liquefied gas carrier

Abstract

To provide a liquified gas carrier that a position of a rear mast light is lower than the rear mast light installed in a stern zone.SOLUTION: A liquified gas carrier comprises: a hull 10 including a cargo area 13 between a bow compartment 11 and a stern compartment 12; multiple cargo tanks 21, 22, 23 and 24 linearly arranged in the longitudinal direction in the cargo area; multiple tank covers 31, 32, 33 and 34 to cover the multiple cargo tanks from their tops; multiple vent masts 41, 42, 43 and 44 extending upward from the multiple tank covers; a front mast light 50 located in the bow compartment; and a rear mast light 60 installed in the center in the lateral direction of any one of the multiple tank covers.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to liquefied gas carriers. [Background technology]

[0002] Large ships are equipped with forward and aft mast lights in accordance with the International Collision Regulations at Sea (CORLEG). The regulations stipulate the installation height of each mast light. In particular, the regulations stipulate that the aft mast light must be visible separately from the forward mast light from a specified distance (1,000 m) above the sea surface ahead, and the forward and aft mast lights must be positioned at least half the ship's overall length or 100 m apart, whichever is shorter. Generally, the forward mast light is installed in the bow compartment, and the aft mast light is installed in the stern compartment (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-55692 Summary of the Invention [Problem to be solved by the invention]

[0004] On liquefied gas carriers, cargo tanks and associated structures such as tank covers are installed forward of the stern compartment, and in order to comply with the above regulations, the rear mast light must be positioned higher than these structures. However, if the rear mast light is positioned too high, the support pole for the rear mast light must be longer, which can cause problems with the strength of the support pole and the maintenance of the rear mast light. In addition, if the rear mast light is positioned too high, it may be subject to restrictions on navigation routes, such as being unable to pass under bridges.

[0005] Therefore, an object of the present disclosure is to provide a liquefied gas carrier in which the position of the rear mast light is lower than when the rear mast light is installed in the stern compartment. [Means for solving the problem]

[0006] A liquefied gas carrier according to one embodiment of the present disclosure comprises a hull including a cargo area between a bow compartment and a stern compartment, a plurality of cargo tanks arranged in a longitudinal direction within the cargo area, one or more tank covers covering the plurality of cargo tanks from above, one or more vent masts extending upward from the one or more tank covers, a forward mast light located in the bow compartment, and a rear mast light installed in the left-right center of one of the one or more tank covers. [Effects of the Invention]

[0007] According to the above configuration, it is possible to provide a liquefied gas carrier in which the rear mast light is positioned lower than when it is installed in the stern compartment. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic side view of a liquefied gas carrier. [Figure 2] FIG. 2 is a schematic plan view of a liquefied gas carrier. DETAILED DESCRIPTION OF THE INVENTION

[0009] A liquefied gas carrier 100 according to an embodiment will be described below. The liquefied gas carrier 100 according to this embodiment is a ship that transports liquefied gases such as liquefied hydrogen (LH2), liquefied natural gas (LNG), and liquefied petroleum gas (LPG). Fig. 1 is a schematic side view of the liquefied gas carrier 100, and Fig. 2 is a schematic plan view of the liquefied gas carrier 100. The concept of direction in the following description coincides with the concept of direction when a passenger on the liquefied gas carrier 100 looks in the direction of navigation (to the right on the paper in Figs. 1 and 2).

[0010] As shown in Figure 1, a liquefied gas carrier 100 according to this embodiment includes a hull 10, a plurality of cargo tanks 21-24, a plurality of tank covers 31-34, a plurality of vent masts 41-44, a forward mast light 50, and an aft mast light 60. These components will be described below in order.

[0011] <Hull> The hull 10 includes a bow compartment 11, which is the forward portion, a stern compartment 12, which is the aft portion, and a cargo area 13 located between the bow compartment 11 and the stern compartment 12. In other words, the portion of the hull 10 forward of the cargo area 13 is the bow compartment 11, and the portion aft of the cargo area 13 is the stern compartment 12. In this embodiment, an accommodation area 15 where passengers live is located above an upper deck 14 of the bow compartment 11, and a bridge 16 where passengers work is located above the accommodation area 15. However, the locations of the accommodation area 15 and the bridge 16 are not limited to those described above. In addition, an engine room 17 is located in the stern compartment 12, and the engine room 17 houses a main engine that drives a screw propeller 18.

[0012] <Cargo Tank> The liquefied gas carrier 100 according to this embodiment is equipped with, in order from the front, a first cargo tank 21, a second cargo tank 22, a third cargo tank 23, and a fourth cargo tank 24. These cargo tanks 21 to 24 store the liquefied gas to be transported. These cargo tanks 21 to 24 are located in the cargo area 13 of the hull 10 and are lined up in the fore-and-aft direction. Each of the cargo tanks 21 to 24 is spherical or ellipsoidal, and the upper portion of each of the cargo tanks 21 to 24 is located above the upper deck 14. However, the number and shape of the cargo tanks 21 to 24 are not limited to those described above.

