JPS6033713B2 - How to install reaction fins at the stern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for attaching a reaction fin provided in front of a screw propeller.

Generally, a rotational flow remains behind the screw propeller on a large ship in the same direction as the propeller's rotation, but a reaction fin can be provided in front of the propeller to provide a rotational flow in the opposite direction to the rotational flow behind the propeller. For example, the rotational energy in the wake of the propeller is reduced, and the propulsion efficiency can be increased by that amount. As such reaction fins disposed in front of the propeller, there are those shown in FIGS. 1 and 2 in the case of a single ship.

In FIGS. 1 and 2, reference numeral a indicates the hull, b indicates the reaction fin, c indicates the stern frame boss as a propeller shaft penetrating portion, d indicates the propeller, and e indicates the rudder.

By the way, when installing action fin b like this on an existing ship, if it is directly welded to the stern frame boss c of the existing ship, the existing stern frame boss c will be distorted by the heat during welding, and the shaft system alignment will be significantly affected. This may cause the stern frame boss c to be re-bored or cause a crack in the stern frame.

In addition, in order to obtain the adhesion of action fin b, it is necessary to
It is necessary to build up nearly 100 layers of weld beads, and it takes an enormous amount of time to attach the reaction fins b, resulting in a problem in that the work efficiency is significantly reduced.

The present invention aims to solve these problems.
To enable efficient attachment of reaction fins at the stern of a ship and to provide a method for attaching action fins.

For this reason, the method for attaching reaction fins to the stern of the present invention is to create a star-shaped section with a plurality of reaction fins arranged radially around the outer periphery of an annular boss, and then attach the annular boss of this star-shaped section to the stern of the ship.

It is characterized in that it is competitively fixed to the outer periphery of the stern frame boss as the cutter shaft penetrating portion. The method for attaching reaction fins at the stern as an embodiment of the present invention will be explained below with reference to the drawings. Fig. 3 is a perspective view showing the state in which the installation work is completed by this method, and Fig. 4 a to c are all the same. A perspective view showing the installation process, and FIGS. 4 d and 4 e are both horizontal sectional views showing the process of fixing the annular post of the star-shaped member to the outer periphery of the stern frame boss, and in each figure, Reference numeral 1 indicates an annular boss as a reaction fin boss, 2 indicates a central reaction fin fixed to the hull 5, 3 indicates a reaction fin other than the central reaction fin 2, and 4 indicates a stern frame boss as a propeller shaft penetrating portion of the hull 5. are shown respectively.

Although the screw propeller is not shown in Figures 3 and 4, this propeller has two reaction fins.
, 3.

Next, to explain how to attach the reaction fins 2 and 3 at the stern of the ship, first, as shown in FIG. 4a, a plurality of reaction fins 3 and an annular boss 1 are manufactured in advance on land as an integral unit.

That is, a star-shaped member S is made in which a plurality of reaction fins 3 are provided radially around the outer periphery of the annular boss 1. The annular boss 1 of this star-shaped member S is then iron-fitted onto the outer periphery of the stern frame boss 4 at the stern of an existing ship from which the propeller, rudder and propeller shaft have been removed, as shown in FIG. 4a. At this time, the outer periphery of the stern frame boss 4 is shaped in advance to fit the annular boss 1, or vice versa, the inner surface of the annular boss 1 is shaped to fit the stern frame boss 4.

The state in which it is attached in this manner is shown in FIG. 4b.

Next, as shown in FIG. 4c, both the upper and lower central reaction fins 2, 2 are fixed to the hull 5 and the annular boss 1. Note that the central reaction fin 2 fixed to the hull 5 may be made of a steel plate, which not only has the original reaction fin effect but also works on the reaction fin 2.
It also has the function of stopping rotational force.

Furthermore, in order to stop the rotational force of the reaction fins 2 and 3, a dowel pin 6 is driven between the annular boss 1 and the existing stern frame boss 4, as shown in FIG. 4d.
Joint part 7 between annular boss 1 and existing stern frame boss 4
to weld.

Finally, as shown in FIG. 4e, in order to correct the level difference at the front end of the annular boss 1, the rectifier nave 8 is attached.

In addition, in the above-mentioned embodiment, the star-shaped member S was fixed to the stern frame boss 4 of the existing ship, but
Of course, the star-shaped member S to the stern frame boss 4 of the new ship
It is also possible to fix it with iron alloy.

As detailed above, according to the method for attaching reaction fins at the stern of the present invention, a star-shaped member having a plurality of reaction fins arranged radially around the outer periphery of an annular boss is created,
Next, the annular boss of this star-shaped member is fixed to the outer periphery of the stern frame boss, which is the propeller shaft penetrating part of the hull, so that the stern frame boss is not affected by heat at all, and the installation time is reduced. This provides the advantage of achieving significant shortening.

[Brief explanation of drawings]

Figures 1 and 2 show conventional reaction fin attachment means at the stern, with Figure 1 being a side view of the stern showing the attached state, and Figure 2 being a sectional view taken along the low 0 line in Figure 1. 3 and 4 show a method for attaching reaction fins at the stern as an embodiment of the present invention, and FIG. 3 is a perspective view showing a state in which the attachment work is completed by this method;
Figures 4 a to c are perspective views showing the installation process, and Figures 4 d and e are horizontal views showing the process of fixing the annular boss of the star-shaped member to the outer periphery of the stern frame boss. FIG. 1... Annular boss, 2... Central reaction fin, 3... Reaction fin, 4... Stern frame boss, 5... Hull, 6... Dowel pin,
7... Joint portion between annular boss 1 and stern frame boss 4, 8... Rectifier cover, S...
Star-shaped member. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Making a star-shaped member with a plurality of reaction fins arranged radially around the outer periphery of the annular boss, and then fitting and fixing the annular boss of this star-shaped member to the outer periphery of the stern frame boss that serves as the propeller shaft penetration part of the hull. A method for attaching a reaction fin at the stern, which is characterized by: