JP2008049988A - High speed fishing boat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ship type for reducing labor, and increasing a speed, by simultaneously realizing a high speed ship type of approaching the buoyancy center backward, by taking in an inclined flat surface being smooth and untwistable in a ship bottom gliding surface over the stern end from the longitudinal center vicinity, while arranging a large skeg, a large propelling propeller and a large rudder being the requirements required for a fishing boat. <P>SOLUTION: A projection part 7 having a triangular cross-sectional shape is bilaterally symmetrically arranged to the hull center line 11. This constitutes buoyancy reaching the stern end from its central vicinity in the longitudinal direction of a hull, and can position the longitudinal center LCB of the buoyancy backward as the whole ship. A knuckle line 8 constituted in front and in rear by the apex 8a of a triangle is formed in a shape near to a straight line together with a chine line 12, and is arranged near to parallel, and thereby, the ship bottom gliding surface 4 over the stern end from the longitudinal center vicinity of the hull, can be formed as an untwistable surface near to a plane. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a ship such as a fishing boat having a large skeg on a keel and a sliding surface capable of high speed traveling at the same time.

Fishing boats vary depending on the type of fish, fishing method, and fishing ground, but when fishing at sea, there are many cases where all boats are stopped or run slowly. The difference with other ship types such as cargo ships and tankers that carry luggage, coast guard boats, pleasure boats, etc. is that they do not run at a fixed speed. The reason why fishing boats have a larger skeg than other vessels is to ensure performance when stopping and running at low speed.

When drawing heavy nets at low speeds, large skegs are effective to reduce cross flow. In many cases, it is necessary to stay at the same spot where the fish are located. In order to stay in the same place without being swept by the tide or wind, the bow must be directed in the same direction, that is, upwind. To that end, the ship side area center (CLR) below the water surface must be on the bow side, and a large skeg must be provided below the water surface.

In addition, this large skeg is necessary to prevent nets and ropes from getting caught in the propeller for propulsion during fishing. Even if a ship rides on a net or rope, the net or rope passes under the skeg extending from the bow to the stern and does not get caught in the propeller for propulsion.

A fishing boat with a large keel-type skeg can be directly elevated on the slope of the port. Even without a shipyard or special overhead equipment, shipowners can raise fishing boats and store them on land on a daily basis. On the other hand, even if it does not have this keel-type skeg, if it has a large skeg, the overhead work becomes much easier than a ship that does not have it at all.

For the above reasons, most fishing boats have a large skeg in the keel. However, this large skeg is not only resistance during running, but also has a fluid effect on the water flow flowing through the propeller and the rudder disposed behind the skeg. Therefore, a ship with a large skeg needs to have a large diameter propeller and a large rudder. This is because a propeller for propulsion having a small diameter with respect to the width and height of the skeg is inefficient, the boat speed is slow, and the fuel consumption is also poor. In addition, small rudder remarkably deteriorates turning performance and hinders fishing.

In order to place a large propeller for propulsion and a large rudder under the draft near the stern, the bottom of the stern cross section must be flat and shallow. For this reason, in the conventional hull form of a fishing boat, it is common that the bottom running surface is twisted from near the center of the hull to the rear end of the stern. Further, since the stern cross-sectional shape is flat and shallow from flooding, the buoyancy on the stern side is less than that on the bow side, and the buoyancy of the entire hull is arranged on the front side compared to other high-speed ships.

On the other hand, the V-shaped hull form used in many recent high-speed boats, such as coast guard boats and pleasure boats that do not require large skegs, has a V-shaped hull cross-section with a deep bottom bottom, near the front and rear center The main feature is that it creates dynamic pressure by running water on the running surface from the stern to the stern end, and moves up. If the hull surface rises and the amount of drainage during the run is apparently reduced, the hull resistance is reduced as a result, and the speed can be increased. Generally, the speed of a ship traveling along the coast is about 0.5 to 2.2 in terms of fluid number. It is about 1.0 to 1.5 for high-speed commercial vessels, and 1.5 to 2.2 for guard boats and police boats. In fishing boats, the number of fluids exceeding 1.3 has increased due to the recent increase in speed.

