Editing Steam engine (section)

=== Marine engines ===

[[File:Triple expansion marine steam engine.jpg|thumb|right|A triple-expansion [[marine steam engine]] on the 1907 oceangoing tug [[Hercules (1907)|''Hercules'']]]]

{{Main|Marine steam engine}}

Near the end of the 19th century, compound engines came into widespread use. [[Compound steam engine|Compound engines]] exhausted steam into successively larger cylinders to accommodate the higher volumes at reduced pressures, giving improved efficiency. These stages were called expansions, with double- and triple-expansion engines being common, especially in shipping where efficiency was important to reduce the weight of coal carried.{{sfn|Hunter|1985|p=}} Steam engines remained the dominant source of power until the early 20th century, when advances in the design of the [[steam turbine]], [[electric motor]]s, and [[internal combustion engine]]s gradually resulted in the replacement of reciprocating (piston) steam engines, with merchant shipping relying increasingly upon [[diesel engine]]s, and warships on the steam turbine.{{sfn|Hunter|1985|p=}}<ref Name="Wiser"/>