WO2013110822A1

WO2013110822A1 - A combined reefer and container ship

Info

Publication number: WO2013110822A1
Application number: PCT/EP2013/057903
Authority: WO
Inventors: Mark Robert JANSEN
Original assignee: Jansen Mark Robert
Priority date: 2012-04-18
Filing date: 2013-04-16
Publication date: 2013-08-01

Abstract

A refrigerated cargo ship comprising a hull (5), a weather deck (18), a front part (50), a rear part (60), a central part (70) and first, second and third cargo hold sections (20, 30, 40) is disclosed. The front part of the ship includes the first reefer cargo hold section and the rear part of the ship includes the second reefer cargo hold section. The central part of the ship includes a container hold, or an open top container hold, allowing for stowage of containers in cell guides from the ships tank top and upwards.

Description

A combined reefer and container ship

The present invention relates to a cargo ship providing high cargo capacity and flexibility through a unique arrangement and configuration of cargo hold sections. The sections, or cargo holding areas, constitute cargo holding sections configured for accommodating containers and, furthermore, cargo holding sections configured for accommodating palletized reefer cargo. The reefer cargo typically is stowed on decks or tween decks. The reefer cargo may constitute palletized cargo.

According to an initial part of a first aspect, the present invention relates to a cargo ship comprising a hull, a weather deck, a front part, a rear part, a central part, and first, second and third cargo hold sections, where: - The front part of the ship comprises the first cargo hold section. The first cargo hold section is thermally insulated, comprises cooling means and one or more tween decks. The first cargo hold section is configured for accommodating refrigerated cargo. The first cargo hold section is defined inter alia by the hull and the weather deck where the weather deck is provided at a first height above the baseline of the ship. The first cargo hold section further comprises access hatches or openings providing access to the first cargo hold section.

- The rear part of the ship comprises the second cargo hold section.

The second cargo hold section is thermally insulated, comprises cooling means and one or more tween decks. The second cargo hold section is configured for accommodating refrigerated cargo. The second cargo hold section is defined inter alia by the hull and the weather deck where the weather deck is provided at a second height above the baseline of the ship. The second cargo hold section further comprises access hatches or openings providing access to the second cargo hold section.

According to a second aspect, the present invention relates to a method of converting a refrigerated cargo ship into a refrigerated cargo ship comprising a container hold section or an open top container hold section. The method includes the step of, in-between two or more reefer hold sections and essentially amidships, interposing one or more pure container hold sections or one or more open top container hold sections. The step of interposing may be performed during new building or as a retrofit.

An open top container hold, for the purpose of this application, refers to a cargo hold which is designed for the carriage of containers and which is constructed like an open "U". The open top container hold typically includes a double bottom and above this, high-sided erections without hatch covers.

The expression "weather deck" is throughout this specification intended to denote any deck exposed to the outside, i.e. a weather deck within the meaning of this specification forms an upwardly oriented closure of a ship's hull.

The expression "main deck" is throughout this specification intended to denote a deck extending between the forward and aft ends of a ship. The main deck may constitute the highest water tight deck of the ship, which may also be denoted "upper deck" or in designs wherein the main deck is exposed to weather, the main deck may be denoted as "weather deck".

The expression "aft", "after" or "rear" is throughout this specification intended to denote a portion of a ship lying behind the middle portion of the ship. The expression "fwd", "front" or "forward" is throughout this specification intended to denote a portion of a ship lying in front of the middle portion of the ship. Background

According to common shipbuilding practise, the rear part of cargo ships typically comprises a superstructure including a navigating bridge and means necessary for the propulsion of the ship including fuel tanks and the like. The front part of the ship comprises the stem and often also store rooms and the like.

The central part of the ship comprises the cargo hold or holds, which is constructed in accordance with the specific types of goods to be transported. The hold or holds may thus be constructed specifically for the transport of one or more specific types of goods such as containers or palletized goods, etc.

Particularly in the past, possibilities of utilizing cargo ships for carrying com- binations of the above-mentioned types of goods were very limited.

Most of todays refrigerated cargo ships, or reefer ships, are based on the concept of providing a main deck or weather deck adapted for stowage of containers and other lift-on and lift-off cargoes, while, below deck, a plurality of tween decks are arranged in insulated and cooled sections configured for stowage of palletized goods.