[0013] <Tank cover> The tank covers 31 to 34 are members that cover the cargo tanks 21 to 24 from above. The liquefied gas carrier 100 according to this embodiment is equipped with, in order from the front, a first tank cover 31 that covers the first cargo tank 21, a second tank cover 32 that covers the second cargo tank 22, a third tank cover 33 that covers the third cargo tank 23, and a fourth tank cover 34 that covers the fourth cargo tank 24. These tank covers 31 to 34 are hemispherical and located above the upper deck 14. However, the number and shape of the tank covers are not limited to those described above. For example, the liquefied gas carrier 100 may be equipped with one or more tank covers, each of which may be installed to cover multiple cargo tanks.

[0014] <Bent Mast> The vent masts 41-44 are facilities that release gases, such as boil-off gas, generated when liquefied gas stored in the cargo tanks 21-24 evaporates to the outside. The liquefied gas carrier 100 according to this embodiment is equipped with, in order from the front, a first vent mast 41 extending upward from the first tank cover 31, a second vent mast 42 extending upward from the second tank cover 32, a third vent mast 43 extending upward from the third tank cover 33, and a fourth vent mast 44 extending upward from the fourth tank cover 34. However, the number of vent masts is not limited to the above. For example, multiple vent masts may extend from one tank cover, or vent masts may extend from only some of the tank covers.

[0015] Here, the dashed dotted line in Fig. 2 is a center line that passes through the left-right center of the hull 10 and the left-right centers of each of the tank covers 31 to 34. As shown in Fig. 2, the first vent mast 41 is located to the left of the left-right center of the first tank cover 31. However, the first vent mast 41 may also be located at the left-right center of the first tank cover 31. The reason why the first vent mast 41 is located to the left of the left-right center of the first tank cover 31 will be described later.

[0016] On the other hand, the second vent mast 42 is located at the left-right center of the second tank cover 32, the third vent mast 43 is located at the left-right center of the third tank cover 33, and the fourth vent mast 44 is located at the left-right center of the fourth tank cover 34. However, each of the vent masts 42 to 44 may be located to the left or right of the left-right center of the corresponding tank cover 32 to 34. Also, each of the vent masts 41 to 44 is located rearward of the front-rear center of the tank cover 31 to 34.

[0017] <Fore mast light> The forward mast light 50 is a mast light located further forward than the aft mast light 60. The forward mast light 50 may not be explosion-proof. In this embodiment, the forward mast light 50 is located in the bow section 11 and attached to the upper part of the bridge 16. The forward mast light 50 is located in the center of the hull 10 in the transverse direction. The forward mast light 50 can be seen from a reference point on the sea surface a predetermined distance (e.g., 1,000 m) forward of the hull 10. The straight dashed line passing over the tank covers 31-34 in Figure 1 is a straight line (hereinafter referred to as the "reference line") 51 that extends from the above-mentioned reference point and passes through the forward mast light 50.

[0018] <Rear mast light> The rear mast light 60 is a mast light located rearward of the forward mast light 50. The rear mast light 60 may be explosion-proof. In this embodiment, the rear mast light 60 is located in the cargo area 13 rather than in the stern section 12, and is attached to the second tank cover 32 via a support 61. The rear mast light 60 is also located forward of the second vent mast 42 extending from the second tank cover 32. Furthermore, as shown in FIG. 1, the rear mast light 60 is located above the reference line 51. This allows the rear mast light 60 to be seen above the forward mast light 50 from the reference point.

[0019] In this embodiment, the first vent mast 41 is located in front of the rear mast light 60, but as described above, the first vent mast 41 is located to the left of the center in the left-right direction of the first tank cover 31. Therefore, when viewed from a reference point, the rear mast light 60 can be seen without being higher than the first vent mast 41. Therefore, according to this embodiment, not only the front mast light 50 but also the rear mast light 60 can be seen from the reference point. In this embodiment, the first vent mast 41 is located to the left of the center in the left-right direction of the first tank cover 31, but it may be located to the right. For example, if a flying passage is installed that passes over the tank covers 31 to 34, the position of the first vent mast 41 should be determined so that it does not interfere with the flying passage.

[0020] Here, if the rear mast light 60 were to be installed in the stern section 12, in order to make the rear mast light 60 visible from the reference point higher than the forward mast light 50, that is, to position the rear mast light 60 above the reference line 51, the rear mast light 60 would have to be positioned very high. In particular, if no structures such as the accommodation space 15 are installed in the stern section 12, the support pole 61 supporting the rear mast light would need to be very long, which is disadvantageous from the standpoints of design and cost. In contrast, in the present invention, the rear mast light 60 is installed in the second tank cover 32 of the cargo area 13, so the rear mast light 60 can be positioned lower than when it is installed in the stern section 12, which is advantageous from the standpoints of design and cost. However, in this embodiment, the rear mast light 60 is positioned 4.5 m or more above the forward mast light 50 in accordance with the International Maritime Regulations.

