JP2011116231A - Method for double hull structure of single hull cargo ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that the conversion of a single hull cargo ship (a single hull tanker) into one having a double hull is preferable in prolonging the life of a precious property; however, the construction period is very long in an existing method; the stop of the operation during that time raises another problem; and the construction cost is enormous. <P>SOLUTION: A main part 5 of a double hull structure which houses a cargo tank or a cargo hold part of an objective ship 1 and on each side of which an detachable buoyant tank 6 is provided is constructed in advance, and is launched and held at a wharf. The draft of the arrived objective ship and the draft of the main part of the double hull structure are adjusted. Then, the main part of the double hull structure is moved from a fore side or an aft side of the objective ship, and the ship and the double hull structure are suitable for each other. Thereafter, an installation work, an integration work and a painting work of other double hull structure other than the main part are executed. The double hull structure is rotatable around a rotational shaft 53 at the center of a bottom portion in the longitudinal direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an efficient method for converting a single hull cargo ship, particularly a single hull tanker, into a double hull (double hull).

  An international maritime organization examined the large-scale oil spill caused by an oil tanker off the coast of Spain in November 2002. In December 2003, the Marine Environment Conservation Committee (MEPC50) An amendment to the “Marine Pollution Control Convention” aimed at promoting the phase-out and the early introduction of double hull tankers has been adopted, and since May 19, 2005, Annex VI has become effective. In line with this, revisions to relevant ministerial ordinances have been promulgated and implemented in Japan.

  In short, the amendment is to ban the transportation of heavy oil in single hull tankers, although transitional measures will be taken. Roughly speaking, for tankers with over 600 tonnes (DWT), single hull tankers with over 5000 DWT have been phased out by 2010 (with some exceptions), and heavy oil transportation Is that the entry country can refuse entry of the ship from 2005 for tankers of 5000 DWT or more and from 2008 for tankers of 600-5000 DWT.

  The shipowner must respond accordingly to this revision. However, a tanker is a property that has been built with tremendous amount of money and time, and if there are no problems with other hull structures, propulsion engines, cargo handling facilities, etc., the strategy of responding by remodeling is naturally the first option. is there.

For this reason, the present inventor has proposed a construction method in which a double hull structure portion is built in advance in a state where a final hull as a single hull freighter can be combined, and this is integrated offshore. Patent Document 1 is that and the feature is that the main ship of the double hull structure that wraps the cargo tank or cargo hold of the target ship is built in advance, put on hold at the quay, and entered the port And adjusting the draft of the main part of the double hull structure, moving the main part of the double hull structure from the front or rear of the target ship and fitting them together, and then double hull structure other than the main part This is a method of performing body installation work, integration work, and painting work, and is that detachable buoyancy tanks are respectively installed on both sides of the main part of the double hull structure.
As a premise of the present invention, there is a fact that the “cargo oil tank” portion of the active tanker is almost parallel to the ship width except for the end portion. This makes it possible to “insert the double hull structure while sliding”.

JP 2009-1113734 A

However, on the ocean, it is actually difficult to fit the double hull structure part while sliding the single hull cargo ship. The reason is that although the size and weight of the double hull structure are large, the gap between the inside of the double hull structure and the outside of the single hull cargo ship is small, and in addition, the slide length is very long. As a result, the slide operation has to be very careful and time consuming, and still tends to be damaged by contact.

  Therefore, the present inventor has finally made the present invention as a result of intensive studies in view of these points, and the feature of the present invention is that it wraps the cargo tank or cargo hold part of the target ship, and each of the both sides thereof. The main part of the double hull structure where a detachable buoyancy tank is installed is built in advance and then launched and retained on the quay, and the draft of the target ship and the main part of the double hull structure are adjusted. And then moving the main parts of the double hull structure from the front, rear or lower side of the target ship and fitting them, and then installing the double hull structure other than the main part, integration work, painting In this construction method, the double hull structure is rotatable about the bottom center longitudinal direction as a rotation axis.

  In short, the present invention is constructed in such a way that the double hull structure part can be combined in advance at the last port of entry as a single hull cargo ship and fitted into the single hull cargo ship while sliding or floating the double hull structure part. The width of the double hull structure is widened and returned to the original position when the integrated work position is reached.