The above concept is widely recognized and used, however the concept entails several drawbacks, some of them are: - That the ship operates with unsuitable resulting stability in case of the ship being loaded with gravity wise inhomogeneous cargo configurations, e.g. when only one type of cargo is transported, - That the concept allows for only limited stowage of deck cargo such as containers and the like, and

- The stowage of containers is time consuming and prone to cargo

damage as the containers are stowed on deck without cell guides.

As a result of the ship being inappropriately loaded, e.g. when the ship is "top heavy" due to stowage of containers on deck, and consequently in conditions where the resulting centre of gravity of the cargo lies too high, the ship is forced to carry a substantial quantity of water ballast in order to outbalance the inappropriate centre of gravity of the cargo.

Prior art fails to suggest a solution wherein it is possible to achieve optimum flexibility and capacity with respect to the configuration of combined reefer/container ships. In particular, the conventional layout of classical re- frigerated cargo ships has, due to the above stability wise and space wise drawbacks, set a limit to the quantity of containers to be carried.

The European Patent No. 10 35 998 discloses a cargo ship wherein a refrigerated cargo hold section accommodating a relatively large number of tween decks with a small free height is arranged essentially amidships. A second cargo in the form of containers is stowed aft and forward of the refrigerated cargo hold section in container hold sections. The refrigerated cargo hold section extends from the tank top of the ship to a height above the weather deck. The container holds, arranged aft and forward of the refrigerated cargo hold section, also extend from the tank top to a height above the weather deck. The object of the above European Patent is to set forth a refrigerated cargo ship being able to carry a high number of containers while minimizing or eliminating the need to carry water ballast. A ship according to European Patent No. 10 35 998 is considered an expensive and complex ship e.g. as the refrigerated cargo hold section is accessed via one or more complex side loaders, and further, as the container hold sections are disposed in front and rear parts of the ship respectively, the container holds should, for protective reasons, be provided with hatch covers which greatly increases cargo han- dling efforts.

Brief description of the invention

It is an object of the present invention to:

- Provide an improved cargo ship with little or no stability nuisances,

- Provide an improved ship configured for carrying palletized cargo in one or more dedicated refrigerated cargo holds while allowing greater amounts of the other goods, such as containers, to be transported simultaneously,

- Provide an improved reefer cargo ship allowing for stowage of containers in one or more container holds, or open top container holds, while also allowing for carriage of palletized goods in dedicated refrigerated cargo holds, and

- Provide an improved reefer cargo ship configured for carrying a large amount of containers which eliminates or substantially reduces the re- quirement for the ship to load ballast water. According to the remaining part of the first aspect of the present invention, the above objects are met by providing a ship according to the introductory part of this specification wherein the central part of the ship comprises the third cargo hold section. The third cargo hold section constitutes a container hold section provided with cell guides defining vertical cells for accommodating containers. The third cargo hold section is arranged essentially amidships of the ship, in between the first and the second cargo hold sections. The third cargo hold section inter alia is defined by a longitudinally extending hatch coaming extending at least 0.5 m above the weather deck.

A ship configured according to the above allows for refrigerated and/or palletized goods to be stowed under deck in the first and second cargo hold sections as well as a considerable number of containers to be stowed from the ship's tank top and upwards in cell guides.

In particular, it is rendered possible to transport or carry containers and no palletized cargo without the ship being forced to operate under unfavourable stability and/or loading conditions. The favourable loading conditions eliminate, or significantly reduce, the need to carry and transport water ballast whereby fuel saving as well as savings on environmental impacts is evident.

A ship designed according to the above enables a ship owner or operator to obtain greater earnings per voyage inter alia as a greater part of the ship's deadweight is freed thereby increasing payload.

The deadweight is the total weight that a ship is allowed to carry. The deadweight includes cargo, water ballast, fuel, stores and crew etc. Conclusively, a ship constructed in accordance with the present invention will be able to operate without palletized cargo stowed under deck and with a large amount of containers stowed relatively low against the keel or tank top in the central and third cargo hold section. As the vertical centre of gravity of the containers will lie relatively low compared with the vertical centre of gravity of containers stowed on a face of a weather deck, the ship according to the present invention will not be required to load water ballast in order to bring the resulting vertical centre of gravity of the deadweight down. By this a highly improved metacentric height (GM) is obtained by payload only.

