KR101432118B1 - Ship - Google Patents

Abstract

There is provided a ship capable of reducing the amount of ballast water in a light load operation state in a water displacement type vessel that runs on water.

[Solution]

1. A displacement type watercraft (1) traveling on water, comprising a propeller (10) having 7 or more to 10 or fewer blades (Np), and a propeller Is structured as a position where the multi-wing propeller (10) is completely immersed in water when the waterline (ds) of the watercraft is operated at a planned speed in a lightly traveling state, and a stern tunnel (20) is formed at the stern And the multi-blade propeller (10) is arranged in the stern tunnel (20).

Displacement type vessel

Description

Ship {SHIP}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a ship in which the amount of ballast water is reduced in a lightly-traveling state, in a water-displacement vessel that runs on water.

For large vessels such as tankers and bulk carriers, it is necessary to maintain the appropriate depth of draft during loading and handling of the ballast water in order to maintain good operating conditions under light conditions, So that the strength of the hull is not deteriorated. In particular, it is important that the propeller and ship's stern at the stern are exposed on the water surface so that the propeller will not absorb air, cause cavitation, or deteriorate adjustability.

This ballast water is discharged from the second sea area which is loaded in the ballast tank and the dock of the ship in the first sea area which becomes the light condition, and becomes full after the sail in the light condition. As a result, the sea water as the ballast water is carried from the first sea area to the second sea area, and the underwater living creatures of the first sea area contained in the ballast water are also carried to the second sea area. As a result, there arises a problem of environmental destruction that the second sea area is contaminated by the sea creatures included in the ballast water.

As a countermeasure against this, when the shape of the bottom of the ship from the bow to the stern is viewed in a section perpendicular to the longitudinal direction of the bottom of the ship (transverse section), a shape tapering toward the center of the bottom width And a V-shaped cross section in which the bottom surface of the bottom has a straight line extending from the center in the bottom width direction to both ends thereof (see, for example, Patent Document 1).

However, in such a special type of ship, it is necessary to perform a large number of calculations such as structural calculation, stability calculation, hull shake calculation, maneuverability calculation, numerical analysis of the flow field around the hull and water tank experiment, Because it is a large transportation ship, there is a problem that it is difficult to dry it with a drying facility such as a dock in the present state.

On the other hand, if the number of propeller blades is increased, it is known that the propeller diameter required to obtain the same propulsive force becomes smaller as shown in Fig. FIG. 3 is a graph showing the relationship between the diameter of the bulk carrier and the diameter of the bulk carrier with respect to the bulk carrier of 182 m in length on the Wageningen B screw chart (Report No. W13011-1-RD Wageningen B-Screw-Series: Open Water, Bp1-1 / J and Bp2-1 / small scale): January 1978 NSP (NEDERLANDS SCHEEPSBOUWKUNDIG PROFESSATION)).

This multi-wing propeller has been used in the prior art because it reduces cavitation and flow noise caused by the propeller in special ships such as submarines and high-speed boats, For example, in the case of a ship of a displacement type that sails on the water, because of the reasons such as a high cost and a bad quality.

It is also known that it is possible to raise the water level at the propeller position by installing a stern tunnel. For example, regardless of ballast water reduction (low reduction), a propeller with a large diameter of a low rotation type is required to have a water flow along the bottom of the ship at the top of the stern propeller A tunnel-like guide surface having a cross-sectional shape curved in an upward direction and extending in the fore-and-aft direction is provided so as to guide the tunnel-like guide surface, and both lower positions of the tunnel-shaped guide surface at the position of the propeller The stern tunnel is set up at a level 0.6 to 0.7 times the radius of the propeller circle on the center line of the propeller shaft so that the upper part of the propeller is covered so that the propeller with the large diameter of the stern is kept in the water- tunnel stern) is proposed (for example, refer to Patent Document 2).

