CN108025799B

CN108025799B - Ship with a detachable cover

Info

Publication number: CN108025799B
Application number: CN201680054582.9A
Authority: CN
Inventors: 山本虎卓; 秋林秀聪; 藤田智; 冈沙织
Original assignee: Mitsui Engineering and Shipbuilding Co Ltd
Current assignee: Mitsui Yi ace Shipbuilding Co., Ltd.
Priority date: 2015-09-25
Filing date: 2016-09-08
Publication date: 2020-07-31
Anticipated expiration: 2036-09-08
Also published as: WO2017051713A1; CN108025799A; JP6118865B2; JP2017061270A; KR102643056B1; KR20180054646A

Abstract

The invention relates to a ship with a stern bulb, in the ship (1) with the stern bulb (20), at the stern, a stern bulb (20) is arranged in front of a propeller (10), a vertical part (22) is arranged at the lower part of the rear side of the stern bulb (20) in a downward protruding way, and the vertical part (22) and the ship body are formed into an integral structure. Thus, improvement of propulsion performance and reduction of vibration in straight traveling can be achieved by the stern bulb (20), and a relatively large counter-rotation moment against the rotation moment can be obtained even at the initial stage of rotation, resulting in excellent heading stability and a suppression effect on reduction of the propulsion performance.

Description

Ship with a detachable cover

Technical Field

The present invention relates to a ship with a stern bulb, which is provided with a stern bulb in front of a propeller at the stern, increases counter-rotating torque against the rotating torque at the initial stage of rotation, improves the stability of a route, maintains the rectifying effect at the stern bulb, and prevents the reduction of the propulsion performance.

Background

Recently, a vessel 1X with a stern bulb is adopted in which a stern bulb 20 having a shape similar to a body of revolution is provided around a propeller shaft 12 in front of a propeller 10 at the stern of the vessel as shown in fig. 10 to 12. Although this ship with a stern bulb is used for a high-speed ship requiring a speed of a certain degree or more, recently, it is considered that the ship is also applied to a low-speed ship and a medium-speed ship. Compared with the wave resistance reducing effect of a bow bulb, the stern bulb of the ship with the stern bulb is arranged in the following purposes: the wake flow flowing into the propeller is collected more, and the flow having the flow velocity as uniform as possible along the circumference of the propeller is made by smoothing the flowing flow, thereby improving the mutual interference between the hull and the propeller, that is, the propulsion performance. Further, the uniform flow also has an effect of reducing vibration.

However, in the case of this vessel with a stern bulb, particularly in a heavy vessel, since the water flow flowing from the side of the stern toward the bottom of the vessel smoothly flows, there is a problem that the counter-rotating moment by the lateral force generated at the stern portion is small at the initial stage of rotation, and the course holding performance is lowered, resulting in an unstable course.

In connection with this, as described in japanese patent application laid-open No. 8-216992, for example, the following course stabilizer for a ship hull is proposed: a skeg is arranged at the stern, a flat plate which horizontally protrudes is arranged at the lower end of the skeg, and water flow flowing into the bottom of a ship from the lateral part of the stern is blocked by the flat plate when the ship rotates, so that the ship generates a transverse force which acts in the direction of attenuating the rotating force, and the course stability of the ship is improved.

Further, for example, as described in japanese patent application laid-open No. 8-318896, the following course stabilizing fin for a ship is proposed: in a stern bulb bow ship, vertical end plates are arranged at the two side end parts of a horizontal plate fixed at the lower end of a vertical fin plate, so that vertical flow is blocked during rotation, and the course is stabilized during rotation. In the course stabilization fin of the ship, the vertical end plate also plays a role of further blocking the flow, and the vertical fin gives a large resistance to the vertical flow. The horizontal plate is formed into a trapezoidal shape when viewed from above, and is fixed to the lower end of the vertical fin with the center axis thereof.

However, although the vertical end plates at the both side ends of the horizontal plate restrict the flow above the horizontal plate, the vertical end plates are arranged at the rear portions of the vertical fins and restrict the flow above the horizontal plate on the downstream side of the rear portions of the vertical fins, and therefore the vertical end plates are considered to have little effect on the vertical fins. In addition, it is considered that wake flow collected by the stern bulb is greatly disturbed, resulting in a reduction in propulsive performance.