The metacentric height (GM) is a measurement of the initial static stability of a floating body such as a ship. It is calculated as the distance between the centre of gravity of the ship and its metacentre. A larger metacentric height (GM) implies greater initial stability against overturning. Metacentric height also has implication on the natural period of rolling of a hull, with very large metacentric heights being associated with shorter periods of roll which are uncomfortable for passengers or crew and may damage cargo etc. Hence, a sufficiently high but not excessively high metacentric height is generally considered ideal for ships.

As per the above, in conventional refrigerated cargo ships, when the second cargo in form of containers generally is carried on or above the weather deck; the vertical centre of gravity in these ships is unfavourable when sailing without cargo below the weather deck. Further, on deck stowage of the contain- ers may lead to an unfavourable longitudinal centre of gravity of the containers as the containers typically is stowed high in the aft part of the ship and relatively low in the forward part of the ship. The difference in stacking or stowage height is due to requirements of visibility from the navigation bridge. As the relatively heavy container cargo is, in a ship according to the present invention, stowed essentially amidships, the longitudinal centre of gravity of the cargo will remain virtually unchanged regardless of the number of containers stowed.

Prior art holds examples of refrigerated cargo ships configured to accommo- date containers below the weather deck, i.e. in its reefer holds, however this is only possible upon removal of hatches and the like, and as the containers are stowed in the "pallet space" below the weather deck, these ships do not offer a high degree of flexibility for the ship owner or operator. According to one embodiment, the coaming, or the hatch coaming, of the third cargo hold section may extend at least 1 meter above hatch coamings of the access hatches of the first and second cargo hold sections.

According to one embodiment, the length of the third cargo hold section may be at least 15 % of the length (LOA or LPP) of the ship.

According to one embodiment, a navigating bridge may be arranged or disposed in the rear part of the ship. According to one embodiment, crew accommodation quarters may be arranged or disposed, possibly below the navigating bridge, in the rear part of the ship.

According to one embodiment, the third cargo hold section may be ventilated by means of air ducts arranged in the forward and/or aft end and/or in the middle of the central part of the ship. Further, the third cargo hold section may comprise power outlets for refrigerated containers.

According to one embodiment, the hatch coamings of the first and the sec- ond cargo hold sections may at least partially define the access hatches of the first and the second cargo hold sections. The access hatches of the first and the second cargo hold sections may be disposed closer to a central longitudinal axis of the ship than the hatch coaming, or access hatches, of the third cargo hold section. According to one embodiment, the hull of the ship may constitute a double hull comprising an outer shell and inner lining. The inner lining may contribute substantially to the longitudinal strength of the hull and the inner lining may, in the region of the first and second cargo hold sections, be arranged in a first distance from a central and longitudinal plane of the hull. The first distance may be less than a second distance between the central and longitudinal plane of the hull and the lining arranged in the region of the third cargo hold section.

According to one embodiment, the lining arranged in the region of the third cargo hold section may extend, or may be continued as one or more structural members, longitudinally along the inner lining, in the region of one or both of the first and the second cargo hold sections.

Brief description of the drawings

Figure 1 schematically illustrates a sectional side view of a ship according to an aspect of the present invention.

Figure 2 schematically illustrates a sectional top view of a ship according to an aspect of the present invention.

Figure 3 schematically illustrates a transverse sectional view through the first cargo hold section of a ship according to an aspect of the present invention. Figure 4 schematically illustrates a transverse sectional view through the third cargo hold section of a ship according to an aspect of the present invention. Detailed description of the invention with reference to the accompanying figures

The invention will in the below be explained in detail with reference to an embodiment as shown in the figures.

Figure 1 shows a longitudinal section through a ship according to one aspect of the present invention. Numerals 20 and 30 respectively refers to first and second cargo hold sections disposed in the front part 50 and the rear part 60 of the ship 1 respectively. Numeral 40 refers to the third cargo hold section disposed in the central part 70 of the ship 1 .