  Here, the “double hull structure” is a structure that wraps the cargo tank or cargo hold portion of the target single hull cargo ship, for example, the cargo oil tank portion in the case of an oil tanker. Double hulling that meets legal requirements will be achieved. This structure has a structure along each target tanker and is basically constructed individually. Also, during construction, the main hull structure is moved from the front, rear, or lower side of the target tanker to fit them together, making the fitting impossible or difficult. The structural part is omitted and built, and is installed after fitting. That is, both the part to be constructed before fitting and the part to be installed after fitting are collectively referred to as a “double hull structure”. In other words, the “double hull structure” includes a part that is built in advance and a part that is installed in the ship body after fitting, and the part that is built in advance is referred to as a “main part”. Of course, it is more efficient that the main body is designed to be as large as possible.

  Further, the double hull structure has a structure that is rotatable about the central longitudinal direction of the bottom. The details of the rotating structure are not particularly limited. A structure such as a hinge is typical, but the rotation axis needs to be linear in order to be able to rotate. Further, the pivotable area does not need to be large, and it is sufficient if it is widened by 5 to 10 °. In addition, when the slide for assembling into the single hull cargo ship or the levitation work is completed, the spread double hull structure is closed. After that, there is no need to open it. Accordingly, rotation may be disabled at this stage by welding or other means.

By the way, the operation | work which fits a double hull structure to a target ship is performed by the method of a slide or levitation | floating.
“Slide” means that the double hull structure is located in front of or behind the target ship and is moved or coasted to a predetermined position. The buoyancy tank is adjusted for buoyancy to adjust the waterline, but the double hull structure need not be submerged.
“Floating” refers to a method in which a double hull structure is floated in a state where the double hull structure is submerged in advance and the target ship remains at the sea level. There are two methods for sinking: a method of connecting and fixing the seabed and the double hull structure while keeping the air in the buoyancy tank as it is, and a method of discharging the air in the buoyancy tank.

  In addition, the double hull structure is slightly opened up to the target ship position, but the structure and method for opening the structure are not particularly limited. For example, the split left and right double hull structures are connected by temporary welding in an open state, and this connection is released when the position reaches the designed position, or the double hull divided by another drive source. There is a method of pulling the left and right sides of the structure outward.

If necessary, the dock may be temporarily inserted into the dock in order to perform various operations on the fitting portion on the ship body side (a range where the double hull is used). In that case, the uniting with the main part of the double hull structure is after the dock is brought out. The various operations include removal / cleaning of deposits, re-coating of the outer surface of the outer plate, various modifications accompanying changes in specifications, removal of gas inside the cargo tank, and the like.

  The double hull conversion method for a single hull cargo ship according to the present invention is an extremely advanced invention having the following effects.

(1) By making effective use of existing ships, it is possible to extend the life of valuable assets.
(2) Since the main part of the double hull structure is constructed separately from the ship body, the operation suspension period due to docking of the ship body can be greatly shortened.
(3) Since the main part of the double hull structure has a buoyancy tank, it can exist on the ocean by itself without the need for crane lifting.
(4) The loading weight ton of the target ship increases due to the addition of the double hull structure.
(5) The double hull structure itself is rotated to widen the width when the single hull cargo ship is fitted.

(A) (b) shows an example of the single hull tanker which is the object of the construction method of the present invention, where (a) is a schematic plan view and (b) is a schematic side view. (A) (b) shows the construction example of the main part of the double hull structure for the target tanker shown in FIG. 1, (a) is a schematic front view, and (b) is a schematic side view. It is. It is a schematic front view which shows the draft position on the sea of the main part of an object tanker and a double hull structure. It is a schematic side view which shows the state which temporarily attached the main part of the double hull structure to the object tanker, and inserted into the dock. It is a schematic front view which shows another example of this invention construction method.

Hereinafter, the method of the present invention will be described in more detail with reference to the drawings.

  1 (a) and 1 (b) show an example of a single hull tanker 1 which is an object of a double hull conversion method for a single hull cargo ship according to the present invention. FIG. 1 (a) is a schematic plan view. b) is a schematic side view. As is clear from the figure, the target tanker 1 of this example is a so-called oil tanker, which is a cargo oil tank section 2 (corresponding to a cargo tank in the general cargo ship) that occupies most of the volume, and a bow at the front and back It is the ship which became the structure where the part 3 and the engine room part 4 were arrange | positioned. The cargo oil tank section 2 is divided into a plurality of parts, but the description thereof is omitted. The zone where the double hull structure is required is mainly the cargo oil tank portion 2.

  Further, the cargo oil tank portion 2 has a parallel hull for the portion L in the entire length, and the length of the portion other than L is only slight. Further, the bottom of the ship is linear in terms of this L portion.

