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Container Ship Types

The ship dimensions, such as the ship breadth, depend on the number of containers placed abreast on deck and in the holds. Thus, one extra container box abreast in a given ship design involves an increased ship breadth of about 2.8 meters. The average loaded container weighs about 10-12 tons but, of course, this may vary, so the modern container vessels are dimensioned for 12-14 dwt per TEU.

Containership capacity is normally expressed in Twenty-foot Equivalent Units (TEU), which is defined as the number of 20' x 8' x 8'6" containers it can carry; or, similarly, in Forty-foot Equivalent Units. Containerships vary considerably in size. Some of those serving major ports have capacities exceeding 5,000 TEU. Some recently built for feeder service (i.e., serving small outports from a major port) have capacities of 400 TEU or less.


The delivery in 1980 of the 4,100 teu Neptune Garnet was the largest container ship to date. Deliveries had now reached a level of 60-70 ships per year and, with some minor fluctuations, it stayed at this level until 1994, which saw the delivery of 143 ships. With the American New York, delivered in 1984, container ship size passed 4,600 teu. For the next 12 years, the max. container ship size was 4,500-5,000 teu (mainly because of the limitation on breadth and length imposed by the Panama Canal). The hull dimensions of the largest container ships, the so-called Panamax-size vessels, were limited by the length and breadth of the lock chambers of the Panama Canal, i.e. a max. ship breadth (beam) of 32.3 m, a max. overall ship length of 294.1 m (965 ft), and a max. draught of 12.0 m (39.5 ft). Panama Canal lock chambers are 305 m long and 33.5 m wide, and the largest depth of the canal is 12.5-13.7 m. The canal is about 86 km long, and passage takes eight hours.

The corresponding cargo capacity was between 4,500 and 5,000 teu. These maximum ship dimensions are also valid for passenger ships, but for other ships the maximum length is 289.6 m (950 ft). However, it should be noted that, for example, for bulk carriers and tankers, the term Panamax-size is defined as 32.2/32.3 m (106 ft) breadth, 228.6 m (750 ft) overall length, and no more than 12.0 m (39.5 ft) draught. The reason for the smaller length used for these ship types is that a large part of the world's harbors and corresponding facilities are based on this length. At present the canal has two lanes, but a possible third lane with an increased lock chamber size is under consideration in order to capture the next generation of container ships of up to about 12,000 teu.

Several maritime incidents during the early 1990's underscored the risk of serious injury or death, vessel loss, property damage, and environmental damage caused by improperly secured cargo aboard vessels. The most well-known incident occurred off the New Jersey coast in early 1992. During a voyage in bad weather, the M/V Santa Clara I lost 21 containers overboard, including 4 containers of the hazardous material, arsenic trioxide.

The Coast Guard convened a Board of Inquiry to investigate the M/V Santa Clara I mishap. The Board found that the container losses were caused by cargo securing failures related to bad weather and human error. Based on its findings, the Board recommended adopting the International Maritime Organization's (IMO) voluntary guidelines on cargo securing manuals as regulations in the International Convention for the Safety of Life at Sea, 1974 (SOLAS). The Commandant approved the Board's recommendation. With the support of other IMO member governments, the U.S. led a proposal to include new requirements for cargo securing manuals in SOLAS. These requirements were adopted as part of the 1994 amendments to SOLAS. These requirements are located in SOLAS Chapters VI/5.6 and VII/6.6.

Under SOLAS, all cargo vessels engaged on international voyages and equipped with cargo securing systems or individual securing arrangements must have a Flag State approved Cargo Securing Manual (CSM) by December 31, 1997. Under SOLAS and Executive Order 12234 -- which authorizes the Secretary to issue regulations that implement SOLAS--these requirements for a cargo securing manual apply to all U.S.-flag cargo vessels of 500 gross tons or more, engaged in international trade. Vessel types affected include general-cargo vessels, cellular containerships, roll-on/roll-off vessels, passenger/cargo vessels, supply vessels, bulk vessels capable of carrying non-bulk cargo, heavy lift ships, freight ships carrying packaged or break-bulk cargoes, and other similar vessels.


