How has Maersk achieved this seemingly impossible feat? The answer lies in the Triple-E’s expanded inside cavity, which gives the ship 16 percent greater capacity than Maersk current largest vessel – the E-class (Emma Maersk). The new design adds room for an extra 2,500 containers, despite relatively little change in the length and width.
Container capacity and greater fuel efficiency – the initial brief called for it to be at least 30% more efficient than competitors’ vessels – were the two main drivers behind the Triple-E. So, to improve upon the design of E-class vessels – the current benchmark in both of these categories – Maersk established a different set of performance parameters.
The ship was designed with a wider hull and more bulbous bow to accommodate 18,000 20-foot containers. Container capacity was the top priority, which meant that a wider hull was essential. The V-shaped hull of E-class vessels is sleek and limits resistance in the water, but it also limits space for contain¬ers towards the bottom of the ‘V’. Therefore, the Triple-E boasts a more U-like hull form, sometimes referred to as a ‘bath tub’ shape. An extra row of containers was added to the Triple-E as well, giving it 23 rows across its width, compared to the E-class’s 22. The more spacious hull and extra row provides room for an extra 1,500 containers.
More container space was created by moving the navigation bridge and accommodation five bays forward and the engine room and chimney six bays back in what is called a ‘two-island’ design. With the more forward navigation bridge, 250 additional containers can be stacked higher in front of the bridge without losing visibility. And 750 more containers can now fill the space behind the bridge above deck and below deck using the space created by the engine room’s position further to the back of the vessel.
The Triple-E’s greater bulk cre¬ates more resistance in the water than Emma’s sleeker V-shape, which would normally be less desirable – but not in this case. Its dual engine is limited to a top speed of 23 knots and can run as low as 80 revolutions per minute (rpm), compared to Emma’s 25 knots and 90 rpm. This means the Triple-E’s operational sweet spot – the speed at which the vessel is most fuel efficient – is lower than Emma’s. The pleasing result is that the increased resistance caused by the bulkier design has no significant impact on the Triple-E’s greater overall effi¬ciency.
When the first Triple-E vessel is delivered in June 2013, Maersk Line will have the capacity to transport sufficient containers – or removal vans – to fully furnish 18,000 family apartments in one go.
FACTS: Full-bodied hull boosts capacity
- The dimensions of Maersk Line’s new Triple-E container vessels offer only a few metres extra length and width over the Maersk E-class of ships, yet the capacity is 16 per cent greater – rising from 15,500 to 18,000 containers
- The space for extra 2,500 containers is a result of the Triple-E’s ingenious design. Only a few metres wider across the beam than Maersk E-class (59 compared to 56 metres) the Triple-E boasts an extra row of containers (23 instead of 22), which gives an added capacity of some 1,000 containers
- The Triple-E container vessels are more full-bodied than the Maersk E-class. Along with the separation of the traditional superstructure of container vessels – the bridge, accommodation block and engine room – into two units, this has freed up the majority of the midship enabling better use of the hull. This gives an added capacity of 500 containers
- With the navigation bridge now in a more forward position, this allows for higher container stacks above deck without restricting visibility. This gives an added capacity of some 250 containers
- And, with the navigation bridge moved forward, containers can be stacked higher midship behind the bridge. Along with moving the engine room further back to allow for more stacks in the holds, this gives an added capacity of some 750 containers