Classification society Bureau Veritas has introduced a new set of requirements for shaft alignment on high powered ships. The ESA notation will help ensure the integrity of the structure and shaft bearings on very large vessels such as ultra-large container ships and the next generation of very large LNG carriers. Jean-Francois Segretain, deputy technical director, Bureau Veritas, said, “As ships grow in size and we seek more fuel economies we are now seeing vessels with shafts handling over 20MW of power driving large diameter propellers of over 30 tons weight. Critical attention has to be paid at the design stage to analyzing the elastic shaft alignment and ensuring that the bearings and structure match the shaft response, especially when the vessel is turning.