Triple E-class container ship

• 
  Section of a Triple E-class ship, under construction
• 
  Mærsk Mc-Kinney Møller, passing through the Suez Canal
• 
  Manila Maersk inbound Hamburg, Germany in June 2018
• 
  Monaco Maersk of the 2nd generation (2018 in Hamburg)

• Capacity: 18,270 TEU[49][50]
• Length: 399.2 metres
• Draft: 14.5 metres
• Beam: 59 metres
• Height: 73 metres
• Optimum speed: 19 knots (35 km/h)
• Top speed: 25 knots (46 km/h)[51]
• Deadweight: 165,000 tonnes
• In the first 10 vessels engines are twin MAN 8S80ME-C9.2 engines, 8-cylinders, 800 mm bore, 3450 mm stroke, rated at 29.7 MW @ 73 rpm each, with fuel consumption of 168 g/kWh[52] (80 m³ (21,200 US gal) per day)[53]
• Propellers: Twin propellers, with 4 blades, 9.8 m in diameter[54]

Unlike conventional single-engined container ships, the new class of ships has a twin-skeg design: it has twin diesel engines, each driving a separate propeller. Usually, a single engine is more efficient,[12] but using two propellers allows a better distribution of pressure, which increases the propeller efficiency more than the disadvantage of using two engines.[55]

The engines have waste heat recovery (WHR) systems; these are also used in 20 other Mærsk vessels including the eight E-class ships. The name "Triple E class" refers to three design principles: "Economies of scale, energy efficiency, and environmental impact improvement".[49]

The twin-skeg principle also means that the engines can be lower and further back, allowing more room for cargo. Maersk requires ultra-long stroke two-stroke engines running at 80 rpm (versus 90 rpm in the E class);[56] but this requires more propeller area for the same effect, and such a combination is only possible with two propellers due to the shallow water depth of the desired route.[13][54]

A slower speed of 19 knots is designed, compared to the 23–26 knots of similar ships.[13] The top speed would be 25 knots, but steaming at 20 knots would reduce fuel consumption by 37%, and at 17.5 knots fuel consumption would be halved.[51] These slower speeds would add 2–6 days to journey times.[57]

The various environmental features are expected to cost $30 million per ship, of which the WHR is to cost $10 million.[12] Carbon dioxide emissions, per container, are expected to be 50% lower than emissions by typical ships on the Asia-Europe route[58] and 20% lower than Emma Maersk.[59] These are the most efficient container ships per TEU in the world. A cradle-to-cradle design principle was used to improve scrapping when the ships end their life.[60]

The Madrid Maersk and subsequent ships in the series use electric motor-generator sets to improve operation.[61]

2013 comparison between the longest ships for different types of vessels, Mærsk Mc-Kinney Møller being the longest container ship at that time

The ships were the longest in the world.[62][63] They have since been surpassed by other container ships, like the MV Barzan, exactly 400 m (1,312 ft) long. The Triple E series and its competitors often leapfrog each other for capacity as the types are updated with new ships larger than their sisters. For a while, Madrid Maersk with 20,568 TEU had the world's largest capacity until superseded by the 21,413 TEU OOCL Hong Kong.[64]

The hull is more 'boxy' with a U cross-section compared to the V-shape of Maersk's E class; this allows more containers to be stored at lower levels so, while the Triple E class is only 3 m (9.8 ft) wider and 4 m (13 ft) longer, it can carry 2,500 (16%) more containers. The Triple E class can carry 23 rows of containers compared to 22 of the E class, which makes better use of the reach of current terminal cranes.[12]

The deckhouse is relatively further forward, whilst the engines are to the rear; similar to CMA CGM's Explorer class of containerships, also built by Daewoo.[65] The forward deckhouse allows containers to be stacked higher in front of the bridge, further increasing capacity while maintaining forward visibility sufficient to comply with SOLAS regulation V/22.

The Triple E-class vessels are operated by a crew of 13, while the even larger Globe class requires 31 on board.

When the class was ordered, no port in the Americas could handle ships of their size.[66] However, the following suitable ports include Shanghai, Ningbo, Xiamen, Qingdao, Yantian, Hong Kong, Tanjung Pelepas, Singapore, and Colombo in Asia, and Rotterdam, Gothenburg, Wilhelmshaven,[67] Bremerhaven, Southampton, London Gateway, Le Havre, Felixstowe, Gdańsk, Antwerp, and Algeciras in Europe. The ships will be too large for the New Panamax-sized locks on the Panama Canal,[66] and their main route is expected to be Asia-Europe (through the Suez Canal).[68] The draft of the Triple E class is 14.5 metres (48 ft), less than the SuezMax requirement of 55.9 ft (17.0 m) at 59 m (194 ft) beam.[69] Handling equipment at ports was the main constraint on size, rather than the dimensions of canals or straits.[12] The container port handling speed can be 29 moves per hour in Tanger-Med,[70] or 37 in Rotterdam (215 per ship).[71] Anchor and mooring winch systems are being supplied by TTS Marine.[72]