MacGREGOR covers 10,000 TEU seriesFour 10,000 TEU carriers ordered by COSCO from Hyundai Heavy Industries are the world largest container ships with a declared capacity, and benefit from MacGREGOR experience in designing hatch covers for larger and larger vessels of this type.MacGREGOR is providing hatch cover design and key components for four 10,000 TEU container ships ordered from Hyundai Heavy Industries in Korea by China Ocean Shipping (Group) Company (COSCO). The vessels will be delivered between late 2007 and mid-2008. The ships are 334.0m length bp, with a beam of 45.6m, a design draft of 13.0m and a speed of 25.8 knots. They are the first 10,000 TEU container carriers to be built in Asia, and the largest such ships with a declared capacity to be built anywhere. Eight of the 10 holds are located forward of the accommodation block, and there are two more aft. Each shipset of hatch covers comprises 78 lift-away panels; maximum weight of a panel is 40 tonnes. hatch opening No of panels 1F 12.6 x 20.6m 2 1A 12.6 x 35.3/30.6m 4 2F 12.6 x 40.9/36.1m 4 2A 10A 12.6 x 40.9m 4 each Container stack loads are: 1F: 100 tonnes (TEU), 122 tonnes (FEU) 1A 10A: 100 tonnes (TEU), 140 tonnes (FEU) Container shipping developments Container shipping business has grown by 8-10 per cent annually in recent years, points out Ilkka Lyytikinen, MacGREGOR sales manager for container ships. Therefore both the maximum size and the average size of container carriers grew bigger and bigger year by year. At the same time tough competition has driven a high demand to implement costs saving vessels. Costs per TEU are important in terms of both initial investment and operating costs. Not only is designing 10,000 TEU vessels a challenging task, but so also is designing their hatch covers. These must be reliable, carry heavy loads, and allow large free movements of the coamings. These are their main requirements. COSCO and Hyundai Heavy Industries are pioneers in taking the next step in this development of a new generation of container carriers. Background: container ship development In the early 1980s 2,700 TEU vessels were the largest container ships. The early 1990s saw the arrival of the first post-Panamax tonnage with a 40m beam and capacities up to 4,800 TEU. Under construction now are 10,000 TEU class ships, and design proposals for 12,000 TEU carriers have been completed. Third-generation Panamax tonnage built in the early 1980s with capacities around 3,000 TEU was typically fitted with longitudinal hold beams and twin hatches, says Kari Tirkkonen, senior naval architect in MacGREGOR Dry Cargo division. A significant difference to present designs was the small number of container layers on deck and the low stack weight (for example, 48 tonnes/20ft units and 60 tonnes/40ft units). Within almost the same ship dimensions and using triple hatches with longitudinal hold beams, the container capacity could be raised to around 4,400 TEU mainly by increasing the number of layers on deck. Stack weights were subsequently increased to 60 tonnes/20ft units and 90 tonnes/40ft units. By introducing open hatches without longitudinal girders allowing 11 rows in a hold capacity could be further increased to 4,700 TEU. This size is currently standard for Panamax ships rated at up to over 5,000 TEU and with stack weights up to 90 tonnes/20ft units and 120 tonnes/40ft units. Open-top Panamax ships offering easier loading and securing of containers have been built, but other features make them less attractive, Mr Tirkkonen says. Also introduced were six vessels with a 12 container in-hold arrangement with very narrow sides, which limits the length of the ship for strength reasons. The first post-Panamax ship, with a beam of around 40m and longitudinal girders and lashing bridges, was built in the early 1990s and rated for 4,500 TEU. With almost the same ship dimensions and open hatches, the capacity could be increased to around 4,800 TEU and then further up to 5,500 TEU or more with 16 containers abreast on deck. Such a size has evolved to become the standard post-Panamax vessel, Mr Tirkkonen says, with container loads normally of 90 tonnes/20ft and 120 tonnes/40ft units and increasing to 100 tonnes/20ft and 140 tonnes/40ft units. MacGREGOR has hatch cover designs for 144 container ships in size between 5,300 TEU and 8.300 TEU. Ships with beams of approximately 43m are also built with capacities ranging from 6,500 TEU to 8,200 TEU with 18 containers abreast on deck. MacGREGOR has hatch cover designs for 164 such container vessels. MacGREGOR has produced already hatch cover designs for 17 vessels having 45m-beam with capacities between 8,200 TEU and 10,000 TEU. There are a number of reasons for curbing further increases in size; although designs are not approaching the Suez-beam limit, their draft is now at the limit for the Canal passage. Hatch cover designs for container Ships Lift-away hatch covers with longitudinal joints are used on container ships; smaller ships (less than 700 TEU) can be fitted with covers having transverse joints or with folding covers. An open hold girderless design is normal for post-Panamax ships. The number of panels per hatch cover varies between three and five, the actual number depending on the allowed hoisting weight and owner preferences. With fewer panels, the hoisting weight is higher per panel but fewer hoists are necessary and the total weight is less. More panels mean the individual hoisting weight is reduced and the flexibility for partial loading and discharging the hold is better. In some ports the limited space available for panel stacking is favouring the more panels solution. The traditional weight limit for Panamax carrier hatch covers was 30.5 tonnes, the same as the maximum weight of a standard 40ft container. This enables 65 tonnes/20ft unit and 90 tonnes/40ft unit stack loadings; for bigger loadings the limit is higher. For 40m-beam post-Panamax tonnage the standard cover weight limit is 40 tonnes. For 43m and 45m beam ships the hoisting weight depends on the selected number of panels and their structural type. The logical limit would be 48 tonnes from the twin operation of two standard 20ft containers. For further information, please contact: Mr Ilkka Lyytikinen, Sales manager, Container Ships Tel. 358 2 4121 225 Fax: 358 2 4121 390 e-mail: ilkka.lyytikainen@macgregor-group.com  |
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