WO2018150912A1

WO2018150912A1 - Hull structure

Info

Publication number: WO2018150912A1
Application number: PCT/JP2018/003634
Authority: WO
Inventors: 浩太朗高野; 虎卓山本; 秀聡秋林; 沙織岡
Original assignee: 三井Ｅ＆Ｓ造船株式会社
Priority date: 2017-02-17
Filing date: 2018-02-02
Publication date: 2018-08-23
Also published as: JP2018131173A

Abstract

A hull 10 has a bow portion 20, a hull parallel portion 30 connected to the rear of the bow portion 20, and a stern portion 40 connected to the rear of the hull parallel portion 30. The cross-section of the bilge portion 33 of the hull parallel portion 30 has a linear shape. The cross-sectional shape of the bilge portions 23, 45 of the bow portion 20 and the stern portion 40 includes a curve.

Description

Hull structure

The present invention relates to an offshore floating structure including equipment for producing and storing, for example, crude oil on the ocean and a hull structure of a ship.

Conventionally, FPSO (Floating Production, Storage and Offloading system) Floating offshore oil and gas production storage and loading facility that can move to the installation sea area, is moored and fixed in the installation sea area, pumps up the oil reservoir fluid and refines and stores crude oil ) Or offshore floating structures such as FSO (Floating Storage and Offloading System). Such an offshore floating structure has a crude oil storage tank in its hull, and various facilities such as a refining treatment facility are arranged on the upper deck, so that it is formed into a box shape as a whole. In addition, it is important that such an offshore floating structure has a stable posture during operation, that is, in a moored state. Small is important.

As an offshore floating structure that satisfies both the stability during operation and the resistance performance during movement, in Patent Document 1, the central portion in the longitudinal direction of the floating body has a rectangular parallelepiped shape, and is continuously provided on the rear side of the central portion. The structure which has the streamline shape which the back part (stern part) to be narrowed toward back is proposed. On the other hand, in Patent Document 2, for the purpose of satisfying both stability and resistance performance and suppressing the manufacturing cost, the cross-sectional shape below the waterline at the center of the hull is rectangular, and is lower than the waterline at the bow. A hull shape is proposed having preferably two propulsion arches with a streamlined lower part and a stern part having a bottom inclined toward the transom and formed by a part of a cylindrical shape.

JP 2016-37214 A JP-T-2002-526323

If the cross-sectional shape below the waterline at the center of the hull is defined as a rectangle as in Patent Document 2, separation occurs when the streamline crosses the fold at the bow and stern during movement, resulting in hull resistance. On the other hand, when the bilge portion is curved like a normal merchant ship, there is a problem that the stability of rolling during operation is lowered.

An object of the present invention is to provide a hull structure that satisfies the stability of rolling during operation and the resistance performance during movement, and can suppress the manufacturing cost.

The hull structure according to the present invention is characterized in that the cross-sectional shape of the bilge portion of the parallel portion of the hull is linear, and the cross-sectional shape of the bilge portion of the bow portion and the stern portion includes a curve.

The bilge part of the hull parallel part has, for example, a flat plate shape. Moreover, a bilge keel may be provided in the bilge part of the hull parallel part. On the other hand, the cross section of the portion adjacent to the hull parallel portion of the bow portion may have a bilge portion having a linear shape. Similarly, the cross section of the part adjacent to the hull parallel part of a stern part may have a linear bilge part.

According to the present invention, it is possible to obtain a hull structure that satisfies the stability of rolling during operation and the resistance performance during movement, and can suppress the manufacturing cost.

It is the perspective view which looked at the front part of the offshore floating body structure which applied one Embodiment of this invention from diagonally downward. It is a front view of the front part of the offshore floating structure of FIG. It is a figure which shows an external shape line when a bilge part is cut | disconnected by the plane parallel to a water surface. It is the perspective view which looked at the rear part of the offshore floating body structure of FIG. 1 from diagonally downward. It is a front view of the rear part of the offshore floating body structure of FIG. It is sectional drawing which shows the bilge part of the hull parallel part of the offshore floating body structure of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. This embodiment is an offshore floating structure such as FPSO, but the present invention can also be applied to a normal ship.

