scope:

Introduction

ESA or ESA+ Notation

Requirements of this Guide are optional for classification purposes. However, where assignment of the optional notation ESA - Enhanced Shaft Alignment or ESA+ is requested, provisions of this Guide are compulsory.

This Guide provides criteria for additional calculation requirements, such as design optimization, as well as more detailed requirements regarding the shaft alignment procedures in support of the optional Notations. Typical differences can be explained through the flowchart examples in 1/1.1 FIGURE 1.

Objective

The objective of this Guide is to identify additional requirements and procedures beyond the minimum requirements currently specified in the ABS Rules for Building and Classing Marine Vessels so as to further enhance the shaft alignment to make it more robust and less susceptible to unaccounted disturbances or errors in production. Vessels designed, constructed and operated in compliance with the requirements of this Guide may be assigned the Class Notation ESA or ESA +.

General Requirements

The shaft alignment procedure for vessels with the ESA+ notation requires that the final shaft alignment sighting be carried out after the vessel stern blocks are fully welded and all of the heavy stern structure is in place, such as any stern accommodation block, including the main engine and/or gearbox. This is to be verified by the attending Surveyor.