Patent document 1 Japanese patent application laid-open No. Hei 8-216992.

Patent document 2 Japanese patent application laid-open No. Hei 8-318896.

The results of many experiments and thinking conducted by the present inventors are the following findings: by using the vertical member having both the course maintaining performance and the propulsion performance, not only the downward flow of the water flowing into the vertical member from the lateral direction is effectively blocked at the stern on the side opposite to the rotation direction during the rotation, but also the flow rectified by the stern bulb is allowed to flow from the stern side into the propeller without being disturbed by separation or the like at the stern on the side opposite to the rotation direction, so that the lateral force acting on the hull in the direction of attenuating the rotation moment and the counter-rotation moment by the lateral force can be increased, and therefore, excellent course stability can be obtained even in a ship with a stern bulb.

In addition, the following findings were obtained: by using the vertical member having both the course holding performance and the propulsion performance, the wake collected by the stern bulb can be made to flow into the propeller without being disturbed in both the side opposite to the rotation side and the side same as the rotation side, and thus the reduction in the propulsion performance can be suppressed.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a ship with a stern bulb: the improved propulsion performance and the reduced vibration when the ship is straight can be obtained by using the stern bulb, and a larger counter-rotating moment for resisting the rotating moment can be obtained even in the initial rotation stage, so that the excellent heading stability and the effect of inhibiting the reduction of the propulsion performance can be obtained.

The ship with the stem bulb for achieving the above object is configured in a state where the stem is provided with the stem bulb in front of the propeller, and a vertical member is provided to protrude downward at a lower rear portion of the stem bulb.

According to this configuration, at the initial stage of rotation of the hull, a lateral force against the rotational moment generated by the hull is generated by the surface of the vertical member receiving the water flow flowing from the stern side to the opposite side, and the wake collected by the stern bulbous bow flows into the propeller without disturbance, so that the improvement of the course holding performance and the suppression of the reduction of the propulsive performance can be obtained.

In the above-described ship with a stern bulb, if the vertical member is formed integrally with the hull, the vertical member that generates a large lateral force can be firmly fixed to the hull.

In the above-described ship with a stern bulb, the following effects can be exhibited if the vertical member is continuously disposed so that the rear end thereof is located rearward of the rear end of the stern hub with respect to the fore-and-aft direction of the hull, and the width of the vertical member is set to 20mm or more and 25% or less of the propeller diameter.

By positioning the rear end of the vertical member rearward of the rear end of the stern boss, the magnitude of the lateral force generated by the vertical member can be increased further in the initial stage of rotation, and the point of action of the lateral force can be moved rearward of the hull, so that the counter-rotation torque against the rotation torque can be increased further.

Further, by continuously arranging the vertical members, the magnitude of the lateral force generated at the initial stage of rotation can be increased. In addition, in the case where the vertical member is divided into a plurality of pieces in the fore-and-aft direction of the hull and a gap is provided between the pieces in the fore-and-aft direction, the flow from the lateral direction enters the gap, and the flow rectified by the stern bulb is disturbed.

Further, by setting the width of the vertical member to 25% or less of the diameter of the propeller, the wake collected by the stern bulb can be made to flow into the propeller without disturbance.

In the above-described ship with a stern bulb, if the rear end portion of the vertical member is formed in a shape having projections and recesses which are matched with projections and recesses of the rotation surface of the propeller when viewed from the side of the ship body, the area of the vertical member can be increased to the maximum, and therefore the gap between the vertical member and the propeller can be minimized. Therefore, the effect of increasing the lateral force against the rotation at the start of rotation and the effect of suppressing disturbance of the water flow flowing into the propeller can be greatly increased, and the improvement of the course holding performance and the suppression of the reduction of the propulsion performance can be further achieved.

In the above-described ship with a stern bulb, if the course holding force increasing member that expands in the horizontal direction is provided at the lower portion of the vertical member, when the hull starts to rotate to the starboard side (or port side), the course holding force increasing member prevents the water flow from the lateral direction that flows into the vertical member from colliding with the vertical member and flowing out downward at the port side (or starboard side) on the opposite side, and the water flow from the lateral direction that flows into the vertical member flows rearward along the vertical member.