1 and 2 show the front part of the offshore floating structure. This offshore floating structure can be towed to the installation sea area or can be moved by self-propulsion, and is moored and fixed in the installation sea area. The hull 10 includes a bow portion 20, a hull parallel portion 30 connected to the rear of the bow portion 20, and a stern portion 40 (FIG. 4) connected to the rear of the hull parallel portion 30. The hull parallel part 30 has a rectangular parallelepiped shape as a whole, and the side wall 31 and the bottom part 32 are flat plates. Moreover, the bilge part 33 between the side wall 31 and the bottom part 32 has the flat plate shape extended elongate along a ship length direction. That is, the hull parallel part 30 presents a rectangular parallelepiped that is chamfered at the bilge part 33.

The outer surface of the bow portion 20 is divided into an upper region 21, a lower region 22, a bilge portion 23 and a bottom portion 24. The upper region 21 is connected to the edge of the upper deck 25 and is inclined with respect to the upper deck 25 so as to form an acute angle. The lower region 22 extends vertically downward from the upper region 21. The lower region 22 is formed only by a line segment extending vertically downward, and the horizontal plane shape forms a curve whose width becomes narrower as it approaches the front end. That is, the lower region 22 is constituted by a developable surface and can be developed on a plane. 1 and 2, reference signs F1 to F4 indicate outlines of the lower region 22.

The bottom portion 24 of the bow portion 20 is a flat plate, and the bilge portion 23 is a curved surface that smoothly connects the lower region 22 and the bottom portion 24 except for a portion adjacent to the hull parallel portion 30. The shape of the curved surface of the bilge portion 23 will be described with reference to FIG. 3. The outline P obtained by cutting the bilge portion 23 along a plane parallel to the water surface is cut along a plane that includes the normal Q and is perpendicular to the horizontal surface. The cross-sectional shape of the bilge portion 23 at that time is an arc shape at a portion near the front end portion, but is a straight line at a portion adjacent to the hull parallel portion 30 (see FIG. 1). 1 and 2, reference numerals B1 to B4 indicate the cross-sectional shape of the bilge portion 23 (cross-sectional shape along the line RR in FIG. 3), and reference numerals B1 and B2 indicate the arc shape in the vertical cross section including the normal line Q. Curves when viewed in a cross section perpendicular to the ship length direction, reference numerals B3 and B4 are straight lines, and the cross-sectional shape between the reference numerals B2 and B3 is a curve of a process of smoothly changing from a curve corresponding to an arc shape to a straight line. It is.

4 and 5 show the rear part of the offshore floating structure. In the stern part 40, the upper deck 25 has the same width as the hull parallel part 30, and ideally, when the upper deck 25 of the stern part 40 is viewed from above, it has a rectangular shape. However, actually, the planar shape of the stern portion 40 is a rectangular shape including a case where a corner is chamfered or rounded. Moreover, the stern part 40 exhibits a streamline shape in which a lower part of the stern part is narrowed toward the rear than the water line during movement. The outer surface of the stern portion 40 is divided into a side wall 41, an upper region 42, an intermediate region 43, a lower region 44, a bilge portion 45 and a bottom portion 46. 4 and 5, reference signs A 0 to A 3 indicate the outlines of the side wall 41, the upper region 42, the intermediate region 43, and the lower region 44.

The side wall 41 extends vertically downward from the edge of the upper deck 25. The upper region 42 is connected to the side wall 41, and is a torsion surface having an inclined surface whose inclination angle becomes smaller as approaching the rear end portion, as indicated by outlines A0 to A3 in FIG. That is, the upper region 42 is a ruled surface (a developable surface or a twisted surface, or a combination thereof) that can be configured only by line segments. The middle region 43 is connected to the lower end of the upper region 42, and is a ruled surface having a larger inclination angle than the upper region 42 near the stern end. The lower region 44 forms a curve whose width becomes narrower as the horizontal plane shape is closer to the rear end portion, is configured by a developable surface, and can be developed on a plane.

The bottom portion 46 of the stern portion 40 is a flat plate, and the bilge portion 45 is a curved surface that smoothly connects the lower region 44 and the bottom portion 46 except for a portion adjacent to the hull parallel portion 30. The shape of the curved surface of the bilge portion 45 is a curve corresponding to the arc shape in the portion close to the rear end portion, like the bow portion 20, and changes so as to become linear as it approaches the hull parallel portion 30. . 4 and 5, reference numerals B5 to B8 indicate outlines of the bilge portion 45, reference numerals B5 and B6 are curves corresponding to the arc shape, reference numerals B7 and B8 are straight lines, and an arc shape is provided between the reference numerals B6 and B7. It is a curve of the process which changes from the curve corresponding to to a straight line.