  FIGS. 2A and 2B show an example of construction of the main portion 5 of the double hull structure for the target tanker 1 shown in FIG. The main body 5 assembles and separates the separated divided bodies 51 in the dock. Further, buoyancy tanks 6 are installed on both sides of the main body 5. The buoyancy tank 6 of this example has a length that is approximately half of the total length of the main body 5 of the double hull structure, and is provided with a partition inside to allow for front-rear balance adjustment. The buoyancy tank may be arranged. The buoyancy tank 6 is removed when the double hulling work is completed. At this time, in order to simplify the removal work, temporary frame members 52 are provided on both sides of the main body 5 of the double hull structure. Is attached, and the main body 5 of the double hull structure is floated by lifting it with buoyancy. Accordingly, when the double hulling work is completed, the buoyancy of the buoyancy tank 6 is reduced and the buoyancy can be easily separated by sinking. Since the temporary frame member 52 is also removed thereafter, it is preferable that the temporary frame member 52 is attached in advance so that it can be easily removed.

  The main body 5 has a rotation shaft 53 along the longitudinal direction of the center of the bottom, and the left and right are rotatable relative to each other. However, in the case of this example, in the main body part 5 construction stage, it is temporarily welded by the connecting rod 54 so that the rotation is fixed with the upper end slightly opened from the normal position.

  The main part 5 of the completed double hull structure puts seawater into and out of the dock. At this time, since it only floats due to the presence of the buoyancy tank 6, it is moved to an appropriate position on the quay by borrowing external force such as a tugboat.

At this stage, the united work with the target tanker 1 which is the main body of the ship is started for the first time. Therefore, it is possible to operate the ship until this stage.
FIG. 3 shows an example of a state in which the target tanker 1 and the main portion 5 of the double hull structure are to be combined. The width of the main portion 5 of the double hull structure is larger than the width of the target tanker 1 by temporary welding. Further, by reducing the buoyancy of the buoyancy tank 6, the risk that the bottom of the target tanker 1 contacts the main body 5 during movement is reduced.
In this way, when the mutual position is as designed, the buoyancy of the buoyancy tank 6 is increased, and the connecting rod 54 is removed before and after that to complete the temporary combination.

  After coalescence, as shown in FIG. 4, the target tanker 1 (with the main part 5 of the temporarily mounted double hull structure) is inserted into the dock, the remaining double hull structure is attached, and further, main welding and construction work are performed. The construction is finished.

  FIG. 5 shows another example of the construction method according to the present invention. After the main body 5 of the double hull structure is built in the dock, seawater is introduced, and the target tanker 1 is inserted into the dock and united. is there. In the case of this example, the main body portion 5 is on the seabed at the uniting operation stage, and a method of connecting and fixing the seabed with the chain 55 is adopted. When the target tanker 1 reaches a predetermined position, the chain 55 is removed, and the main body portion 5 is floated to be integrated. The levitation is performed by the buoyancy of the buoyancy tank 6, and it is dependent on the tensile force of the chain 55 to increase the width of the main body portion 5 than the width of the target tanker 1. Therefore, unlike the construction method of the previous example, the drive source for moving the main body and the posture maintaining member such as the connecting rod 54 can be omitted.

In addition, although the single hull oil tanker has been described as an example of the target ship so far, the present invention construction method is not limited to the oil tanker, but is applied to other tankers or cargo ships such as general cargo ships, container ships, and car carriers. In addition, even if the construction method of the present invention is applied as part of remodeling work when changing the use of another cargo ship to a tanker, the effect is tremendous (not shown).

1 Single hull tanker (target tanker) subject to the construction method of the present invention
2 Cargo oil tank part 3 Bow part 4 Engine room part 5 Main part of double hull structure 51 Divided body 52 Temporary frame material 53 Rotating shaft 54 Connection rod 55 Chain 6 Buoyancy tank

Claims (2)

  The main part of the double hull structure that wraps the cargo tank or cargo hold of the target ship and has detachable buoyancy tanks on both sides of it is launched in advance and suspended on the quay. In addition, after performing draft adjustment of the main part of the target ship and the double hull structure that entered the port, the main part of the double hull structure is moved from the front or the rear of the target ship to fit them, A construction method for performing installation work, integration work, and painting work for a double hull structure other than the main body, wherein the double hull structure is rotatable about the bottom center longitudinal direction as a rotation axis. Double hull conversion method for single hull cargo ship.   2. The double hull construction method for a single hull cargo ship according to claim 1, wherein the pivot shaft also serves as a keel plate.

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