The faster the ship becomes, that is, the greater the number of fluids, the greater the rate of ascent due to gliding relative to the amount of drainage. When ascending and sailing, the front part of the hull is lifted from the surface of the water, and only the rear part of the hull is submerged below the surface. In order to keep running in this position, stable running is not possible unless the dynamic pressure generated on the running surface of the hull deck and the center of gravity of the ship are balanced. Due to this fact, a ship with a larger fluid number needs to be designed so that the position of the center of gravity of the hull is in the rear side.

The reason why V-shaped hulls are often used for high-speed ships is that the running surface from the front and rear center to the stern end can be made smooth and flat with less twist. In addition, it is easy to design the center of buoyancy rearward by controlling the rabbet line and the chine line.

By the way, in recent years, the fishery has been transformed into an efficient fishery by the progress of fishing equipment. For example, it has become an era when fish in the sea can be seen by fish finder, and it is now possible to fish while checking the fish. In addition, the main engine has been improved in performance due to improved horsepower with respect to weight, size, and volume. On the other hand, the hull part of the fishing boat is maintaining the old shape at present. In order to reduce fishing costs in such an environment, there is a need for a faster modern fishing boat hull form that uses a smaller engine, uses less fuel, and reaches the fishing ground faster if it is a boat of the same size. It has been.

Therefore, the present invention is a necessary requirement for fishing boats, with a large skeg, a large propeller for propulsion, and a large rudder installed. The issue is to provide. However, the present invention can be applied to vessels other than fishing boats having skegs.

In order to solve the above-mentioned problems, the slope that runs from the center of the front and rear to the stern end is smooth and has little torsion, with the large skeg, large propeller, and large rudder that are necessary for the fishing boat installed. It realizes a high-speed hull form that incorporates a flat surface with, and at the same time brings the center of buoyancy back.

Protrusions with a triangular cross-sectional shape are provided on the left and right sides of the hull in the width direction of the hull as far as possible, leaving the propeller part and skeg part of the hull center part in the part from the front and rear center part of the hull to the stern end. If possible, a plane with less torsion is formed as a sliding surface in a portion of 2/3 or more of the width of the hull. The convex portion having a triangular cross-sectional shape becomes 0 near the front and rear central portions, increases gradually toward the rear, and becomes the maximum from the vicinity of the propeller cross section to the vicinity of the stern end. The central section of the hull section with the propeller for propulsion maintains the conventional fishing boat shape from the vicinity of the center of the hull to the stern end. As a result, a large skeg, a large propeller for propulsion, and a large rudder, which are requirements for a fishing boat disposed in the center of the hull cross section, are maintained.

There is a space called propeller aperture from the upper part of the propeller for propulsion to the lower part of the hull. This space is necessary to prevent the propeller vibration from being transmitted to the hull, and it also serves to protect the hull from cavitation. In general, the propeller aperture in a high-speed boat is set between 12% and 25% of the propeller propeller diameter. The distance and the distance from the propeller for propulsion to the convex portion having a right and left triangular cross-sectional shape are set to be approximately the same. This is because if the amount is too small, the above-mentioned adverse effect is exerted on the hull. If the amount is too wide, the area of the ship bottom sliding surface, which is the plane on the ship side having a triangular cross-sectional shape, becomes narrow, and the sliding performance becomes disadvantageous.

The line formed in the front-rear direction by the intersection of the triangular cross-section side of the ship and the triangular cross-section side of the propeller is continuous from the center of the hull front and back to the stern end, and is close to a smooth straight line It is characterized by. If the intersection of the triangular cross-sectional surface on the ship side and the triangular cross-sectional surface on the propeller side is an acute angle, it may cause turbulence and vortices flowing into the propeller, and may be rounded.

Hereinafter, embodiments of the invention according to this application will be described with reference to the drawings. 1A is a side view showing the first embodiment, and FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A. 2A and 2B are cross-sectional views taken along lines BB and CC in FIG. 1A, respectively. 1 and 2 show the hull form of a conventional fishing boat.

