In 1997, major concerns on thruster reliability expressed by IMCA members prompted the production of two reports - IMCA M 129 and IMCA M 137. Since then, there have been a number of developments, which prompted the Marine Divison Management Committee to commission updated guidance.

In addition to reviewing the earlier reports (and revising IMCA M 137), this new report has been commissioned, intended as a sister volume to IMCA M 129 - "Failure Modes of CPP Thrusters". That document describes in detail the failure modes of thrusters and common faults that have been experienced in service. The industry has since moved towards utilising fixed pitch thrusters and, more recently, podded propulsion units. This document is intended to fill that gap. In order to avoid repetition, it does not discuss thruster components which have been extensively dealt with in the earlier document, but for completeness the failure modes of fixed pitch thrusters have been considered in the failure table section.

Related publications:

• Failure modes of CPP thrusters
• General thruster specification and bid information questionnaire