JPH053439Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field of the Invention This invention relates to a rudder for an ice-sea vessel that is provided behind a propeller duct that is provided at the stern of the ice-sea vessel so as to surround a screw propeller.

BACKGROUND OF THE INVENTION Ice-sea vessels are often provided with a cylindrical propeller duct to protect the propeller and improve propulsion efficiency. The rudder is then installed behind the propeller duct.

Problems to be Solved by the Invention When a ship is moving backwards in an ice sea, pieces of ice may flow into the duct from behind or may stick to the rear end of the duct. For this reason, there are problems such as the propeller being damaged or the propulsion force being reduced when moving backward.

The object of this invention is to provide a rudder for an ice-water vessel that can prevent the propeller from being damaged or the propulsion force from decreasing when moving backward.

Means for Solving the Problems This invention is a rudder for ice-sea ships that is installed behind a propeller duct that is installed at the stern of an ice-sea ship so as to surround a screw propeller. The propeller protection fins are characterized in that the rear portion of each propeller protection fin becomes wider as it goes forward.

Function This invention is a rudder for ice-sea vessels that is installed behind a propeller duct that is installed at the stern of an ice-sea vessel so as to surround a screw propeller. Fins are provided, and the rear of each propeller protection fin is formed to become wider as it goes forward, so when the ice ship is moving astern, the screw propeller can be pulled from the rear of the ice ship's rudder by the suction flow of the screw propeller. Ice chips flowing towards the propeller are swept outward from the propeller duct by the propeller protection fins.

Embodiment FIGS. 1 to 3 show an embodiment in which this invention is applied to a one-shaft, one-rudder type ice-sea vessel. A cylindrical propeller duct 3 is provided at the stern 1 of the ice-water vessel so as to surround a screw propeller 2. A rudder for ice-sea ships is provided behind the propeller duct 3, and three horizontally protruding propeller protection fins 5 are provided on both sides of the rudder body 4 at equal intervals in the vertical direction. There is. Each fin 5
is formed into a substantially triangular shape when viewed from above, and from the rear end to the most outwardly protruding apex, the width becomes wider toward the front. The middle fins 5 are formed wider than the upper and lower fins 5. The most outwardly projecting apex of each fin 5 lies on a circumference approximately the same size as the rotational circumference of the screw propeller 2. Each fin 5
In order to reduce water resistance, the vertical cross section along the front-rear direction is preferably formed into a substantially airfoil shape, a substantially oval shape, or the like. In this embodiment, it is formed into a substantially airfoil shape.

When the ice ship is moving backwards, ice chips (not shown) that flow toward the rudder body 4 from the rear toward the screw propeller 2 due to the suction flow of the screw propeller 2 are moved as shown by the arrows in FIG. Then, it is swept outward of the propeller duct 3 by the fins 5 of the rudder body 4. Therefore, it is possible to prevent ice chips from flowing into the propeller duct 3 or from sticking to the rear end of the propeller duct 3. As a result, the screw propeller 2 will not be damaged or the propulsion force will be reduced during backward movement.

The number of propeller protection fins 5 provided on both sides of the rudder body 4 can be determined arbitrarily. Further, the planar shape of the propeller protection fins 5 may be any shape as long as its rear part becomes wider toward the front, and may be substantially triangular or substantially trapezoidal as shown in FIG. 4. . Further, as the propeller protection fins 5, the length of the attachment side to the rudder body 4 may be relatively short compared to the cord length of the rudder body 4, such as the fin 5 shown in FIG. good.

Furthermore, this idea was developed for a two-axle, two-rudder ice-sea ship,
As shown in FIG. 6, it can also be applied to a two-shaft, one-rudder type ice-sea vessel. In FIGS. 4 to 6, parts corresponding to those in FIG. 1 are given the same reference numerals and their explanations will be omitted.

Effects of the invention According to this invention, when an ice-sea vessel is moving astern, ice chips that flow from behind the rudder of the ice-sea vessel toward the screw propeller due to the suction flow of the screw propeller are removed by the propeller protection fin. Since the ice chips are flowed outward from the propeller duct, it is possible to prevent the ice chips from colliding with the screw propeller when moving backward, and it is also possible to prevent the ice chips from sticking to the rear end of the propeller duct. As a result, it is possible to prevent the screw propeller from being damaged and the propulsion force from decreasing when moving backward.

[Brief explanation of the drawing]

Figures 1 to 3 show an example in which this invention is applied to a one-shaft, one-rudder type ice-sea vessel. Figure 1 is a side view, Figure 2 is a rear view, and Figure 3 is a horizontal cross-section. It is a diagram. FIG. 4 and FIG. 5 are plan views showing modified examples of the propeller protection fin, respectively. FIG. 6 is a rear view showing an embodiment in which this invention is applied to a two-axle, one-rudder type ice-sea vessel. 1... Stern, 2... Screw propeller, 3
...Propeller duct, 4...Rudder body, 5...Propeller protection fin.

Claims (1)

[Scope of utility model registration request] A rudder for an ice sea ship is provided behind a propeller duct 3 provided at the stern 1 of the ice sea ship so as to surround a screw propeller 2, and includes propeller protection fins 5 horizontally protruding from both sides of the rudder body 4. A rudder for an ice-water vessel, characterized in that the rear of each propeller protection fin 5 is formed wider toward the front.