[Patent Document 1] JP-A-2003-104279

[Patent Document 2] JP-A-09-240569

The present invention has been made to solve the above problems by paying attention to the relationship between the increase in the number of blades of the multi-blade propeller and the reduction in diameter and the effect of the stern tunnel, and its object is to provide a water- Which is capable of reducing the amount of ballast water in a state of light traveling.

In order to achieve the above object, the present invention provides a water displacement vessel for loading ballast water in accordance with a loading state when traveling on water, wherein the water vessel length (Lpp) is 150 m or more and 350 m or less The propeller is composed of a propeller having 7 or more and 10 or less blades and the stern water line in a light load condition is set as a plan speed in a light load condition, , A stern tunnel is formed at the stern, and a stern SS 3, and the shape of the tunnel increases as the stern is turned toward the stern. At the tip position of the multi-blade propeller in the length direction of the hull, the top of the tunnel has a stern light draft of 0.1 And the projecting portion protruding outward from the lower side of the hull is provided on both sides of the tunnel shape to form the projecting portion, Load ballast water.

The position where all the wing propellers are locked at this time means that the wing propellers do not need to be completely locked when the hull is stopped (zero speed of the ship) The tip of the multi-blade propeller may be immersed in water.

Increasing the number of blades of the propeller reduces the propeller diameter required to obtain the same propulsion force, so that the propeller can be soaked in water so that the water line of the stern can be made shallower. As a result, the amount of ballast water in the light-running state is reduced.

In the above ships, a stern tunnel is formed at the stern and the multi-blade propeller is disposed in the stern tunnel.

With this configuration, the water flow introduced into the stern tunnel can be guided to the upper portion of the propeller, and it is possible to raise the water surface in the stern tunnel substantially above the water surface in the absence of the stern tunnel. As a result, even if the stern draft in the light state is made shallower, a sufficient propeller submerged state can be realized, so that the ballast water can be further reduced.

Further, in the case where the length of the ship (length of the vertical line) Lpp of the ship is not less than 150 m and not more than 350 m, there are many offshore vessels at these ship types and Hangul speed. In addition, since ballast water is often mounted or drained, it is more effective.

According to the ship of the present invention, in a ship on which a ballast water is loaded according to the state of the ship loaded on the water, the number of blades is 7 or more and 10 or less, preferably 8 or more and 10 or less, Since the propeller is constituted as a propeller and the stern water line in the lightly traveling state is constructed as a position where the multi-blade propeller is completely submerged when the air is navigated, the propeller diameter can be made small and the stern water line can be made shallow, Can be reduced.

In addition, when the multi-blade propeller is disposed in the stern tunnel, since the water flow introduced into the stern tunnel can be guided to the upper portion of the propeller, the stern draft in the light state is made shallower to further reduce the ballast water .

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a ship according to the present invention will be described with reference to the drawings. The ship 1 to be an object of the present invention is a ship that sails on water.

First, a description will be given of a ship 1 which is a reference of the present invention. 1 and 2, the ship 1 has seven or more wings at the stern, preferably eight or more wings (eight wings in FIG. 1) Adopt a wing propeller (10). By increasing the number of blades Np, it is possible to reduce the diameter Dp of the propeller in order to obtain the same propulsive force as shown in Fig. It is preferable to increase the number of wings Np in order to obtain a light load ds at a shallow aft because the propeller diameter Dp can be made smaller as the wing number Np is increased. As the ball breaks, the number of wings of about 10 is the practical limit.

According to this ship 1, the number Np of blades of the propeller 10 is increased to 7 to 10, preferably 8 to 10, so that in the generation of the same propulsive force, three to five blades It is possible to make the propeller diameter Dp smaller than that of the propeller having a smaller number of blades Np. Therefore, the stern light draft ds is made smaller than that of the ship 1X (Figs. 7 and 8) which employs the propeller 10X having a smaller number of blades Np than the ship 1 adopting the blades propeller 10 It is possible to reduce the amount of ballast water required for the light-duty operation state. In addition, if the amount of ballast water can be reduced, fuel consumption can be improved because the driving force required for navigation is also reduced.

