Standards Development

Scope

This document applies to model tests of thrust and manoeuvring force and moment for waterjet units. It defines terms and quantities for force characteristic tests for waterjet unit and specifies requirements for test conditions, devices and methods and analysis procedure.

This document does not include hydraulic system and control system of waterjet units. This document does not provide manufacturing tolerances in contract.

Purpose

Rapidity and manoeuvrability are important performance of ships. In recent years, ship-owners pay more and more attention on ship manoeuvrability. Waterjet propulsion is one of the mainstream propulsion modes of high performance ships. For ships using waterjet propulsion, rapidity is directly related to the thrust of waterjet unit and manoeuvrability (turning and astern) is directly related to the manoeuvring force (steering force and reversing force). Thrust and manoeuvring force contribute to the force characteristic of waterjet units. At present, the thrust and manoeuvring force provided by waterjet propulsion manufacturers are usually estimated based waterjet propulsion pump hydraulic performance. Based on waterjet propulsion theory related numerical calculation and model test research, different scholars and manufacturers build different estimation methods, of which the accuracy is closely related to parameter values and is difficult to judge. Therefore, it is necessary to build unified and normative force characteristic test methods to measure the force characteristic of waterjet units. In addition, terms and symbols, test requirements and analysis procedure are also specified to judge and compare methods from different parties on the same basis. This document will provide acceptance criteria for designers and users of waterjet units.