As shown in FIG. 1A, the large skeg 1, the large propeller 2 for propulsion, and the large rudder 3 are necessary requirements for the fishing boat, as described in the prior art. These are obstacles to speeding up, and the boat speed increases if the shape is reduced. However, in the embodiment of the present invention, these necessary requirements remain the same as in the prior art, and the bottom sliding surface from the vicinity of the front and rear center of the hull to the stern end forms a smooth flat surface with little twist. B), convex portions 7 having a triangular cross-sectional shape as shown in FIG. 2 are provided symmetrically with respect to the hull center line 11. The area of the convex portion 7 having a triangular cross-sectional shape is 0 in the vicinity of the center of the hull front and rear, and is gradually increased toward the rear of the hull, and is arranged so as to become the maximum from the vicinity of the propeller cross section to the vicinity of the stern end. . The convex section 7 having a triangular cross-sectional shape constitutes buoyancy from the center of the hull to the stern end in the front-rear direction of the hull, and the center of the buoyancy in the front-rear direction (LCB) of the ship as a whole compared to the conventional hull form. Can be located rearward. At the same time, the convex portion 7 having a triangular cross-sectional shape can reduce the twist of the ship bottom running surface 4 and form the ship bottom running surface 4 closer to a flat surface.

In the above-described two points, the embodiment of the present invention can be a high-speed type hull, that is, a planing hull, as compared with a conventional fishing boat hull. According to theoretical ship engineering, the number of fluids for which a sliding hull form is effective is 0.8 or more. It is 15 knots or more for a 10M long ship and 19 knots or more for a 15M long hull. The embodiment of the present invention is not effective in a ship that is slower than this. However, the greater the Froude number, that is, the higher the speed, the greater the effectiveness.

In the case of a uniaxial keel fishing boat, the large skeg 1, the large propeller 2 for propulsion, and the large rudder 3 are arranged near the hull center line 11. Therefore, it is necessary to maintain the conventional shape in the vicinity of the hull center line 11, but in order for the hull to have a greater sliding performance, it is desired to obtain a wider bottom surface 4. If possible, it is ideal to dispose the ship bottom sliding surface 4a at a portion of 2/3 or more of the width of the hull and form the convex portion 7 having a triangular cross-sectional shape. A space called a propeller aperture 13 is required from the upper part of the propeller 2 for propulsion shown in FIG. This space is necessary for maintaining the propeller efficiency alone and not transmitting the propeller vibration to the hull, and also serves to protect the hull from cavitation. In general, the propeller aperture in a high-speed boat is set between 12% and 25% of the propeller propeller diameter. For the same reason, this distance and the distance from the propeller 2 for propulsion or the propeller circle 2a in FIG. 1B to the propeller-side surface 9 constituting the left and right triangular cross-sectional shapes should be the same as the propeller aperture. is there. Thereby, the vertex 8a of the convex part 7 having a triangular cross-sectional shape is determined. The cross section line 4a in FIG. 1 (B) and FIG. 2 constituting the ship bottom sliding surface 4 of FIG. 1 (A) is a line close to a straight line extending from the ship side tine 12b to the vertex 8a of the inner triangle.

1 (B) and FIG. 2 where the triangular vertex 8a continues in the longitudinal direction of the hull, that is, the knuckle line 8 in FIG. 1 (A) is shown in FIG. 1 (B), and the chines 12a and 12b in FIG. Along with the continuous lines, that is, the inline 12 of FIG. 1 (A), from the vicinity of the center of the hull to the rear side, a shape close to a straight line can be used to make the ship bottom running surface 4 close to a plane. Further, by arranging the knuckle line 8 and the chine line 12 in parallel from the center of the hull to the rear side, it is possible to geometrically make the ship bottom running surface 4 a flat surface with little twist.

FIG. 3 shows, as a second embodiment of the present invention, the propeller side surface 9 constituting the triangular cross-sectional shape of the first embodiment and the hull lower portion 5 of the upper portion of the propeller 2 for propulsion are integrated into an arc shape. This is an example of arrangement. Of the convex portions 7 having a triangular cross-sectional shape, the line 4a forms a bottom planing surface 4 that is an inclined surface that is close to a flat surface and less twisted from the vicinity of the center of the hull to the stern end as in the first embodiment.