Next, the ship 1A and the ship 1B according to the embodiments of the present invention will be described. As shown in Figs. 4, 5, and 6, in the ships 1A and 1B, a stern tunnel 20 is also provided and a multi-blade propeller 10 is disposed inside the stern tunnel 20 .

In the stern tunnel 20, a portion where the multi-blade propeller 10 is disposed, in other words, a portion of the ship center line CL is formed in the shape of a tunnel rearward at about the SS (Steer Station) 3, And the peak Pt of the tunnel is located at the upper side of the stern light draft ds at the tip of the propeller of the multi-blade propeller 10 in the longitudinal direction of the hull, (ht) of 0.1 times to 0.5 times as large as the height (ds). On both sides forming the tunnel shape, a projecting portion 21 protruding outward is provided below the hulls 1Ab and 1Bb, and ballast water is loaded on the projecting portion 21 . By providing the projecting portion 21, it is possible to load the ballast water on the projecting portion 21 in addition to the stern tunnel effect by the tunnel fin. The projecting portion 21 is formed in a smooth curve in the ship 1A of Fig. 5, but is formed in a triangle shape in a straight line in the ship 1B of Fig.

In the propeller tip position Xp of the multi-blade propeller 10 in the longitudinal direction of the hull, the lowermost end Pb of the stern tunnel 20 has a stern light draft ds lower than the stern light draft ds 0.1 to 0.5 times the height (hb). The distance Lb between the lowermost ends Pb of the stern tunnel 20 is set to be 0.7 to 3.5 times the diameter Dp of the multi-blade propeller 10. With this configuration, the flow of water in the stern tunnel 20 is efficiently guided to the upper portion of the multi-blade propeller 10, thereby ensuring that the multi-blade propeller 10 is fully locked.

The ship 1 A and the ship 1 B can guide the water flow introduced into the stern tunnel 20 to the upper portion of the propeller 10 so that the water surface in the stern tunnel 20 is substantially guided to the stern tunnel 20, It is possible to raise the water level in the absence of the water surface. As a result, even if the stern draft ds in the light state is made shallower, the state in which the propeller is immersed in water can be realized, so that the ballast water can be further reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view showing a hull rear part of a ship to which the present invention refers; Fig.

Fig. 2 is a side view showing the hull rear part of the ship of Fig. 1; Fig.

3 is a view showing the relationship between the propeller blade number and the propeller diameter.

Fig. 4 is a front view showing the hull rear part of a ship according to the embodiment of the present invention. Fig.

Fig. 5 is a side view showing the hull rear portion of the ship of Fig. 4; Fig.

Fig. 6 is a frontal view showing a hull rear portion of another ship according to the embodiment of the present invention. Fig.

Fig. 7 is a front view showing the rear part of the hull of the ship in the prior art; Fig.

Fig. 8 is a side view of the hull rear portion of the ship of Fig. 7; Fig.

Description of the Related Art

1, 1A, 1B, 1X vessel

10 multi-wing propellers

10X Propeller

20 Stern Tunnel

21 Extension section

A. P. Stern repair line

B. L. Baseline

ds Stiff draft water

Np Propeller Number of Wings

Dp Propeller diameter

Xe stern rear end

Xp Propeller tip (tip) position of the multi-wing propeller in the longitudinal direction of the hull

Claims (3)

(Np) of vessels having a water depth of not less than 150m and not more than 350m in a ship whose water level is to be loaded with ballast water according to the loading condition when it is traveling on water. The propeller is constituted by 7 or more and 10 or less wing propellers 10 and the stern water line in the light load operation state is set to the above The stern tunnel (20) is formed at the stern, and the stern SS 3, the tunnel shape increases toward the stern. In the tip position Xp of the multi-blade propeller 10 in the length direction of the hull, the top Pt of the tunnel is located at the sternight Is formed so as to be 0.1 to 0.5 times the height of the stern light draft above the draft (ds), and the multi-blade propeller (20) is disposed in the stern tunnel (20) (21) protruding outward from the lower side of the hull, and ballast water is loaded on the projecting portion. delete delete

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