APL developed a new transportation net without using the Panama channel. This marked the creation of the new 'Post-Panmax' type. In 1996 the Regina Mærsk exceeded this limit, with an official capacity of 6,400 teu, and started a new development in the container ship market. Since 1996, the maximum size of container ships has rapidly increased from 6,600 teu in 1997 to 7,200 teu in 1998, and up to 8,700 teu in ships delivered in 1999. The vessels delivered or on order with a capacity of approx. 9,000 teu have exceeded the Panamax beam by approx. 10 m. The development of the post-panamax fleet has been dramatic; today 30% of the world's fleet, by capacity, is post-panamax

From the carrier perspective, the primary appeal of the mega ship is operating economy of scale. The operating cost of a 6,000 TEU vessel is not proportionally higher than that of a 4,000 TEU ship. However, viewed in terms of their impact on the larger transportation system, such vessels may actually impose higher costs. Problems with the Super Post-Panamax class of ship include the massive surge of containers discharged in a single port call; the challenge inherent in trying to fill a very large ship with cargo on a repetitive basis; and the expense involved in providing sufficient channel and berth depth, terminal area, gantry cranes of adequate size, and other items of equipment and infrastructure. Despite these concerns, over 50 orders for ships in this class were placed with shipyards in 1999 alone.

These ships are of a revolutionary design, answering the question "who needs hatchcovers?" In all but two forward holds, reserved for special and non-containerized cargo, traditional hatchcovers are missing. Instead, permanent cell guides run from the tank top to several levels above deck. As a result of the continuous cells, container twistlocks and lashings are not used. Speed of load/discharge is improved and container shifting is reduced. Taking into consideration that five cargo holds are exposed to rain and sea water, emphasis has been put on the development of the most efficient bilge system.

By 2000 the global container ship fleet numbered over 6,800 vessels. Over 71 percent of these are fully cellular, meaning they are "purpose-built" to carry ocean containers in specially constructed vertical slots. The capacity of this fleet was over 5.8 million Twenty-Foot Equivalent Units, or TEUs. While nearly three-quarters of the fleet by number consists of relatively small ships (specifically, those of under 1,000 TEU capacity), the "mega ship," or Super Post-Panamax vessel of 4,500 TEU and larger, is growing rapidly in prominence. By the end of 2001, about 10% of the global box ship fleet by capacity consisted of Super Post-Panamax ships.

At the beginning of the year 2004 there were already about 100 container ships with a capacity of 8,000 TEU in use. The Samsung shipyard builds a container ship with a capacity of 9.200 TEU, commissioning in 2005. Samsung delivered a 9,600 TEU ship in 2006. The increase in the maximum size of container ships does not mean that the demand for small feeder and coastal container ships has decreased. Ships with capacities of less than 2,000 teu account for more than 50% of the number of ships delivered in the last decade. Container ships compete with conventional reefer ships and, when it was delivered in 1996, the Regina Mærsk was the ship with the largest reefer capacity, with plugs for more than 700 reefer containers. There is almost no limit to the type of commodities that can be transported in a container and/or a container ship. This is one of the reasons why the container ship market is expected to grow faster than world trade and the economy in general. Some car manufacturers have already containerised the transport of new cars, and other car manufacturers are testing the potential for transporting up to four family cars in a 45-foot container.

All in all, the demand for transport capacity increases by 7-8% per year, and there is a fine balance between the yards' order books for container ships for delivery in 2001 and 2002, and the expected increase in the market (total 210 ships ~750,000 teu), i.e. no scrapping is envisaged. In total, the number of container ships delivered increased from 150 a year in 1994-1995 to 250 in 1998. As a consequence of the financial crises in the industrialised East Asian countries, deliveries decreased to 114 ships in 1999 and 115 in 2000. This shows how important the East Asian region is to the container ship market.

One train is physically limited to 240 40-foot containers. Therefore, about 10 double-stack trains would have to be arranged to move the inbound containers from one such 9000 TEU ship. Those problems can be solved through infrastructure improvement. Container vessels in the size range of 400-3,000 teu still hold a very important part of the freight market.