In the above-described ship with a stern bulb, the following effect can be exhibited if the course holding force increasing member is formed in a shape having a concave-convex portion or a tunnel portion when viewed from the rear of the hull, or in a plate-like shape having a bent shape or a corrugated shape.

In particular, by providing the uneven portion or the tunnel portion in the heading holding force increasing member, the flow of water flowing downward along the vertical member can be prevented from flowing out to the side and guided to the rear by the recessed portion (as viewed from the rear of the hull) as compared with a horizontal plate that only blocks the flow downward along the vertical member, and the flow rectified by the stern bulb can be guided to the rear along the uneven portion or the tunnel portion of the heading holding force increasing member.

At the same time, the flow of water flowing from the stern bulb is caused to flow along the vertical member by the concave-convex portion or the passage portion of the course retaining force increasing member at the starboard side (or the port side) which is the side on the same side as the rotation direction, so that the flow of water flowing from the stern bulb can be suppressed from being separated from the vertical member to generate a vortex, the instability of the approach due to the generation of the vortex can be prevented, and the disturbance of the flow of water flowing into the propeller can be suppressed, thereby suppressing the reduction of the propulsive efficiency.

Further, when the course holding force increasing member is formed in a plate shape having a bent shape or a corrugated shape, the member has a shape which is simple and easy to process, and the strength is further improved than that of a horizontal plate.

In the ship with the stern bulb, if the position of the rear end of the course holding force increasing member is set to the position of the rear end of the vertical member, the flow rectifying effect by the combination of the vertical member and the course holding force increasing member can be effectively exerted.

In the above-described ship with a stern bulb, if the course holding force increasing member is disposed in the longitudinal installation range of the hull in the 1 st region between the 1 st position located forward by 15% of the vertical line length from the stern vertical line and the 2 nd position located forward by 10% of the vertical line length from the stern vertical line, and the rear end thereof is disposed in the 2 nd region between the 3 rd position located forward by 30% of the propeller diameter from the front end of the propeller hub and the 4 th position located immediately forward by the propeller with respect to the vertical direction of the hull, the effect of the course holding force increasing member can be further improved.

According to the ship with the stern bulb of the present invention, the improvement of the propulsion performance and the reduction of the vibration in the straight running can be obtained by the stern bulb, and the large lateral force resisting the rotational moment and the anti-rotational moment by the lateral force can be obtained even at the initial stage of the rotation, and the effect of the course stability and the effect of the suppression of the reduction of the propulsion performance can be obtained.

Drawings

Fig. 1 is a side view schematically showing the structure of a stern in a ship with a stern bulb according to an embodiment of the present invention.

Fig. 2 is a rear view schematically showing the arrangement of a stern bulb, vertical members, and a heading holding force increasing member in the ship with the stern bulb of fig. 1.

Fig. 3 is a plan view schematically showing the arrangement of a stern bulb, vertical members, and a heading holding force increasing member in the ship with the stern bulb of fig. 1.

Fig. 4 is a perspective view showing the vertical member and the course holding force increasing member in a bent shape.

Fig. 5 is a rear view of the course maintaining force increasing member showing a bent shape.

Fig. 6 is a plan view of the course holding force increasing member showing a bent shape.

Fig. 7 is a side view of the course maintaining force increasing member showing a bent shape.

Fig. 8 is a rear view showing a course-maintaining-force increasing member in a corrugated shape.

Fig. 9 is a rear view showing a course maintaining force increasing member having a tunnel portion.

Fig. 10 is a side view schematically showing the structure of the stern in a ship with a stern bulb of the related art.

Fig. 11 is a rear view schematically showing the shape of a stern bulb in the vessel with a stern bulb of fig. 10.

Fig. 12 is a plan view schematically showing the shape of a stern bulb in the ship with the stern bulb of fig. 10.

Detailed Description

Hereinafter, a ship with a stern bulb according to an embodiment of the present invention will be described with reference to the drawings. As shown in fig. 1, the vessel 1 with a stern bulb has a side shell 2, a bottom 3, a rudder 4, and a propeller 10 at a stern portion, the propeller 10 is connected to a propeller hub 11, and the propeller hub 11 is fixed to a propeller shaft 12 by a propeller hub cap 13.

