Reciprocating Engine Era

The reciprocating engine era covers the late nineteenth and early twentieth centuries when piston steam engines, especially the triple-expansion type, dominated merchant propulsion. A triple-expansion engine takes steam through high-, intermediate-, and low-pressure cylinders in turn, extracting more work per pound of steam than a simple or compound engine; higher boiler pressures and the surface condenser made it efficient enough to displace sail on most routes by the 1880s and 1890s. Steam turbines and then diesels later superseded the reciprocating plant on fast and large ships.