ENHANCED SHAFT ALIGNMENT IS MEANING:
This notation is assigned to shuttle tankers designed, constructed, and operated according to the shaft alignment procedures in ABS Guide for Enhanced Shaft Alignment.
The Guide’s intention is to address shafting arrangements, such as installations with no forward stern tube bearing, that may particularly benefit from a more detailed analysis and a more accurate and structured procedure to optimize the shaft alignment and improve the service life of the vessel’s powertrain.
Assignment of the ESA notation requires the review of plans and calculations by an ABS Engineering Office in accordance with the ABS Guide for Enhanced Shaft Alignment.
Assignment of the ESA+ notation requires the review of plans and calculations by an ABS Engineering Office and compliance with the installation, measurements, and sea trial requirements, following the ABS Guide for
Enhanced Shaft Alignment. In addition, the ESA+ notation requires the attendance of an ABS Surveyor during shaft alignment efforts, which are in addition to regular Rule requirements, as explained in the Guide