Institute of Marine Engineering, Science & Technology - IMarEST
Webinarium, 07.04.2021r. online

Marek Narewski
Polski Rejestr Statków S.A., Gdańsk

Alternative class survey methods

Among the PRS Rules, one can find Publication 2 / P - Alternative Machine Equipment Supervision Systems, which contains requirements for machine equipment monitoring (CM - Condition Monitoring system) and supervision of machine equipment maintenance based on condition based maintenance (CBM). . The CM / CBM system is an alternative PRS supervision system over the ship's machinery, based on the approved and implemented Condition Monitoring Program (PMS). This system enables the shipowner to collect data and analyze the technical condition of the machinery equipment included in it on an ongoing basis and to define the individual scope and dates of repairs for them, or their open inspections.

The main factor determining the taking of preventive or corrective actions are decisions resulting from the analyzed trends of measured values based on manufacturers' guidelines or indicators specified in recognized CM / CBM standards, which indicate signs of a decline in performance or an impending failure. In particular, the application of CM / CBM may apply to the following devices:


    electric rotating machines,


    reduction gears,



    and other equipment, the acceptance of which for CM / CBM survey is each time considered by PRS.

In this CM / CBM system, various methods of monitoring the condition of devices are used, and the data for the development of decisions is obtained using the following measurement and inspection methods:

    Measurement and analysis of ship structure vibrations

    acoustic diagnostics,

    thermal imaging diagnostics a,

    sampling and oil analysis,

    measurement and analysis of mechanical vibrations.

Due to the growing scope of automation of marine machinery for servicing, which requires specialist knowledge and the tendency to reduce the number of engineers, PRS meets the needs of performing the necessary technical inspections in the most optimized way for the ship owner. Maintaining the technical condition of machinery and thus ensuring safety is the overriding goal of the Polish Register of Shipping. PRS develops the Rules and Methods for Conducting Technical Surveys with the use of alternative methods on ships in operation and the implementation of this type of classification supervision for each newly built vessel.