ISO/TC 8/SC 8/WG 14 - Propulsion system

This document specifies a full-scale test method for propeller cavitation observation and hull pressure measurement. The objective of the test is to investigate the propeller cavitation behaviour and its effects on the hull vibration problems. The test method comprises the specification of the test instrumentation and implementation, construction requirements to ensure structural safety, test and measurement procedures, and reporting documentation. This document is applicable to ships in the following stages: — before or during sea-trial, prior to delivery stage (vessels under constructions), and — after delivery stage.

This document specifies a model test method for propeller cavitation noise evaluation in ship design, focusing mainly on the noise source localization. The procedure comprises the model test set-up, noise measurements, data processing and source localization. The target noise source being propeller cavitation, this document describes the test set-up and conditions to reproduce the cavitation patterns of the ship, which is the same as in ISO 20233‑1. The noise measurements are performed using a hydrophone array for the source localizations. Therefore, the instrumentation of the hydrophone array is also addressed, as well as a suitable array signal processing of the measured data. Finally, a method to visualize and to interpret the results is presented.

ISO 20233-1:2018 specifies a model test method for propeller cavitation noise evaluation in ship design. The procedure comprises reproduction of noise source, noise measurements, post processing and scaling. The target noise source is propeller cavitation. Thus, this document describes the test set-up and conditions to reproduce the cavitation patterns of the ship based on the similarity laws between the model and the ship. The propeller noise is measured at three stages. The measurement targets for each stage are propeller cavitation noise, background noise, and transmission loss. For the source level evaluations, corrections for the background noise and the transmission loss are applied to the measured propeller cavitation noise. Finally, the full-scale source levels are estimated from the model scale results using a scaling law.