Propeller viewing trials are a necessary adjunct to towing tank and cavitation tunnel tests, if a full assessment of propeller performance is to be made. Unfortunately, viewing trials are rare because of the expense and disruption caused by the installation of propeller viewing ports. Additionally, assessment of cavitation inception and other performance parameters is difficult because of the poor performance of the human eye under stroboscopic lighting.

The Defence Research Establishment Atlantic, in conjunction with its contractors, Networx Technologies and Eyretechnics Limited, has developed video systems to overcome many of the deficiencies of conventional viewing trials. The development of this system is described, from a concept demonstrator employing conventional viewing ports, to systems which are external to the hull. The external systems eliminate the need for viewing ports and can be installed by divers with the ship afloat. The current system, cperating with shaft synchronized stroboscopic lights, allows storage of selected propeller cavitation images for simultaneous or later display on conventional video equipment. Examples of installation and trial results are given.

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