The third cargo hold section 40 may, as shown in figures 1 and 2, be divided into two or more sub-sections 26 (figure 2). The weather deck 18, which forms an upwards closure of a part of the hull 5, may serve to support not shown deck cargo above the first and second cargo hold sections 20, 30. The deck cargo may constitute containers stacked on top of each other and secured, or lashed, to the weather deck 18. The stacking height of the containers will usually be limited partly as a result of lack of stability of the ship against heeling and partly by International maritime rules, according to which a line of sight from the navigating bridge 230 must reach the surface of the sea at a certain distance from the stem. It is clear that the stability of the ship will be affected considerably if the cargo hold sections 20 and 30 are empty and cargo such as containers are stowed high on deck above the cargo hold sections 20, 30. Cargo ships, such as refrigerated cargo ships, often sail one way with one type of cargo only and return with a second cargo only. In load conditions wherein no cargo is stowed under deck and cargo such as containers are stowed on deck, the resulting centre of gravity of the cargo often is too high. This high centre of gravity requires that the ship loads water ballast in order to compensate for this high centre of gravity. Compensation is accomplished by loading ballast water onto one or more ballast tanks 125 (figures 3 and 4). The ballast water is, in some conditions, occupying as much as 50% of the loading capacity, or the deadweight, of the ship. From the above, it is clear that on a voyage, wherein the ship carries containers only, it is only possible to carry a relatively small number of containers, which must be stacked very low on the weather deck 18. Seen from an economic point of view, this situation is undesirable of course, as it reduces the earnings of the ship owner unnecessarily.

As can be seen in figures 1 and 2, the ship's cargo hold layout may include three cargo hold sections, and one or more of the sections may be divided into subsections. The sections are:

A first cargo hold section 20 arranged in the forward part 50 of the ship 1 . The first cargo hold section may constitute a classic reefer hold section provided with gratings or configured for grating-less air distribution. The first cargo hold section 20 may include one or more tween decks 21 and one or more not shown tween deck hatch covers, - A second cargo hold section 30 arranged in the rear part 60 of the ship 1 . The second cargo hold section may constitute a classic reefer hold section provided with gratings or configured for grating-less air distribution. The second cargo hold section 30 may include one or more tween decks 31 and one or more not shown tween deck hatch covers, and

- A third cargo hold section 40 arranged in the central part of the ship 70. The third cargo hold section is, in accordance with the first aspect of the present invention, disposed in the central part 70 of the ship and configured a container hold provided with cell guides 42, see figure 4. Arranging the third cargo hold section 40 in the central part 70 of the ship is particularly advantageous as the container hold is protected from high seas as well as spray water etc.

The container holds may constitute open top container holds such as shown in the figures. According to a not shown embodiment, the container holds may constitute classic container holds provided with hatch covers. The hatch covers may be configured for supporting cargo above the hatches.

As can be seen in figures 1 , 2 and 4 the third cargo hold section 40 may extends above and below the weather deck 18 and/or the main deck 6.

The rear part 60 of the ship 1 includes space 10 for machinery incl. machin- ery for propulsion etc. and the second cargo hold section 30.

The front part 50 of the ship 1 comprises the stem of the ship 1 and, as mentioned, the first cargo hold section 20. The first cargo hold section 20, and also the second cargo hold section 30, extend upwardly, possibly up to, or above, the weather deck 18, either from the ship's 1 tank top 7, directly or indirectly, or from a deck above the tank top 7.

The weather deck 18 and/or the main deck 6 may, above the first and second cargo hold sections 20, 30, comprise access hatches 20', 30' providing access to the hold sections for vertical stowage of goods by means of a crane or equivalent.

The third cargo hold section 40 may be provided with cell guides 42 for verti- cal guidance of containers 1 10. The cell guides 42 may or may not be provided with not shown container stoppers. Container stoppers reduce the stack weight for or on the lowermost containers and allow the operator to stow general cargo such as break bulk below containers resting on stoppers in the cell guides 42.