FIG. 4 shows an example adopted in a uniaxial semi keel ship as a third embodiment of the present invention. Similarly, FIG. 5 shows an example of a uniaxial bracket ship. In both cases, the skeg width can be narrowed because the skeg is smaller than that of a single-axle keel ship. Therefore, since the diameter of the propeller for propulsion can be reduced, the bottom running surface 4 can be widened in the width direction of the hull, and the sliding performance is better than that of the single-shaft keel ship, so that the efficiency can be improved.

In addition, the present invention can be applied not only to a new ship, but can also be applied to a hull of an existing single-shaft main keel ship, single-shaft semi-keel ship, or single-shaft bracket ship as a modification. The conditions for speeding up and energy saving by remodeling are when the center of gravity of the entire ship can be moved backward by the amount of buoyancy that moves backward, and when the hull width is sufficient to ensure that the bottom planing surface is sufficiently wide in the width direction. This is the case for a ship running with a fluid number of 0.8 or more. However, since the weight is expected to be increased by remodeling, the effect as new shipbuilding cannot be expected.

Effects and embodiments of the invention

As described above, in a ship that regularly runs at a ship speed in a sliding area with a fluid number of 0.8 or more, the shape of the bottom sliding surface in the latter half of the hull is a major factor that affects the performance. Ships that run in this state levitate and run due to the dynamic fluid force received from the bottom of the ship. As the number of fluids increases, that is, as the speed increases, the rate of levitation increases. By surfacing, the apparent amount of drainage is reduced and the area subject to frictional resistance is also reduced. Since the first half of the hull is to float and run from the surface of the water, the only hull that is submerged under the surface of the water during actual cruising is the bottom planing surface of the latter half of the hull.

As a result of the performance study based on the data of the ship adopting the first embodiment of the present invention, the maximum ship speed was improved by 5.7% compared to the conventional ship equipped with the same type main engine. This is shown in FIG. The increase in ship speed is due to a decrease in hull resistance during operation, and the increase in speed is the same as achieving energy savings. By speeding up, the objective can be achieved with less fuel as soon as the fishing ground is reached. Conversely, the fuel consumption rate per horsepower of the main engine tends to improve on the low speed side, so if you run at the ship speed before the performance improvement, you can reduce the fuel more than the ship speed improvement.

(A) It is a side view at the time of applying the invention concerning this application to a uniaxial keel ship. (B) is a cross-sectional view in the AA line of (A). (A) is a cross-sectional view in the BB line of FIG. 1 (A). FIG. 2B is a cross-sectional view taken along the line CC in FIG. It is a cross-sectional view of the vicinity of the propeller as the second embodiment of the invention according to this application. It is a side view at the time of applying the invention concerning this application to a single axis this semi keel ship. It is a side view at the time of applying the invention concerning this application to a uniaxial bracket ship. It is a sea test result performed by the single-shaft keel ship which employ | adopted this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Skeg 2 ... Propeller 3 ... Rudder 4 ... Ship bottom planing surface 5 ... Propeller upper hull 6 ... Bottom surface of conventional ship 7 ... Convex part 8 ... Knuckle line 10 ... Water surface 11 ... Hull center line 12 ... Chinelein

Claims (3)

In a single-axle keel ship such as a fishing boat, the propeller, rudder and skeg portion in the center of the hull remain, the cross-sectional area becomes zero near the center of the hull front and rear, and gradually increases toward the rear, from near the propeller cross section and near the stern end By providing a convex part with a triangular cross section that is the right and left as the maximum, the hull sliding surface formed by an inclined surface that is close to a plane and has little torsion from the center of the hull front and back to the stern end, and the hull rear Hull structure characterized by having buoyancy. The hull structure according to claim 1, wherein a surface on a propeller side of the convex portion of the triangular section is curved. The hull structure according to claim 1 or 2, wherein the hull structure is a single-shaft semi-keel ship or a single-shaft bracket ship.

Images