JPS604495A - Ship with spherical stern - Google Patents

Abstract

PURPOSE:To utilize the wake flow of a propeller effectively in the maximum by a method wherein the stern of the ship is formed into substantially a gentle spherical form toward the rear direction of a hull and a propeller is arranged behind the stern while a rudder, equipped with wings, is arranged behind the propeller. CONSTITUTION:The propeller 4 is arranged behind the stern part, formed into the gentle spherical form toward the rear direction of the hull 1, and near the center of the sphere of the stern. The bow side of the stern part 8 is extended toward the bow so as to envelope the spherical surface thereof and is covered by the stern planking 14 so as to reduce the flow resistance of the stern. The wings 6, 7 with aerofoil type sections are attached to both left and rignt sides of a rudder post 3 so that the mounting angles thereof are proper to the wake flow of the propeller. According to this method, the rotating energy of the wake flow of the propeller can be increased and recovered by utilizing this type of rudder, therefore, the wake flow of the propeller may be utilized effectively in the maximum for the propelling force of the ship and the output of the propelling engine may be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spherical stern boat that can effectively utilize rotational energy in the wake of a propeller as thrust for a boat.

It is well known that the rudder placed in the wake of the propeller generates the thrust that propels the ship, and various ideas have been proposed to extract as much of this thrust as possible (Japanese Patent Application No. 115519/1983). No. and application number 1987-2
(See No. 4509). And especially Jitsugan 57-245
In No. 09, we clarified the influence that the wake of the ship has on the wake of the propeller, and we are actively trying to use the energy of the wake of the propeller more effectively.

The main point of the above-mentioned proposal is that the flow velocity in the propeller axial direction of the flow behind the hull flowing into the propeller operating surface located at the rear of the hull is normally distributed as shown in Figure 1, and as shown in the figure, the flow velocity varies depending on the location. As shown in Figure 2, the rotational flow (a, b, ... h) of the propeller wake at propeller plane 0 is as follows:
The point is to use the fact that the nominal wake coefficient W (see Figure 1) increases in the large part, that is, the propeller axial flow velocity increases in the small part, to set the position and shape of the blade attached to the rudder to the right. . In the figure, q is the propeller axis, r is the propeller rotation direction, W is the nominal wake coefficient, and W is defined by the ship side Vs and.

The above phenomenon is caused by the flow velocity V of the ship's wake flowing into the propeller surface p.
This is because when × becomes smaller, the propeller load mark rises and the rotational energy contained in the propeller wake increases.
Therefore, by changing the stern shape to reduce Vx, that is, 1-W, the propeller wake can be used more effectively.

The present invention was made based on the above-mentioned considerations, and relates to a spherical stern boat in which a rudder with wings attached to the rear of the stern formed in a gentle, almost spherical shape is arranged. Because it effectively recovers the increased propeller wake rotational energy at the stern, it has the advantage of being able to generate even greater thrust than a ship with a normal stern shape, and reducing the ship's fuel costs. It is.

Embodiments of the present invention will be described below with reference to the drawings. 3 to 6 are explanatory diagrams of an embodiment of the present invention and its operation, and in the figures, reference numeral 1 denotes a hull, 2 a rudder plate, 3 a rudder support member for supporting the rudder plate 2, and 4 is the propeller, 5 is the propeller surface, 1 is the propeller axis, j is the propeller rotation direction, k is the center of the hull, and blades 6 and 7 having streamlined cross sections are stretched laterally on both left and right sides of the rudder support 3. It is attached so that it comes out, and 6
The mounting angle of the blades 6 and 7, that is, the angle between the horizontal direction and the line connecting the leading edge of the blade and the trailing edge of the blade, is set to match the flow behind the propeller.

The propeller 4 is located behind a stern portion 8 that is formed into a gently spherical shape toward the rear of the hull 1 and at the center (1) of the spherical surface.
The bow side of the stern portion 8 has hull shape lines 10, 11, 12 that extend toward the bow so as to envelop the spherical surface, and that gradually change as shown in FIG.
．． 13 and configured to reduce water flow resistance at the stern.

Next, we will explain the operation of the ship. Figure 6 shows an example of a model experiment of a ship with a spherical stern. Since the spherical stern has the effect of increasing the effective wake coefficient We, 1-We (indicated by a solid line!) of the spherical stern is: Normal stern boat 1-
It becomes smaller than We (indicated by the broken line m). Note that the horizontal axis in the figure indicates the field number Fn.

The difference in 1-We directly affects the propeller operating point. In other words, the average speed V× of the wake of the hull flowing into the propeller surface 5
-(1-We)vS decreases and propeller load increases. As a result, the rotational energy contained in the propeller wake increases, the J-energy charge recovered by the wings 6, 7 also increases, and a greater thrust is generated in the wings 6, 7 than in a normal stern boat. At this time, at point 6.7, lift force Ll, +2 is generated in the vertically opposite direction due to the wake of the propeller, and Ll, l-2
The total horizontal component T becomes the thrust and propels the hull 1 (see FIGS. 3 and 4).

Further, since the spherical stern has the effect of making the wake distribution uniform on the propeller surface 5, there is an advantage that the degree of freedom in the blade attachment arrangement is increased.

Note that the present invention is not limited to the above-described embodiments, and may be applied to other gist of the present invention, such as forming the stern into a deformed spherical shape, or applying to a multi-axle ship. Of course, changes can be made to the gods as long as they do not deviate from the above.

The spherical stern boat of the present invention has the above-mentioned configuration. Therefore, it exhibits the following excellent effects.

(1) Since the rudder with wings attached to the rear of the stern, which is formed into a gentle, almost spherical shape, is placed, the rotational energy of the propeller wake can be increased compared to a normal stern boat, and the increased rotational energy can be used to increase the rotational energy of the propeller wake. Since the rudder is used for recovery, the wake of the propeller can be utilized to the maximum extent as propulsive force.

1llii) As a result of the above item (1), the fuel cost of the ship can be reduced or the output of the propulsion engine can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 are both a conventional hull wake distribution diagram and a propeller wake distribution diagram on the surface of a conventional ship's propeller.
5 to 5 show embodiments of the present invention, FIG. 3 is a partial side view of a bulbous stern boat, and FIG.
FIG. 5 is a partial perspective view of the spherical stern boat shown in FIG. 3, and FIG. 6 is a diagram showing the operation of the spherical stern boat shown in FIG. 3. 6- In the figure, 3 indicates the rudder support, 6 and 7 indicate the wings, and 8 indicates the stern part. Patent application Hitoshi Kawajima Harima Heavy Industries Co., Ltd. 7- ('1') uJ

Claims (1)

[Claims] 1) A spherical stern boat characterized by having a stern that is gently shaped in a substantially spherical shape toward the rear of the hull, a propulsion device being disposed behind the stern, and a rudder with a wing attached to the rear of the propulsion type. .