Moreover, main deck 6, as well as the weather deck 18, in the front part 50 and the rear part 60 of the ship 1 may be arranged at different levels above the base line 1 1 of the ship 1 . As per the above, the ship 1 includes a central part 70 having a third cargo hold section 40 and the longitudinal extent of the third cargo hold section 40 preferably constitutes at least 15 % of the overall length 2 of the ship 1 (LPP or LOA). The width of the third cargo hold section 40 may correspond essentially to the width of the ship 1 ; however it will be possible to interpose means for ventilation, sprinkling, side tanks or voids etc. between the sides of the ship 1 and the third cargo hold section 40. In certain embodiments, and possibly according to requirements of rules and regulations relating to the intact and damage stability of the ship 1 , it may be desired or necessary to arrange watertight transverse and/or longitudinal bulkheads dividing the third cargo hold section 40 into sub sections.

The third cargo hold section 40 may be delimited directly or indirectly in a longitudinal direction by means of transverse walls or bulkheads 12, 13 and in a vertical direction by the tank top 7.

Further, the third cargo hold section 40 may be arranged with means for lighting, fire fighting, bilge dewatering and ventilation etc. corresponding to the customary shipbuilding practice and regulatory requirements associated with a container hold or an open top container hold.

The third cargo hold section 40 may accommodate means for ventilating the cargo hold section. The ventilating means (not shown) may take any form however a preferred embodiment comprises ducting means arranged in the forward and/or aft end and/or in the middle of the central part 70 of the ship 1 .

The hatch coaming 14, or the coaming top, of the third cargo hold section 40, which in this section may constitute the inner lining 47, or the inner lining 47 may, as indicated in figure 4 be continued as one or more structural members 15, longitudinally along the inner lining 27, 37 or in the vessel's shell in the region of one or both of the first and the second cargo hold sections 20, 30.

Although not shown in the figures, the third cargo hold section 40 may constitute one or more container hold sections provided with:

- Cell guides defining vertical cargo cells configured for supporting

stacked containers, and

- Hatch covers defining upwards closure of the container hold sections.

The hatch covers may or may not be configured for supporting cargo. According to one embodiment, a cargo ship 1 comprising a hull 5, a weather deck 18, a front part 50, a rear part 60, a central part 70, and first, second and third cargo hold sections 20, 30, 40 is disclosed wherein:

- The front part 50 of the ship 1 comprises the first cargo hold section 20) and the first cargo hold section 20 is thermally insulated, comprises cooling means, one or more tween decks 21 and is configured for accommodating refrigerated cargo 100. The first cargo hold section 20 is defined inter alia by the hull 5 and the weather deck 18 where the weather deck 18 is provided at a height 22 above a baseline 1 1 of the ship 1 . The cargo hold section 20 further comprises access hatches 20' or openings providing access to the first cargo hold section 20.

- The rear part 60 of the ship 1 comprises the second cargo hold section 30. The second cargo hold section 30 is thermally insulated, comprises cooling means, one or more tween decks 31 and is configured for accommodating refrigerated cargo 100. The second cargo hold section 30 is defined inter alia by the hull 5 and said weather deck 18 where the weather deck 18 is provided at a height 2 above a baseline 1 1 of the ship 1 . The second cargo hold section 30 further comprises access hatches 30' or openings providing access to the second cargo hold section 30.

- The central part 70 of the ship 1 comprises said third cargo hold section 40. The third cargo hold section is configured for accommodating containers 1 10. The third cargo hold section 40 is arranged in between the first and said second cargo hold sections 20, 30 and essentially amidships of the ship 1 . The third cargo hold section 40 constitutes an open top container hold inter alia defined by a coaming 14 extending, above the weather deck 18, at least a height 24 of 0.1 one of the heights 23 or 22 above the weather deck 18.

Although not shown in the figures, the first and second cargo hold sections 20, 30 may be provided with not shown side loading systems configured for conveying palletized cargo sideways into the ship. The side loading system may comprise external and/or internal elevator systems. The external elevator system may be configured for elevating cargo outside the ship and the internal elevator system may be configured for elevating the cargo between a cargo handling platform in the side loader and the tween decks 21 . In embodiments wherein the first and second cargo holding sections is provided with side loading systems, it may be preferred to not to provide the first and second cargo holding sections 20, 30 with access hatches 20', 30'. The application and combination of features and solutions presented by the present invention are not limited to the presented embodiments. One or more features of one embodiment can and may be combined with one or more features of other embodiments, whereby not described but valid, embodiments of the present invention may be obtained.