As shown in fig. 1 to 3, a stern bulb 20 having a shape similar to a rotating body is provided around the propeller shaft 12 at the stern, and the stern bulb 20 smoothes the flow of water flowing into the propeller 10 and produces a uniform wake distribution along the circumference Cp of the propeller 10, thereby improving the interference between the hull and the propeller 10 and improving the self-propulsion factor.

In the present invention, the vessel 1 with a stem is provided with the stem 20 at the stern, and a vertical member 22 is provided at a lower portion of the stem 20 on the rear side so as to protrude downward. The vertical member 22 is formed in an integrated structure with the hull, whereby the vertical member 22 generating a large lateral force is firmly fixed to the hull.

Accordingly, at the initial stage of rotation of the hull, a lateral force against the rotational moment generated by the hull is generated by the surface of the vertical member 22 receiving the water flow flowing from the stern side to the opposite side, and the wake collected by the stern bulbous bow 20 flows into the propeller 10 without disturbance, thereby improving the course holding performance and suppressing the reduction of the propulsive performance.

The vertical member 22 is continuously disposed such that the rear end thereof is located rearward of the stern hub rear end Xp with respect to the fore-and-aft direction of the hull. Accordingly, at the initial stage of rotation, the magnitude of the lateral force generated by the vertical member 22 can be further increased, and the point of action of the lateral force can be moved rearward of the hull, so that the counter-rotation moment against the rotation moment can be further increased.

Further, by arranging the vertical members 22 continuously, the magnitude of the lateral force generated at the initial stage of rotation can be increased as compared with the case where the vertical members 22 are divided into a plurality in the fore-and-aft direction of the hull and gaps are provided between the respective fore-and-aft directions. In other words, in a general vessel with a stem having a stem rear end located rearward of the hull, if there is a gap, the flow of water rectified by the stem 20 is disturbed due to the flow from the lateral direction entering the gap, but in this structure, the vertical member 22 is continuously formed without a gap, and therefore such disturbance of the flow of water can be avoided.

The width of the vertical member 22 is set to 20mm or more and 25% or less of the propeller diameter Dp. By setting the width of the vertical member 22 to 25% or less of the propeller diameter Dp in this way, the drag of the vertical member 22 when the hull is moving straight can be reduced. The lower limit is a plate thickness necessary for strength, and since the plate thickness varies depending on the size of the ship, 20mm is used as a value other than zero when the lower limit is set. Thereby, the wake collected by the stern bulb can be made to flow into the propeller without disturbance while maintaining appropriate strength.

Further, if the rear end portion of the vertical member 22 is formed in a shape having projections and recesses matching with the projections and recesses of the rotation surface of the propeller 10 when viewed from the side surface of the hull, the area of the vertical member 22 can be increased to the maximum, and therefore the gap between the vertical member 22 and the propeller 10 can be minimized. Therefore, the effect of increasing the lateral force against the rotation at the start of rotation and the effect of suppressing the disturbance of the water flow flowing into the propeller 10 can be greatly increased, and the improvement of the course holding performance and the suppression of the reduction of the propulsion performance can be achieved.

Further, a structure is adopted in which the course maintaining force increasing member 21 that is deployed in the horizontal direction is supported by the vertical member 22. When the hull starts to rotate to the port side (or port side), the flow of the water flowing into the vertical member 22 in the lateral direction is blocked by the course holding force increasing member 21 at the port side (or starboard side) on the opposite side from the port side to the starboard side by the vertical member 22 and flows downward, and the water flowing into the vertical member 22 in the lateral direction flows rearward along the vertical member 22, so that the lateral force against the rotational moment can be increased, and the improvement of the course holding performance and the reduction of the propulsive performance can be suppressed.

In addition, the course holding force increasing member 21 is formed in a shape having a concave-convex portion or a tunnel portion when viewed from the rear of the hull. Alternatively, the sheet-like member may be formed into a bent shape (fig. 2 and 4 to 7) or a corrugated shape (fig. 8). In addition, the channel shape is shown in fig. 9. In the bent shape and the corrugated shape, the number of the projections and the depressions may be one or more in the single board. In addition, the number of the tunnel portions may be one or more than one on the single board.

