JPH0129199Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a water jet propulsion boat suitable as a high-speed boat.

Conventional water jet propulsion vessels include those shown in Figures 1 to 3, in which Figure 1 is a longitudinal cross-sectional view showing its cruising condition, Figure 2 is a longitudinal sectional view showing its high-speed cruising condition, FIG. 3 is a longitudinal sectional view showing the sailing state in waves.

As shown in Fig. 1, in this water jet propulsion ship, seawater is sucked in through an open water inlet 1 opened at the bottom of the ship, and an impeller 3 installed in a duct 1a.
be led to.

The seawater driven by the impeller 3 is jetted rearward as jet water from a water jet propulsion nozzle 1b provided at the stern, thereby propelling the water jet propulsion ship.

In addition, the code|symbol 2 in a figure shows the water surface, and 4 has shown the main engine which operates the impeller 3.

When the water surface 2 is calm, such a water jet propulsion boat enters a high-speed cruising state as shown in FIG. 2, and at that time, the boat body receives an upward force from the water surface 2 and rises to the surface. When the hull floats in this manner, the resistance of the hull from the water is reduced, so that the required horsepower of the main engine 4 can be reduced.

However, in the above-mentioned conventional water jet propulsion boat, there is a risk that air above the water surface 2 will be sucked in from the open water intake port 1 as the boat floats up during high-speed cruising. When such an air suction phenomenon occurs, there are problems such as a decrease in the efficiency of the impeller 3 and a load fluctuation or overspeed of the main engine 4.

In addition, as shown in Fig. 3, when this water jet propulsion vessel travels at high speed in waves, the hull movement due to the waves and the vertical movement of the water surface 2 overlap, causing the open water intake port 1 to drop to the water surface. It may appear above 2. In this state, the suction of water into the duct 1a stops, making it impossible to cruise at high speed and forcing the boat to decelerate.

This invention attempts to solve the above-mentioned problems by preventing air from being sucked in from the open water inlet, while actively inhaling open water from below the bottom of the ship. The purpose of the present invention is to provide a water jet propulsion vessel that can travel at a sufficiently high speed even in waves.

Therefore, the water jet propulsion boat of the present invention has an external water suction section provided at the bottom of the ship, a duct that runs from the external water suction section through the inside of the ship to the stern, and a water jet connected to the rear end of the duct. The external water suction section includes a propulsion nozzle and a water-driving impeller installed in the duct, and the external water suction section has a water suction port that opens on the bottom of the ship, and a water suction port that extends downward along the left and right outer edges of the water suction port. It is characterized by being composed of air suction prevention fins that protrude from the fins, and guide vanes that connect these left and right fins to each other.

Hereinafter, a water jet propulsion boat as an embodiment of the present invention will be explained with reference to the drawings. FIG. 4 is a longitudinal cross-sectional view showing the main parts thereof, FIG. 5 is a cross-sectional view thereof,
FIG. 6 is a cross-sectional view corresponding to FIG. 5 and showing a modification thereof.

As shown in Figures 4 and 5, the water jet propulsion vessel of the present invention has a water suction port 11a formed on the bottom of the ship, and a water suction port 11a that protrudes downward along the left and right outer edges of the water suction port 11a. Fins 5, 5 for preventing air suction are provided.

Guide wings 6 are arranged to connect these left and right fins 5, 5 to each other.

In this way, the water suction port 11a, the fins 5, and the guide vanes 6 constitute the external water suction section 11.

Additionally, there is a duct 1a that passes through the interior of the ship from the open water suction section 11 to the stern section, a water jet propulsion nozzle 1b connected to the rear end of the duct 1a, and the duct 1
A water-driven impeller 3 is mounted inside a.

By the way, when impeller 3 is operating,
Since the pressure near the water suction port 11a is very low compared to the surrounding pressure, if the fins 5, 5 are not provided, even if the water suction port 11a is below the water surface 2, the water suction port 11a will be submerged. If the water depth is shallow, there is a risk that air may be sucked into the duct 1a from above the water surface 2.

In order to prevent this, in the present invention, the fins 5, 5
These fins 5,
5 is suspended to a sufficient depth so as to block the passage of air sucked into the water suction port 11a from the water surface 2. Furthermore, since the passage of air that is about to be sucked into the water suction port 11a exists from both sides of the water suction port 11a to a little forward, the length of the fins 5 is also set to a size that can prevent the air from flowing in. ing.

Further, three guide wings 6 are arranged at a required interval from each other so as to connect the left and right fins 5, 5 and guide water to the water suction port 11a.

In a modified example of the water jet propulsion boat of the present invention shown in FIG. 6, the cross-sectional shape of the guide vanes 6 is curved so as to be convex downward.

Since the water jet propulsion boat of the present invention is constructed as described above, even when the water jet propulsion boat floats up in a high-speed cruising state or traverses at high speed in waves, the fins 5, 5 Since this blocks the passage of air, it is possible to sufficiently prevent air from being sucked into the water suction port 11a.

Moreover, the effect of the guide vanes 6 allows the flow of seawater to be rectified and sent to the water suction port 11a, thereby improving the efficiency of the impeller 3.

Furthermore, since the guide vanes 6 are arranged to connect the left and right fins 5, 5, there is an effect of increasing the strength of the fins 5, 5.

As described in detail above, according to the water jet propulsion boat of the present invention, there is an external water suction section provided at the bottom of the ship, a duct that runs from the external water suction section through the interior of the ship to the stern, and a rear end of the duct. The external water suction section is equipped with a water jet propulsion nozzle connected to the duct, and a water drive impeller installed in the duct. It has a simple structure consisting of air suction prevention fins that protrude downward along the outer edge, and guide vanes that connect these left and right fins to each other, so that the draft is shallow. Even when sailing at high speeds or in waves, the left and right fins prevent air from being sucked into the duct for propulsion of the water jet, thereby avoiding a drop in efficiency and adverse effects on the main engine due to the impeller idling. Furthermore, the guide vanes that connect the left and right fins provide a rectifying effect on the flow toward the impeller, and can also contribute to improving the strength of the fins.

[Brief explanation of drawings]

Figures 1 to 3 show a conventional water jet propulsion vessel. Figure 1 is a longitudinal sectional view showing its running state, Figure 2 is a longitudinal sectional view showing its high-speed running state, and Figure 3 is a longitudinal sectional view showing its high-speed running state. It is a longitudinal cross-sectional view showing the sailing state in waves,
Figures 4 to 6 show a water jet propulsion ship as an embodiment of the present invention. Figure 4 is a longitudinal cross-sectional view showing the main parts, Figure 5 is a cross-sectional view, and Figure 6 is a cross-sectional view of the ship. 5
It is a cross-sectional view showing a modified example corresponding to the figure. 1...Outside water inlet, 1a...Duct, 1b...
Water jet propulsion nozzle, 2... Water surface, 3... Impeller, 4... Main engine, 5... Air suction prevention fin, 6... Guide vane, 11... Outside water suction part, 1
1a...Water suction port.

Claims (1)

[Scope of utility model registration request] An external water intake part provided on the bottom of the ship, a duct running from the external water intake part through the inside of the ship to the stern, and a water jet propulsion nozzle connected to the rear end of the duct,
A water-driving impeller is installed in the duct, and the outside water suction section has a water suction port that opens at the bottom of the ship, and a water suction port that protrudes downward along the left and right outer edges of the water suction port. A water jet propulsion vessel characterized by comprising air suction prevention fins and guide vanes arranged by interconnecting these left and right fins.