crosshead engine

Some crosshead engines had more than one cylinder, in which case the piston rods were usually all connected to the same crosshead.

Slow-speed engines are predominantly large two-stroke crosshead engines, hence very different from high- and medium-speed engines.

Most modern larger merchant ships use either slow speed, two stroke, crosshead engines, or medium speed, four stroke, trunk engines.

The crosshead engine, also known as a square, sawmill or A-frame engine, was a type of paddlewheel engine used in the United States.

As marine engines grew steadily larger and heavier through the course of the century, the high center of gravity of square crosshead engines became increasingly impractical, leading to their abandonment by the 1840s in favor of the walking beam engine.

The crosshead engine is described as having a vertical cylinder above the crankshaft, with the piston rod secured to a horizontal crosshead, from each end of which, on opposite sides of the cylinder, extended a connecting rod which rotated its own separate crankshaft.