JPS5849593A - Small fishing boat - Google Patents

Abstract

PURPOSE:To raise the turning efficiency of a propeller by guiding sea water toward said propeller while inclining a propeller post in the stem direction in a small fishing boat provided with said propeller post on the rear end of a plate shaped hill piece projected on the bottom of the boat. CONSTITUTION:A propeller 12, a steeling plate 13, and a hill piece 14, etc., are provided on the stern part of a hull 11, and a propeller post 15 on the rear end of the hill piece 14. The propeller post 15 is provided while iclined by about 30 to 60, and the cross section thereof approximately forms a right triangle. Accordingly, said cross section apparently presents an acute angle to sea water flowing around said cross section, so that turbulance behind a turbulent flow is remarkably reduced compared with a case where said cross section was formed in a vertical direction against the sea water, allowing the resistance against sailing of the fishing boat is reduced furthermore. Besides, a flow (f) inducing sea water to flow toward the propeller 12 is generated.

Description

[Detailed Description of the Invention] The present invention relates to the structure of a propeller post in a small fishing boat used for whitebait fishing, etc., and is particularly characterized in that the propeller post is formed so as to be inclined toward the bow direction. The point is that the seawater flowing through this part is guided towards the propeller to increase the rotational efficiency of the propeller. There is an upper limit on the horsepower of the pod engine.Therefore, the speed of fishing boats of the same type remains constant.

However, the faster the speed of a fishing boat, the shorter the time it takes to travel to and from the fishing grounds, and the less time it takes to detect schools of fish at the fishing grounds, so the actual operation time becomes longer.
This increases the possibility that the amount of fish caught will increase. For these reasons, it has been desired to increase the overall speed of a fishing boat without changing the hull shape or engine horsepower. We focused on the fact that resistance occurs in the propeller post, and that this reduces the rotational efficiency of the propeller.We improved the propeller post to reduce the resistance to water flow in this part, and developed this product. By guiding seawater toward the propeller, the rotational efficiency of the propeller is increased, thereby increasing the ship's speed.

Here, a general outline of the propeller post will be explained using a conventional all-aluminum whitebait fishing boat as an example.

In Fig. 1, reference numeral 1 indicates a hull, 2 a propeller, 3 a rudder plate, 4 a hill piece, 5 a propeller post, 6 a propeller boss, 7 a sea piece, and 8 a propeller shaft. The propeller boss 6, the propeller boss 5, and the hill piece 4 are integrally formed by an outer plate.) A propeller shaft 8 is supported by the propeller boss 6, and the propeller 2 is attached to this. Further, a sea piece 7 is attached to the lower end of the propeller post 5, and the steering plate 3 is supported by this.

When the fishing boat seen in this way moves to the right in the figure, the seawater along the hill piece 4 flows relatively backward, but as mentioned above, the propeller post 5 is formed vertically, so The seawater creates a turbulent wake in this area, which acts as a strong resistance to the fishing boat's progress (see Figure 2). In addition, the propeller 2 pushes the seawater that enters into it backwards, and uses the reaction force to act as a thrust force that moves the fishing boat forward. Since the above-mentioned turbulent wake affects the propeller 2 from the position immediately after the propeller 2, the speed of the seawater being drawn into the propeller 2 inevitably slows down. , the resistance force against the rotation of the propeller 2 increases, and the speed of the seawater pushed backward by the propeller 2 becomes slower.

In particular, since the propeller shaft 8 and the sea piece 7 sandwich the space between the propeller bost 5 and the propeller 2, seawater will not enter this area from below the shoe piece 7. The effect of wake will be even greater.

Next, the present invention will be specifically explained based on the drawings.
In the figure, numeral 11 is the hull, 12 is the propeller, 131d rudder plate% 14 is the hill piece, 15 is the propeller bust, 16
is the propeller boss, 17 is the shoe piece, 18 is the propeller shaft, and the propeller post 15 is inclined at about 30 to 60 degrees.Other than that, there are almost no changes from the conventional one described above. do not have.

By forming the propeller post 15 at an angle as described above, the present invention has the following effect (4).

First, the propeller bost 15 is a columnar body with a right-angled triangular cross-section, as in the past, but because it is slanted, the cross-sectional shape of the propeller bost 15 is difficult to see for the seawater flowing through this part. The angle becomes an acute angle. (Refer to Figure 4) Therefore, the turbulent wake becomes significantly smaller than if it were formed directly, and as a result, the resistance to the fishing boat's progress is further reduced. Next, the propeller 12 of this turbulent flow
Regarding the influence on the flow, it is natural that the influence is small because the turbulent wake itself is small, but in addition, since the propeller post 15 is inclined, the distance between it and the propeller 12 becomes large, and the The influence becomes even smaller.0 Furthermore, behind the propeller bost 15, a flow f is generated along this flow, and this flow guides the seawater toward the propeller 12.
At the same time, this flow eliminates the turbulent wake. As a result, a relatively fast flow is taken into the propeller 12, and the rotational speed of the propeller increases, increasing the propulsive force.

As detailed above, the present invention is a small fishing boat that has a plate-shaped hill piece protruding from the bottom of the boat and a propeller boss attached to the rear end of the boat, with the propeller boss tilted approximately 30 to 60 degrees. This reduces the turbulent wake caused by the propeller boost and directs seawater toward the propeller.Although the structure is extremely simple, it reduces the drag force of the ship and increases the rotational efficiency of the propeller. 0, which can increase the ship's speed and achieve the specified speed with low output.

[Brief explanation of drawings]

Figure 1 is a side view showing the stern part of a conventional small fishing boat, Figure 2 is a sectional view taken along line A-A of the same as above, Figure 3 is a side view of an embodiment of the present invention, and Figure 4 is B-- It is a sectional view taken along the B line. 11; Hull 12; Propeller 13 i Rudder
Board 14 i Hillpiece 15; Propeller Bost
16 i propeller boss 17; shoe piece 18;
Propeller shaft () Figure 1 Figure 2

Claims (1)

[Claims] In small fishing boats with a plate-shaped hill piece protruding from the bottom and a propeller post attached to the rear end, the propeller boss)
A small fishing boat characterized by being tilted towards the bow by approximately t-30 to 60 degrees