The terms "including/comprises/comprising/comprised of when used in this specification incl. claims is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Claims

Claims:

1 . A cargo ship (1 ) comprising a hull (5), a weather deck (18), a front part (50), a rear part (60), a central part (70), and first, second and third cargo hold sections (20, 30, 40), where:

- said front part (50) of said ship (1 ) comprises said first cargo hold section (20), said first cargo hold section (20) is thermally insulated, comprises cooling means, one or more tween decks (21 ) and is configured for accommodating refrigerated cargo (100), said first cargo hold sec- tion (20) is defined inter alia by said hull (5) and said weather deck

(18) where said weather deck (18) is provided at a first height (22) above a baseline (1 1 ) of said ship (1 ), and said first cargo hold section (20) further comprises access hatches (20') or openings providing access to said first cargo hold section (20),

- said rear part (60) of said ship (1 ) comprises said second cargo hold section (30), said second cargo hold section (30) is thermally insulated, comprises cooling means, one or more tween decks (31 ) and is configured for accommodating refrigerated cargo (100), said second cargo hold section (30) is defined inter alia by said hull (5) and said weather deck (18) where said weather deck (18) is provided at a second height (23) above a baseline (1 1 ) of said ship (1 ), and said second cargo hold section (30) further comprises access hatches (30') or openings providing access to said second cargo hold section (30), characterized in that said central part (70) of said ship (1 ) comprises said third cargo hold section (40), said third cargo hold section (40) constitutes a container hold section provided with cell guides (42) defining vertical cells for accommodating containers, said third cargo hold section (40) is arranged essentially amidships of said ship (1 ) in between said first and said second cargo hold sections (20, 30), said third cargo hold section (40) inter alia is defined by a longitudinally extending hatch coaming (14) extending at least 0.5 m above said weather deck (18).

2. A cargo ship according to claim 1 , wherein said hatch coaming (14) of said third cargo hold section (40) extends at least a height (24) of 0.1 one of said first height (22) or said second height (23).

3. A cargo ship according to any one or more of the foregoing claims, wherein said hatch coaming (14) of said third cargo hold section (40) extends at least 1 meter above hatch coamings (35) of said access hatches (20', 30') of said first and second cargo hold sections (20, 30).

4. A cargo ship according to any one or more of the foregoing claims wherein a length (41 ) of said third cargo hold section (40) is at least 15 % of a length (2) of said ship (1 ).

5. A cargo ship according to any one or more of the foregoing claims wherein a navigating bridge (230) is arranged in said rear part (60) of said ship (1 ).

6. A cargo ship according to any one or more of the foregoing claims wherein crew accommodation quarters (231 ) is arranged in said rear part (60) of said ship (1 ).

7. A cargo ship according to any one or more of the foregoing claims wherein said third cargo hold section (40) is ventilated by means of air ducts arranged in the forward and/or aft end of said central part (70) of said ship (1 ) and wherein said third cargo hold section (40) comprises power outlets for refrigerated containers.

8. A cargo ship according to any one or more of the foregoing claims wherein said hatch coamings (35) of said first and said second cargo hold sections (20, 30) at least partially define said access hatches (20', 30') of said first and said second cargo hold sections (20, 30), said access hatches (20', 30') are disposed closer to a central longitudinal axis of said ship (1 ) than said coaming (14) of said cargo hold section (40).

9. A cargo ship according to any one or more of the foregoing claims wherein said hull (5) constitutes a double hull comprising an outer shell and inner lining (27, 37, 47) wherein said inner lining (27, 37, 47) contributes substantially to the longitudinal strength of said hull (5) and wherein said inner lining (27, 37), in the region of said first and second cargo hold sections (20, 30), is arranged in a first distance from a central and longitudinal plane (120) of said hull (5) which is less than a second distance between said central and longitudinal plane (120) of said hull (5) and said lining (47) arranged in the region of the third cargo hold section (40).

10. A cargo ship according to claim 9, wherein said lining (47) arranged in the region of the third cargo hold section (40) extends, or is continued as structural members (15), longitudinally along said inner lining (27, 37), in the region of said first and second cargo hold sections (20, 30).

1 1 . A cargo ship according to any one or more of the foregoing claims wherein said third cargo hold section (40) constitutes an open top container hold section.