[0021] In this embodiment, the rear mast light 60 is installed on the second tank cover 32, but as long as it complies with the International Collision Regulations, it may be installed on a tank cover other than the second tank cover 32. Even in this case, the position of the rear mast light 60 can be lowered compared to when it is installed in the stern section 12.

[0022] Furthermore, it is desirable to install the rear mast light 60 on a tank cover corresponding to a cargo tank other than the rearmost cargo tank among the multiple tank covers 31 to 34, and it is desirable to install it on a tank cover as forward as possible while satisfying the International Collision Regulations. By installing the rear mast light 60 on a forward tank cover, the position of the rear mast light 60 can be lowered.

[0023] In addition, in this embodiment, the rear mast light 60 is attached to the second tank cover 32 via the support 61, but it may also be attached to the second tank cover 32 via the second vent mast 42. In this case, the support 61 can be omitted.

[0024] <Summary> As described above, the liquefied gas carrier of this embodiment comprises a hull including a cargo area between a bow compartment and a stern compartment, a plurality of cargo tanks lined up in the fore-and-aft direction within the cargo area, one or more tank covers covering the plurality of cargo tanks from above, one or more vent masts extending upward from the one or more tank covers, a forward mast light located in the bow compartment, and a rear mast light installed in the left-right center of one of the one or more tank covers.

[0025] With this configuration, the rear mast light can be positioned lower than when it is installed in the stern compartment.

[0026] In addition, in the liquefied gas carrier according to this embodiment, the aft mast light is installed on a tank cover corresponding to a cargo tank other than the rearmost cargo tank among the one or more tank covers.

[0027] This configuration allows the rear mast light to be positioned lower.

[0028] In addition, in the liquefied gas carrier according to this embodiment, the vent mast extending from the tank cover located forward of the rear mast light is located to the right or left of the center of the tank cover in the left-right direction.

[0029] With this configuration, even if the position of the rear mast light is lower than the height of the forward bent mast, the rear mast can still be seen from the reference position, so the rear mast light can be positioned even lower.

[0030] In addition, in the liquefied gas carrier according to this embodiment, the aft mast light is located forward of the vent mast extending from the tank cover on which the aft mast light is installed.

[0031] With this configuration, even if the vent mast extending from the tank cover on which the rear mast light is installed is positioned in the center in the left-right direction, the rear mast light can be seen from the reference position.

[0032] In addition, in the liquefied gas carrier according to this embodiment, the rear mast light is explosion-proof.

[0033] With this configuration, even if flammable gas flows near the rear mast light, the rear mast light will not become an ignition source for the flammable gas.

[0034] In addition, in the liquefied gas carrier according to this embodiment, the rear mast light is installed on the tank cover via the vent mast.

[0035] With this configuration, the rear mast light can be installed on the tank cover without using a dedicated support pole to support the rear mast light. [Explanation of symbols]

[0036] 10 Hull 11. Bow compartment 12 Aft compartment 13 Cargo Area 21 No. 1 Cargo Tank 22 No. 2 Cargo Tank 23 No. 3 Cargo Tank 24 No. 4 Cargo Tank 31 First tank cover 32 Second tank cover 33 Third tank cover 34 4th Tank Cover 41 No. 1 Bent Mast 42 No. 2 Bent Mast 43 Third Bent Mast 44 No. 4 Bent Mast 50 Forward Mast Light 60 Rear Mast Light 100 Liquefied Gas Carriers

Claims

1. a hull including a cargo area between a bow compartment and an aft compartment; a plurality of cargo tanks arranged along the longitudinal direction within the cargo area; One or more tank covers covering the plurality of cargo tanks from above; one or more vent masts extending upwardly from the one or more tank covers; a forward mast light located in the bow section; a rear mast light installed in the center of the left-right direction of any of the one or more tank covers.

2. 2. The liquefied gas carrier according to claim 1, wherein the rear mast light is installed on a tank cover corresponding to a cargo tank other than the rearmost cargo tank among the one or more tank covers.

3. 3. The liquefied gas carrier according to claim 1, wherein a vent mast extending from a tank cover positioned forward of the rear mast light is positioned to the right or left of the center of the tank cover in the left-right direction.

4. 4. A liquefied gas carrier according to claim 1, wherein the rear mast light is located forward of a vent mast extending from a tank cover on which the rear mast light is installed.

5. 5. A liquefied gas carrier according to any one of claims 1 to 4, wherein the rear mast light is explosion-proof.

6. 6. A liquefied gas carrier according to claim 1, wherein the rear mast light is mounted on the tank cover via the vent mast.

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