FIG. 6 shows the bilge portion 33 of the hull parallel portion 30. A bilge keel 34 is provided in the bilge portion 33, and the bilge keel 34 extends to the vicinity of the bow portion 20 and the stern portion 40. The cross-sectional shape of the bilge part 33 is linear, and the bilge keel 34 is fixed substantially perpendicular to the surface of the bilge part 33. In FIG. 6, the broken line indicates the conventional arc-shaped bilge portion 39, and the bilge keel 34 of this embodiment has a wider width than the case where the conventional arc-shaped bilge portion is provided with the bilge keel as indicated by the symbol K. Have

Most of the bilge portion 23 of the bow portion 20 has an arc shape with a vertical cross section including the normal line Q, but the cross-sectional shape of the portion 35 adjacent to the bilge portion 33 of the hull parallel portion 30 is the same as that of the hull parallel portion 30. The adjacent portion 35 has a shape in which a flat plate is bent in the horizontal direction so as to follow the outline of the horizontal section of the lower region 22 of the bow portion 20. Further, as described above, the portion closer to the bow end than the adjacent portion 35 is formed such that the cross-sectional shape smoothly changes from a linear shape to an arc shape.

Similarly, the bilge portion 45 of the stern portion 40 has an arc shape in a vertical section including the normal line Q in the most part, but the cross-sectional shape of the portion 47 adjacent to the bilge portion 33 of the hull parallel portion 30 is the hull parallel portion. Like 30, it is linear. The adjacent portion 47 has a shape in which a flat plate is curved in the horizontal direction so as to follow the outline of the horizontal section of the lower region 44, and the portion closer to the stern end than the adjacent portion 47 has a cross-sectional shape as described above. It is shaped so as to smoothly change from a linear shape to an arc shape.

As described above, in the present embodiment, the bilge portion 33 of the hull parallel portion 30 is constituted by a single flat plate. That is, the cross section of the bilge portion 33 has a shape obtained by bending a straight line as shown in FIG. Accordingly, when the hull 10 rolls, not only the bilge keel 34 but also the fold C generates a vortex, and the roll damping force increases by the amount of the vortex, and the effect of reducing the roll increases. Further, as described above, since the width of the bilge keel 34 can be increased as compared with the prior art, the roll damping force can also be increased.

In the present embodiment, the bilge portion 23 of the bow portion 20 has an arc shape with a vertical cross section including the normal line Q in most part, so that the flow of seawater from the front of the bow portion 20 is smooth across the bilge portion 23. At the bottom 24, the hull resistance is kept small. Similarly, in the stern part 40, the flow of seawater from the bottom part 46 crosses the bilge part 45 smoothly and goes to the lower region 44, and the hull resistance is kept small.

Therefore, according to the present embodiment, the roll damping force of the hull 10 is secured, and not only the stability during operation but also the resistance performance during movement is improved. Further, since the side wall 31, the bottom 32, and the bilge portion 33 are each formed of a flat plate in the hull parallel portion 30, the manufacture of the hull parallel portion 30 is simplified and the manufacturing cost of the hull 10 can be suppressed.

In addition, although this embodiment is an example which applied this invention to the offshore floating structure, this invention is applicable also to normal ships, such as a tanker.

DESCRIPTION OF SYMBOLS 10 Hull 20 Bow part 23 Bilge part of bow part 30 Hull parallel part 33 Bilge part 34 Bilge keel 40 Stern part 45 Bilge part of stern part

Claims

The hull is a hull structure having a bow part, a hull parallel part connected to the rear of the bow part, and a stern part connected to the rear of the hull parallel part,
A hull structure characterized in that a cross-sectional shape of a bilge portion of the hull parallel portion is linear, and a cross-sectional shape of a bilge portion of the bow portion and the stern portion includes a curve.
The hull structure according to claim 1, wherein the bilge portion of the parallel portion of the hull has a flat plate shape.
The hull structure according to claim 1 or 2, wherein a bilge keel is provided in a bilge portion of the hull parallel portion.
The hull structure according to any one of claims 1 to 3, wherein a cross section of a portion adjacent to the hull parallel portion of the bow portion has a linear bilge portion.
The hull structure according to any one of claims 1 to 4, wherein a cross section of a portion of the stern portion adjacent to the hull parallel portion has a straight bilge portion.