PropellerSeismo - Ship propeller condition monitoring using seismic measurements

Motivation

A good propeller condition is important for its efficiency and therefore the performance and low emissions of a ship. During ship operation, grounding, collision with anchor chains or bio-fouling can cause the condition to deteriorate. It is therefore important to monitor the condition of the propeller during ship operation. This is currently done between dry dockings through inspections carried out by divers or ROVs (remotely operated vehicles). There are also sensors on board ships that measure shaft vibrations, for example, in order to detect imbalances. At present, however, it is not possible to make statements about the propeller on land. 

As part of the project, the possibility of using seismic measuring devices to monitor propellers is to be investigated. The advantage over established methods is the easy accessibility of measurement results using shore-based sensors. Compared to hydroacoustic measurements, the sensitivity at low frequencies is particularly interesting.

Seismic measurements

Geophones are seismic measuring devices that record the oscillationt of the earth's surface. Traditionally, seismic measurements are used for geophysical problems such as earthquakes, landslides or volcanism. In principle, however, all seismic waves can be recorded, regardless of the origin. In recent years, new areas of application such as sediment transport in rivers or glacier activity have been developed.

Research project

As part of the PropellerSeismo project, geophones are used to record seismic signatures of passing propellers. Systematic modelling tests will be used to show the extent to which it is possible to draw conclusions about the condition of the propeller based on the signatures. The aim of the project is to assess the condition of the propeller based on its seismic signal. In this way, shore-based monitoring can be carried out in channels, for example, which can help to recognise poor propulsion efficiency at an early stage. This means that dry dock inspections could be scheduled as required rather than at fixed intervals.