A straight-nine engine or inline-nine engine is a straight engine

Straight engine

Usually found in four- and six-cylinder configurations, the straight engine, or inline engine is an internal-combustion engine with all cylinders aligned in one row, with no offset...

 with nine cylinder

Cylinder (engine)

A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...

s. Straight-nine engines are usually diesel engine

Diesel engine

A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

s used for ship

Ship

Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

 propulsion. Rolls-Royce Marine Engines

Rolls-Royce Marine Diesel Engines

Rolls-Royce Marine Diesel Engines are manufactured by Rolls-Royce plc and cover five ranges of diesel engines for the marine sector.There are three "Bergen" and two Crossley Pielstick ranges with power outputs in the range 1.2MW to 15MW.-Bergen Range:...

 (formerly Bergen Diesel), Pielstick

SEMT Pielstick

SEMT Pielstick is a French diesel engine manufacturer based in Villepinte, France and owned by MAN Diesel, a subsidiary of MAN AGSEMT Pielstick was formed in 1988 when the business was acquired from GEC Alsthom by MAN and MTU, originally as a 50/50 partnership...

 and Wärtsilä

Wärtsilä

Wärtsilä is a Finnish corporation which manufactures and services power sources and other equipment in the marine and energy markets. The core products of Wärtsilä include large combustion engines...

 (formerly Wichmann) have made this type of engine.

Straight-nine engines in current production include models in the Rolls-Royce Bergen B, C and K series, and the Wärtsilä RT-flex60C-B, RT-flex82C, RTA84T-D, RTA84C, RTA96C, 20, 26, 32, Wasa32LN, 38, 46 and 46F series. The nine cylinder versions of these engines develop power outputs

Power (physics)

In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...

from 1620 kW to 51480 kW.