scope:

This NES defines and establishes the accuracy requirements and structural tolerances to be employed by the Shipbuilder to ensure that the structure of surface vessels is built to the required dimensions. It is applicable to the structure of RN surface ships constructed of steel and/or aluminium

The tolerances covered range from those applied to component parts and sub-assemblies through to the principal dimensions of the assembled structure.

Typical illustrations are included to convey the permissible variations on dimensions, distortions or misalignments relative to Datum points. 

Accuracy requirements are also included for: 

the installations of seatings for machinery and weapons and;

the control of major overhanging structure and shaft alignment. 

Composite vessels such as GRP and wood are specifically excluded from this NES.