This document summarizes an incident where a fast rescue craft experienced an unplanned descent from 23 meters above sea level while being retrieved. The descent continued even when controls were returned to neutral and the emergency stop was activated. An investigation found that both hoist brakes had functionally failed, likely due to the installation of an incorrect hydraulic valve. Four people were aboard but no injuries occurred. Key learnings included ensuring replacement parts are identical, understanding potential failure modes, following maintenance procedures, and ensuring third party maintenance tasks meet company standards.

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Marine Safety Forum – Safety Flash 13-29
Issued: 1st
July 2013
Subject: Fast rescue craft unplanned descent
An FPSO’s fast rescue craft (FRC) was retrieved to a height of 23 metres above sea level following
operational duties. When “hoist up” control input was given via the davit controls the FRC
commenced an unplanned but gradual descent to the sea. With controls returned to the neutral
position the descent continued. Activation of the emergency stop also did not stop the descent.
It was concluded that both hoist brakes had functionally failed and that the only brake arresting the
descent was the mechanical centrifugal/inertia brake. Four persons were aboard the FRC but no
injuries were sustained.
Critical Factors
1. Installation of incorrect hydraulic valve causing pressure lock in hydraulic system (valves
nearly identical in appearance but part numbers differed by one character).
2. Deficiencies in third party testing/certification procedures.
3. Operator maintenance procedures not fully followed by contractor.
Learning’s
 Ensure replacement parts are ‘like for like’.
 System failure modes must be fully understood and clear mitigative maintenance check
implemented to address those failure modes.
 Compliance to maintenance procedures, in particular technical integrity maintenance, is
critical.
 Ensure a full understanding of the maintenance and assurance tasks that are completed by
third parties and that these tasks are clearly defined, documented, and in compliance with
your company requirements.