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Size comparison of containerships

September 30, 2006

Germanischer Lloyd and HHI unveil 13,000 TEU containership

Germanischer Lloyd and Hyundai Heavy Industries (HHI) are showing just how big container carriers will be in the near future.

Mr D.S. Cho, Executive Vice President of HHI, and Jan-Olaf Probst, Ship Type Manager for Container Ships at Germanischer Lloyd this week presented an innovative design for a 13,000 TEU containership with two main engines and two propellers.

All the relevant calculations have been carried out and the design has completely approved by Germanischer Lloyd.

HHI is now accepting orders. Construction time for the ship would be nine to 10 months, but the yard's current order backlog means that the earliest delivery available would be 2009.

The ship is 382 m long and 54.2 m 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 features two technical innovations: a twin drive configuration and the separation of deckhouse and engine room.

To achieve the desired speed of 26 knots several technical approaches were considered 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 previously performed 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 maneuvereable and could reach a safe harbor under its own power.

The engines and shafts would have sizes corresponding to those of a 4,000 TEU carrier.

More than 15 years of experience and smooth operation favor 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 presents several difficulties that have not yet been resolved.

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 propeller size 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.

To meet SOLAS requirements for bridge visibility on such a large ship, the design envisages the separation of deckhouse and engine room.

The 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, since 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, 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 considerations 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. Exhaust emission tests were conducted to determine the optimum position for the stacks.

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