The larger the container ship, the more time is required for loading and unloading and, as the time schedule for a container ship is very tight, the extra time needed for loading/unloading means that, in general, larger container ships may have to sail at a proportionately higher service speed. The increase in ship size has been followed by a corresponding demand for higher design ship speeds. For ships in the size range of up to 1,500 teu, the speed is between 9 and 25 knots, with the majority of the ships (58%) sailing at some 15-19 knots. The most popular speed for the 1,500-2,500 teu ships is 18-21 knots, which applies to 70% of these ships. In the 2,500-4,000 teu range, 90% of the ships have a speed of 20-24 knots. 71% of the 4,000-6,000 teu ships have a speed of 23-25 knots. Finally, 80% of the ships that are larger than 6,000 teu have a speed of 24-26 knots. For the future ultra large container ships, a ship speed of 25-26 knots may be expected, whereas a higher ship speed would involve a disproportionately high fuel consumption.

In February 2005 it was announced that Lloyd's Register was to class the world's largest declared capacity container ships - four 10,000 teu vessels, to be built in Korea at Hyundai Heavy Industries for China Ocean Shipping Corporation (Cosco). The vessels will be delivered between late 2007 and mid-2008. Each of the ships will have a length overall of 349 meters, a breadth of 45.6 meters and a depth of 27.2 meters. Each ship will be fitted with a 12-cylinder 94,000 horsepower engine to enable a trading speed of 25.8 knots.

Lloyd's Register has an established track record of classing large container ships, including a series of 8,500 teu ships recently completed by Samsung Heavy Industries (SHI) for Canadian, Chinese and Greek owners. Other orders for large container ships to Lloyd's Register class include 9,200 and 9,600 teu ships at SHI, 8,400 teu ships at Daewoo Shipbuilding and Marine Engineering, 7,030 teu ships at Mitsubishi Heavy Industries and 6,400 teu ships at Hanjin Heavy Industries. The 10,000 teu container ships ordered by Cosco are the next step towards the 12,500 teu limit.

Suez-Max Ultra Large Container Ships (ULCS)

The Suez Canal canal is about 163 km long and 80-135 m wide, and has no lock chambers. Most of the canal has only a single traffic lane with several passing bays. It is intended to increase the depth of the canal before 2010 in order to capture the largest container ships to be built.

Suez-max investigations showed that in future, perhaps by 2010, Ultra Large Container Ships (ULCS) carrying some 12,000 teu containers can be expected. This ship size, with a breadth of 50 m / 57 m, and corresponding max. draught of 16.4 m / 14.4 m, may just meet the present Suezmax size.

For these very large vessels of the future, the propulsion power requirement may be up to about 100 MW/136,000 bhp. Investigations conducted by a propeller maker show that propellers can be built to absorb such high powers. Single-screw vessels are therefore still being considered, along with twin-skeg vessels (with two main engines and two propellers).

The ultra-large container ship (ULCS) study was initiated by Lloyd's Register, in association with Ocean Shipping Consultants Ltd, in 1999. The study commissioned by Lloyd's Register concluded that ultra-large container ships of up to 12,500 teu are entirely feasible and that the first of these vessels may be in service by 2010. The larger ships offer reduced cost, even taking into account the additional time spent in port. The calculations have been carried out on the assumption that a trading speed of 25 knots will be required across this entire range of ship sizes. This necessitates a twin-engine installation for ships of 10,000 teu and above. For the 18,000 teu container ship one might assume that an overall length of 470 m will be possible, assuming that the problem with the hull strength will be solved. This will reduce the ship draught and enable more harbors to handle such a large container ship.

Beyond 12,500 teu it is expected that container ship and container terminal design will have to undergo significant change. For container ships, this might include the addition of a second screw, with the added capital investment that this entails. The industry will probably see the first 12,500 teu ship ordered before 2010.

In September 2005 an innovative design study for a 13,000 TEU container ship was presented by Germanischer Lloyd and the Korean yard Hyundai Heavy Industries (HHI). The new ship design with two main engines and two propellers. All the relevant calculations have been carried out and the design completely approved by Germanischer Lloyd; the Korean yard is now accepting orders. The ship is 382 metres long and 54.2 metres wide, and has a draft of 13.5 m. The 6,230 containers below deck are stacked in 10 tiers and 19 rows, while the 7,210 deck containers are stowed in 21 rows. Powered by two 45,000 kW engines, the vessel's speed is 25.5 knots. The design study is characterized by two technical innovations: the cooperation partners decided on a twin drive configuration and the separation of deckhouse and engine room.

