JPS62105795A - Propulsion method for ship equipped with yawing type propeller - Google Patents

Abstract

PURPOSE:To enable the prevention of interference among a plurality of yawing type propellers on the bottom of an offshore structure and the like by making the upperstream side of propellers rotatable toward an outboard direction about the center line of the bottom. CONSTITUTION:Yawing type propellers 4a and 4b at the upperstream side are directed outboard with an angle of 50 deg. (beta) or less, resisting advance resistance 'R' or an external force 'F'. Consequently, an aft-flow from respective propellers 4a and 4b has no effect upon yawing type propellers 4d and 4c at the downstream side, and the thrust of said propellers 4d and 4c increases. Also, a lower hull 1a subjected to an influence by the aft-flow can be shortened, thereby reducing frictional resistance and enabling the effective use of thrust generated by the yawing type propellers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for propulsion of a marine structure equipped with an oscillating propeller or a ship equipped with an oscillating propeller, such as a ship.

[Conventional technology]

Figures 2 to 7 show examples of conventional propulsion methods for ships equipped with oscillating propellers. Figure 2 is a side view of a ship equipped with one propeller, Figure 3 is a front view, and Figure 4 is a The plan view, Figure 5, is for a single-equipped ship sailing.

Figure 6 is a graph showing the relationship between the 4m force and the length of the σ whirlpool affected by the wake, and Figure 7 is a graph showing the relationship between the upstream propeller and the 4m force when the ship's bottom centerline is maintained. A graph showing the relationship between the distance between the propellers and the thrust in the situation where the propellers are installed in the downstream propellers is shown in Figures 2 to 4. The deck section 3 is mounted on columns 24-211. Places 5a-5cu Column 2a.

2e and the deck section 3, respectively. Oscillating propellers 4a to 4d are installed on the bottom of the lower hull 1d. Oscillating propeller 40-411 halo'7-ha, /1z
The operational status of the oscillating propeller installed on the bottom of the ship 1b when the 7 offshore structure navigates to a work site or when maintaining a fixed position against disturbance F from the front during oil drilling work. As shown in Figure 5, 3 From Figure 5, lower hull 1a
I wrote about the oscillating propellers 4a to 4d installed on the bottom of the ship, but they were installed on the bottom of the other ship. The i-oscillating propellers 40 to 4 [) are in a similar operating situation.

The oscillating propeller does not have an angle to the longitudinal centerline of the ship's bottom; in other words, it operates parallel to the longitudinal centerline of the ship's hull, generating thrust T, which overcomes the ship's resistance and propels the ship forward. A fixed position is maintained by generating a thrust force T equivalent to the disturbance F from the front.

[Problem that the invention seeks to solve]

In Fig. 5, when the oscillating propellers 4a to 4b operate, the flow from the oscillating propellers flows rearward along the bottom of the lower hull, and as the wake flows along the bottom of the ship, frictional resistance is generated on the lower hull. The effectiveness of the thrust T generated by the oscillating propeller is reduced by the amount of frictional resistance.

Figure 6 shows the results of investigating the amount of increase in frictional resistance due to the wake of a four-stroke propeller. The longer the length of the lower wheel, which is affected by the wake of the oscillating propeller, the greater the frictional resistance.

The effective thrust in the figure is represented by (generated thrust) - (frictional resistance).

Regarding the lower hull la in FIG. 5, since the oscillating propellers 4a, 4d, and 41) and 40 are arranged in a straight line approximately parallel to the bottom centerline, the oscillating propellers 4d and 4a, 4+] is affected by the wake of 4b, so the generated thrust is reduced. The survey results are shown in Figure 7. It can be seen that the thrust generated by the oscillating propeller, which directly receives the wake of the oscillating propeller, becomes smaller as the two become closer together. As described above, there is a problem in that the effectiveness of the thrust generated by the oscillating propeller installed on the bottom of the conventional lower hull is greatly reduced due to the influence of the wake generated by the oscillating propeller.

The present invention solves the above problems (8), but the wake generated by the oscillating propeller on the upstream side directly affects the oscillating propeller disposed on the wake side. A further object of the present invention is to provide a propulsion method for a ship equipped with an oscillating propeller that can shorten the length of the lower hull behind the propeller.

[Means for solving problems]

Therefore, the method for propulsion of a ship equipped with an oscillating propeller according to the present invention is a method for propulsion of a ship equipped with a plurality of oscillating propellers installed on the bottom of a marine structure or ship for navigation and fixed position maintenance. , the oscillating propeller on the upstream side of the bottom of the ship is provided so as to be rotatable outward with respect to the centerline of the bottom of the ship for propulsion.

[Effect]

``With the above configuration, 1. The swing type propeller on the upstream side is operated to open outward at an angle of IjN~, and the wake generated by the swing type propeller on the upstream side is placed on the wake side. Since there is no direct influence on the propeller, the thrust generated by the oscillating propeller on the wake side increases, and the length of the lower hull, which is affected by the wake, becomes shorter, reducing frictional resistance. As a result, the thrust generated by the oscillating propeller is effectively utilized.

〔Example〕

FIG. 1 is an embodiment of the propulsion method for an oscillating propeller-equipped fa ship according to the present invention, and is an explanatory diagram of the operating state when the ship equipped with nine propellers is sailing or maintaining a fixed position.

According to Figure 1, 4-stroke propellers 4, 1 and 4 on the second stream side
b opens outward at an angle within 50° (β) and opposes forward resistance I (or external force F. Therefore, 4a (
Since the wake of 4b) does not affect 4d (4c), 4
d (4c) The thrust generated by the oscillating propeller increases and the length of the lower hull, which is affected by the wake, is shortened, so the frictional resistance is reduced and the thrust generated by the oscillating propeller is effectively utilized. .

Note that the description of the marine structure is the same as in the conventional example.

[4) Effect of the Invention] As detailed above, an oscillating propeller is generated by preventing the reduction in thrust due to interference between propellers and reducing the frictional resistance caused by the wake generated by a single oscillating propeller. This has the effect of increasing the effectiveness of thrust.

[Brief explanation of drawings]

FIG. 1 is an embodiment of the method for propulsion of a ship equipped with an oscillating propeller according to the present invention, and is an explanatory diagram of the operating situation when a ship equipped with two propellers is sailing or maintaining a fixed position. Figures 2 to 7 show examples of conventional propulsion methods for ships equipped with oscillating propellers.1 Figure 2 is a side view of a ship equipped with nine propellers, Figure 3 is a front view, and Figure 4 is a The plan view, Figure 5, is for a single-equipped ship sailing. Figure 6 is a graph showing the relationship between the length of the lower hull affected by the wake and the thrust force. , is a graph showing the relationship between the distance between the propellers and the thrust in a situation where an upstream propeller and a downstream propeller are disposed. la, lb...Lower...le, 4a
, 4b... Upstream oscillating propeller, 4c
, 4d...Downstream oscillating propeller. Art number S diagram

Claims (1)

[Claims] In a propulsion method for a ship equipped with multiple oscillating propellers installed on the bottom of a marine structure or ship for navigation and maintaining a fixed position, the oscillating propeller on the upstream side of the bottom of the ship is aligned with respect to the center line of the bottom of the ship. A method for propulsion of a ship equipped with an oscillating propeller, characterized in that the propeller is rotatable in an outward direction.