Low speed two-stroke engine designers have invested heavily to maintain
their dominance of the mainstream deepsea propulsion sector formed
by tankers, bulk carriers and containerships. The long-established
supremacy reflects the perceived overall operational economy, simplicity
and reliability of single, direct-coupled crosshead engine plants. Other
factors are the continual evolution of engine programmes by the
designer/licensors in response to or anticipation of changing market
requirements, and the extensive network of enginebuilding licensees
in key shipbuilding regions. Many of the standard ship designs of the
leading yards, particularly in Asia, are based on low speed engines.