The question as to what propulsion powers and arrangements are needed to achieve the desired speed of 26 knots may be answered by diverse technical approaches: in the early phase of detailed calculations, not only the twin drive, but also the possibilities offered by one main engine, as well as one main engine with an additional pod drive, were considered. The cost estimate for the various drive configurations, never before done by a shipyard, indicated that a twin propulsion system was only negligibly more cost-intensive than the variant with only one main engine.

From the technical standpoint, the aspect of absolute safety is a major argument for the twin drive. In the event of an engine failure, the ship would remain manoeuvrable and could reach a safe harbour under its own steam. The main-engine and shaft sizes correspond to those of a 4,000 TEU carrier. More than 15 years of experience and smooth operation speak in favour of this size of propulsion unit. Engines and propellers of this size are in widespread use, making the maintenance and procurement of spare parts both easy and cost-effective.

On the other hand, the single-engine variant leads to several difficulties that have not been solved as yet. The output of a 14-cylinder engine is not enough to achieve the required speed, whereas a 16-cylinder engine would be too large. As regards propeller size, HHI believes that the maximum has been reached with a diameter of 9.5 m and a weight of 110 t. What is more, the single-screw design involves a great risk of cavitation; the extremely high shaft power also represents a hazard.

With a view to meeting the SOLAS requirements for bridge visibility on such a large ship, the design envisages the separation of deckhouse and engine room. The innovative arrangement of the deckhouse in the forward part of the ship permits an increase in container capacity and a reduction in ballast water. The international regulations on the protection of fuel tanks are also satisfied with this design, because they are located in the protected area below the deckhouse. Another welcome result of this innovation is reduced bending and increased stiffness of the hull.

Over a period of one and a half years, the cooperation partners Germanischer Lloyd and Hyundai Heavy Industries performed calculations for all components of the ship. The study investigated the layout of the ship, the number of containers and their stowage, the design of the fuel tanks, and also provided for strength analyses. Further aspects included slamming calculations, propulsion plants, engine room design and vibration analyses. In addition to towing experiments, tank model tests were also carried out at Hyundai in respect of parametric rolling, with the support of Germanischer Lloyd. At the same time, programs developed by Germanischer Lloyd were used to examine the behaviour of the ship in a seaway, especially parametric rolling. Moreover, exhaust emission tests were conducted to determine the optimum position for the funnels.

The production period for such a ship lies at 9 to 10 months. Owing to the great workload of the yard, delivery before 2009 will not be possible.

Many ports in America simply couldn't accommodate such vessels, except at great expense. And ports are differently endowed through the vagaries of geography or geology. Gulfport, Mississippi, for example, has about 36 feet of draft. New Orleans has about 40 feet, with all that sediment coming down the Mississippi. The Seattle approach channel, on the other hand, was glacier-carved; it averages 175 feet. Halifax, Nova Scotia, averages about 60 feet, Baltimore and Hampton Roads average about 50 feet, while New York/New Jersey presently averages 40 to 45 feet.

Thus, some U.S. ports will have an easier time of it when accommodating megaships, with the consequent potential for some reshuffling of rank among various North American ports. This would be very similar to another change that happened 40 years ago during the advent of containerization. Some people could make it--some people couldn't make it. San Francisco decided it didn't have the room to pursue containerization. It became a tourist waterfront and gave all of its cargo up to Oakland. Manhattan decided that it couldn't do it and gave it all to New Jersey.


Post-Suez-max nvestigations indicate that in about 10 years the ULCS will perhaps be as big as 18,000 teu, with a ship breadth of 60 m and a maximum draft of 21 m. Today, this ship size would be classified as a post-Suezmax ship, as the cross-section of the ship is too big for the present Suez Canal. It is claimed that the transportation cost per container for such a big ship may be about 30% lower than that of a typical 5,000-6,000 teu container vessel of today.


Malacca-max relfects the fact that a draft of 21 m is the maximum permissible draught through the Malacca Strait.

With the intended increase of the cross-section breadth and depth of the Suez Canal over the coming ten years, the 18,000 teu container ship will also be able to pass the Suez Canal. On the other hand, a future container ship with a draft of 21 m would require existing harbors to be dredged. Today, only the harbors of Singapore and Rotterdam are deep enough.

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Page last modified: 07-07-2011 12:42:59 ZULU