JPS61261513A - Prevention against rocking movement of elevating working platform or ship - Google Patents

Abstract

PURPOSE:To prevent rocking movement of an elevating working platform (or ship) by tidal waves during operating period by a method in which the bottom of the elevating working platform (or ship) is raised up over a range of no exposure to the water surface by a jack-up device, and the weight corresponding to the displacement is applied to legs. CONSTITUTION:For working on a working platform 1 (or ship), the platform 1 (or ship) is raised along legs 3. When the platform 1 (or ship) is raised by a height A, the weight W corresponding to the displacement is applied to the legs 3, where the floating force L1 and pushing-down force L2 of the platform 1 (or ship) by tidal waves 8 further act on the legs 3. When the floating force L1 of the platform 1 (or ship) by tidal waves 8 is smaller than the weight W corresponding to the displacement by the platform 1, no rocking movement of the platform 1 (or ship) occurs. Jack-up device having small lifting forces can thus be used, and the floating state of the platform 1(or ship) can be kept even when lowered immediately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for preventing the movement of an elevating work barge during work.

[Conventional technology]

Conventionally, as this type of work barge, an elevating type work barge disclosed in Japanese Patent Application Laid-Open No. 59-220513 by the applicant of the present invention is known. In other words, as shown in Fig. 3, this work boat has a work barge IK jacking device 2 and legs 3 (four legs in the illustrated example). By unwinding the wire 5t with a winch 4 installed on the top 1, the four legs 3t are lowered, and these legs 3 are brought to the bottom of the seabed 7. And legs 3 &
The work is carried out after the work barge 1 is raised by the jack-up device R2 along C to a sufficient height that the grained surface 6 is not affected by waves. That is, when working on the work barge 1,
K, water surface 6 to prevent the work barge l from shaking due to waves.
The work was carried out with the work barge 1 completely raised.

[Problem that the invention seeks to solve]

However, in order to raise the work barge 1 to a sufficient height where it is not affected by waves on the water surface 6, the jacking device 2 needs to have a large lifting capacity, so the cost is high. The drawback was that it took a long time to complete the process, and it took a lot of time to prepare for the work.

The present invention has been made to solve such conventional problems, and provides a method for preventing shaking of an elevating type work boat, which prevents shaking caused by waves during work without raising the work barge IYK completely above the water surface 6. This is what we are trying to provide.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention provides an elevating work barge having a jack-up device that can be raised and lowered along a plurality of legs that are placed on the bottom of the seabed. The purpose of the present invention is to prevent shaking caused by waves by raising the elevating type work barge within a range where the bottom of the elevating type work barge does not protrude above the water surface, and adding weight corresponding to the increased displacement of the elevating type work barge to the legs. That is.

[Effect]

According to the present invention, it is possible to prevent the work barge from being shaken by waves during work without completely raising the work barge from the water surface.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to an illustrated embodiment.

Note that the same parts as in the conventional example are given the same reference numerals.

The work barge l according to the present invention shown in FIG. ) and (b), upon arrival at the work area, the quinch 4 installed on the work barge unwinds 5t of wire, thereby unwinding 3t of wire from each leg.
It is lowered and these legs 3 are brought to the bottom of the ocean floor 7. next,
To carry out work on the work barge 1, as shown in Fig.
Raise along t-leg 3. At this time, the height at which the work barge 1 is raised from the water surface 6 can be set to an arbitrary height within the range where the bottom of the work barge 1 does not protrude above the water surface 6. and,
When the work barge 1 rises by a height A, a weight W corresponding to the increased displacement is applied to the four legs. Also, the first
1) is when waves 8 are applied to the work boat 1 in the state shown in FIG. 11.

The waves 8 exert a force L1 that lifts up the work barge 1 and a force that pushes it down. And, the work boat 1 t-, the weight W corresponding to the displacement lifted by the jack up device 2, is affected by the waves 8.
- If the lifting force Ll is small, the work barge 1 will not move. Conversely, if the force lifting the work barge 1' is large, leg 3
floats up, and the work barge l shakes. When the work barge is in a working area or in such a state that the force L1 that lifts the work barge 1 up by the waves 8 is smaller than the weight W, which is applied to the legs 3 and corresponds to the lifted displacement of the work barge 1, the work barge 1
It is possible to prevent the work barge l from shaking without raising it to a height where it is not affected by waves on the water surface 6.

Furthermore, when the work is completed or in case of an emergency, the work barge 1 has only risen by a height A from the water surface 6, so if the jack-up device 2 is released, the work barge 1 immediately returns to the original water surface 6.
It descends upwards and becomes a floating state (Fig. 1 (b)). Also, even if the height A at which the work barge 1 is raised changes due to the ebb and flow of the tide during work (see Figure 1 (/→)), the jack-up device 2 will not respond to the change in the height of the water surface 6. The work barge
'f: Since it can be raised or lowered, it can always be kept at a constant height AKli.

〔Effect of the invention〕

As explained above, according to the method for preventing shaking according to the present invention, it is not necessary to completely raise the work barge above the water surface, so a jack-up device with a small lifting capacity can be used, and therefore the cost is low. Moreover, since the stroke amount for jacking up can be shortened, work preparation time can be significantly shortened and work efficiency can be improved.

Furthermore, since it can be immediately lowered to a floating state at the end of work or in an emergency, it has excellent effects such as greatly improving safety.

[Brief explanation of the drawing]

Figures 1 (a) to r+ are explanatory diagrams showing the method for preventing shaking of an elevating work barge according to the present invention, (1) shows a state in which the legs are raised, and (2) shows a state in which the legs are on the bottom. , C→ is the state during work, (C) is the state in which waves are applied, FIG. 2 is a perspective view of the elevating work barge according to the present invention, and FIG.
It is a side view of the elevating type work barge in the working state of the conventional example. ...Undersea, 8...
Waves. Figure 2 Figure 3

Claims (2)

[Claims] (1) In an elevating work barge that has a jack-up device that can be raised and lowered along multiple legs that are placed on the seabed,
The jack-up device is used to raise the elevating work barge within a range where the bottom of the elevating work barge does not rise above the water surface, and the weight corresponding to the increased displacement of the elevating work barge is applied to the legs, thereby reducing sway caused by waves. A method for preventing shaking of an elevating type work barge, characterized by: (2) The method for preventing shaking of an elevating work barge according to claim 1, wherein the jack-up device is raised or lowered in response to changes in the water surface.