Beloved by many seafarers and shipowners past and present as an intrinsically reliable, smooth-running, and powerful means of propulsion, the steam turbine is finally falling out of grace with the shipping industry. The demise of steam main machinery is being hastened by increasing environmental scrutiny and difficult market conditions within its particular sphere of influence.

The steam turbine is a device for obtaining mechanical work from the energy stored in steam and was long the first choice for very large power main propulsion units. Over recent decades, the LNG carrier segment has become the last bastion of the steam turbine in commercial shipping.

Continuity of the steam turbine through a period of rapid advance in marine engineering technology has been abetted, until comparatively recently, by some major operators of LNG carriers undertaking fleet investments that endorse the design improvements achieved by Japanese makers championing the reheat principle.