A straight-14 engine or inline-14 engine is a fourteen-cylinder internal combustion engine with all fourteen cylinders mounted in a straight line along the crankcase. A straight-14 is a very long engine, and therefore only suitable for marine installations in large ships.
The only engine of this type known to have been built is a member of the Wärtsilä-Sulzer RTA96-C family. It is the world's most powerful combustion engine and is mounted in Emma Mærsk, the world's largest container ship. It is of two-stroke diesel engine configuration. The engine became well known due to photos taken at the Aioi Works in Japan, which subsequently spread through blogs.
The 14-cylinder version of this modular engine produces 80,080 kilowatts (107,390 hp) and displaces 25,340 litres (1,546,000 cubic inches), with a 960 mm (38 in) cylinder bore and 2,500 mm (98 in) piston stroke. The engine is 27.3 metres (90 ft) long, 13.5 m (44 ft) high, and weighs 2,300 tonnes (2,264 long tons; 2,535 short tons).
If built, the 14-cylinder variant of the MAN B&W K108ME-C would be even larger at nearly 33 metres (108 ft) long, and over 2,800 tonnes (2,800 long tons; 3,100 short tons), and more powerful at 97,300 kilowatts (130,500 hp).