The heading holding force increasing means 21 increases the lateral force against the rotation at the start of the rotation and suppresses disturbance of the water flow flowing into the propeller 10, thereby improving the heading holding performance and suppressing the reduction of the propulsion performance. In other words, when the hull starts to turn to the starboard side (or port side), the uneven portion of the course holding force increasing member 21 prevents the water flow flowing in the lateral direction of the vertical member 22 from colliding with the vertical member 22 and flowing out in the lower and lateral directions, and the water flow flowing in the lateral direction of the vertical member 22 flows rearward along the vertical member 22, thereby preventing the lateral force from decreasing, at the port side (or starboard side) on the opposite side.

In particular, by providing the uneven portions or the channel portions in the heading direction holding force increasing member 21, the outflow of water heading downward along the vertical member 22 to the side is blocked by the recessed portions (portions of the guide passages 21a having a concave shape (fig. 5) as viewed from the rear) and guided rearward, as compared with a horizontal plate that blocks only the downward flow along the vertical member 22. In other words, the water flow directed downward along the vertical member 22 is guided rearward along the concave guide passage 21a, which is a concave portion, and the flow in the lateral direction is blocked. In addition, the flow rectified by the stern bulb 20 is guided rearward along the

guide ways

21a, 21b of the concave-convex portion of the heading holding force increasing member 21 or the guide way 21c of the tunnel portion. Thus, the flow rectified by the stern bulb 20 is guided rearward along the concave-convex portion or the tunnel portion of the course holding force increasing member 21, and the turbulence of the water flow flowing into the propeller 10 is suppressed even at the start of rotation, thereby reducing the amount of decrease in the propulsive efficiency.

At the same time, on the starboard side (or port side) which is the side on the same side as the rotation direction, the water flow flowing from the stern bulb 20 is caused to flow along the vertical member 22 by the concave guide passage 21a, the convex guide passage 21b, the tunnel-shaped guide passage 21c, and the like, which are formed by the concave and convex portions or the tunnel portion of the course holding force increasing member 21, whereby the water flow flowing from the stern bulb 20 is suppressed from being separated from the vertical member 22 to generate a vortex, and the instability of the route due to the generation of the vortex is prevented. In addition, disturbance of the water flow flowing into the propeller 10 is suppressed, and the reduction in the propulsion efficiency is reduced.

Further, it is preferable that the course holding force increasing member 21 is formed in a plate shape having a bent shape or a corrugated shape, so that the shape can be easily formed and the strength can be improved more than that of a horizontal plate.

Further, it is preferable that the rear end of the course holding force increasing member 21 is set to the rear end of the vertical member 22, and in this case, the flow rectifying effect by the combination of the course holding force increasing member 21 and the vertical member 22 can be effectively exhibited. In other words, since the downward water flow can be stopped by the course holding force increasing member 21 and the stopped water flow can be made to follow the vertical member 22, the lateral force generated by the vertical member 22 can be increased by the water flow, and the counter-rotation moment can be increased. In other words, the flow rectifying effect by the combination of the vertical member 22 and the heading holding force increasing member 21 is effectively exerted.

Further, in the attachment range of the course holding force increasing member 21 in the fore-and-aft direction of the hull, the forward end thereof is disposed in the 1 st region R1 between the 1 st position X1 located forward of the stern perpendicular line a.p. by 15% of the vertical line length L pp and the 2 nd position X2 located forward of the stern perpendicular line a.p. by 10% of the vertical line length L pp, and the rearward end thereof is disposed in the 2 nd region R2 between the 3 rd position X3 located forward of the propeller hub by 30% of the propeller diameter Dp and the 4 th position X4 located immediately forward of the propeller 10.

