the fin-like webs.
4. Marine vessel according to Claim 1, 2 or 3, characterized in that the displacement volumes (33) are in the form of beads on the outside, with the bead being shaped such that the water flows around and away asymmetrically in the same rotation direction as the respective steering propeller, in order that the flow that is influenced in this way has an advantageous effect on the flow to the propeller.
5. Marine vessel according to Claims 1, 2, 3 or 4, characterized in that the bottom of the marine vessel has a rise which starts approximately at the start of the flow guide channel (20).
6. Marine vessel according to one or more of the preceding claims, characterized in that the shape and volume of the flow channel (20) at its outlet in the area of the stub are sufficiently large and the displacement volumes are arranged and are dimensioned such that the water flowing around and away is directed in such a manner that it flows around the stubs in the same rotation direction as the respective steering propeller (3).
7. Marine vessel according to one or more of the preceding claims, characterized in that the steering propellers (3) have at least one propeller which is in the form of a high-skew propeller (4, 5).
8. Marine vessel according to Claim 7, characterized in that the high-skew propeller (4, 5) is matched to the characteristics of the directed incident water flow such that large pressure fluctuations are avoided and the cavitation response is optimized.
9. Marine vessel according to one or more of the preceding claims, characterized in that the individual dimensions of the marine vessel's hull and of the skegs (26) and their composite dimensions are matched to the speed of the marine vessel, in particular as a result of tank towing trials.
10. Marine vessel according to one or more of the preceding claims, characterized in that the dimensions of the high-skew propeller (4, 5) are optimized for the directed incident flow, in particular as a result of tank trials.
11. Marine vessel according to one or more of the preceding claims, characterized in that the individual dimensions of the stern (9), for example the rise and the projection beyond the steering propellers (3) toward the stern as well as the dimensions, for example the outward positioning, the volume and the shape of the skegs (26), are optimized such that the influence of waves, in particular of waves striking the marine vessel from astern, on the hull (sea impact) is reduced, preferably as a result of tank trials.
12. Marine vessel according to one or more of the preceding claims, characterized in that the electrical steering propellers (3) each have one propeller which is in the form of a pusher propeller.
13. Marine vessel according to one or more of the preceding claims, characterized in that the distance between the steering propellers (3) corresponds to 1.1 to 1.3 times the respective propeller diameter.
14. Marine vessel according to one or more of the preceding claims, characterized in that an auxiliary rudder for guiding the marine vessel straight ahead is arranged at the stern (9) of the marine vessel, in particular in front of the propellers of the steering propellers, and in particular is in the form of a blade rudder.

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