At the same time, the course holding force increasing member 21 is disposed in the 3 rd region R3 from the position Z1 below the half of the propeller radius (Dp/2) from the propeller center Pc to the extension of the ship bottom surface 3 (the reference line B. L.) with respect to the vertical direction of the ship body, the flow can be caused to flow into the propeller 10 while suppressing the flow disturbance from the stern bulb 20 at the start of rotation by the course holding force increasing member 21 disposed in an appropriate range with respect to the vertical direction and the vertical members 22 continuing in the forward and backward direction, and the magnitude of the lateral force generated at the start of rotation can be increased by the vertical members 22 continuing in the forward and backward direction.

Further, the immediate front of the propeller 10 refers to the front of the distance to the extent of not contacting the rotating propeller 10. Further, since the leading edge of the propeller 10 is generally convex toward the front side in the radial direction, the 4 th position changes depending on the vertical position (height) of the rear end of the course holding force increasing member 21.

Industrial applicability of the invention

According to the ship with the stern bulb of the present invention, the improvement of the propulsion performance and the reduction of the vibration in the straight traveling can be obtained by the stern bulb, and the large lateral force against the rotational moment and the counter-rotational moment by the lateral force can be obtained even at the initial stage of the rotation, and the effect on the course stability and the effect on the suppression of the reduction of the propulsion performance can be obtained, so that the ship with the stern bulb can be applied to many ships, particularly a large-sized ship with a large effect.

Description of the reference numerals

Ship with stern bulb bow

2 side planking of ship

3 boat bottom

4 rudder

10 screw propeller

11 propeller hub

12 propeller propulsion shaft

13 propeller hub cap

20 stern bulb bow

21 course holding force increasing part

21a is a concave guide path which is a concave portion when viewed from the rear of the hull

21b are convex guide paths which are convex portions when viewed from the rear of the hull

Guide path of 21c channel part

22 vertical component

Circumference of Cp Propeller

Diameter of Dp propeller

Region 1 of R1

Region 2 of R2

Position 1 forward of X1 by 15% of the vertical line length from the stern vertical line

Position 2 forward of X2 by 10% of the vertical line length from the stern vertical line

X3 position 3 forward of 30% of propeller diameter from the forward end of the propeller hub

Position 4 immediately in front of the X4 propeller

Xp aft hub rear end

Z1 is located below 50% of the propeller radius from the propeller center.

Claims

1. A ship with a stern bulb is characterized in that,

a stern bulb is arranged in front of the propeller at the stern,

a vertical component is arranged at the lower part of the rear side of the stern bulb bow in a downward protruding way,

the vertical member is continuously arranged in the fore-and-aft direction of the hull such that the rear end of the vertical member is positioned rearward of the rear end of the stern boss, and,

the width of the vertical member is 20mm or more and 25% or less of the diameter of the propeller.

2. A ship with a stern bulb is characterized in that,

a stern bulb is arranged in front of the propeller at the stern,

a course maintaining force increasing component which is unfolded in the horizontal direction is arranged at the lower part of the vertical component,

the forward and backward attachment range of the hull of the course holding force increasing member is defined by disposing the tip of the course holding force increasing member in a 1 st region between a 1 st position forward of a vertical line 15% of the vertical line length from the stern and a 2 nd position forward of a vertical line 10% of the vertical line length from the stern, disposing the rear end of the course holding force increasing member in a 2 nd region between a 3 rd position forward of a tip of the propeller hub by 30% of the propeller diameter and a 4 th position immediately forward of the propeller,

the above-described course holding force increasing means is disposed in a 3 rd region in the vertical direction of the hull, the 3 rd region being a region from a position below the center of the propeller by half of the radius of the propeller to the upper side of the extension of the bottom surface of the ship.

3. Ship with a stern bulb as claimed in claim 2,

the course holding force increasing member is formed in a shape having a concave-convex portion or a tunnel portion, or in a plate shape having a bent shape or a corrugated shape when viewed from the rear of the hull.

4. Ship with a stern bulb as claimed in claim 2 or 3,

the position of the rear end of the course holding force increasing member is set to the position of the rear end of the vertical member.

5. Ship with a stern bulb as claimed in claim 1 or 2,

the vertical member is formed as an integral structure with the hull.

6. Ship with a stern bulb as claimed in claim 1 or 2,

the rear end of the vertical member is formed into a shape having a concavity and a convexity matching with the concavity and the convexity of the rotation surface of the propeller when viewed from the side surface of the hull.