INTERTANKO/OCIMF Safety Bulletin - Anchor Windlass Safety Advice
OCIMF and INTERTANKO have been made aware that some anchor windlass machinery in service may still be subject to catastrophic failures similar to that experienced in an incident investigated eight years ago by the UK Marine Accident Investigation Branch (MAIB). The MAIB's "Report on the investigation of the catastrophic failure of a windlass hydraulic motor on board Stellar Voyager" can be foundhere
. One person was injured in that incident. The report concluded that the most likely cause of the catastrophic failure was over-pressurisation of the system due to the reversal of the hydraulic motor as the chain rendered.
Following the incident, recommendations were made to several stakeholders. Despite these recommendations, and although rare, it has recently come to the attention of OCIMF and INTERTANKO that similar incidents have since occurred. The most recent incident in March 2017 resulted in a serious injury.
Members can help to reduce the number of incidents by doing the following:
- Understand the design/operating limitations of windlasses fitted. Limiting factors to consider may include current, wind, water depth, and the length/weight of the chain and anchor.
- Be familiar with all manufacturer equipment and operation manuals.
- Be guided by recommendations in the OCIMF publication Anchoring Systems and Procedures, especially section 220.127.116.11 Protection Against Catastrophic Failure.
- Contact the manufacturer(s) of windlasses fitted for further clarification and understanding of design and operating limitations.
- Based on discussions with the windlass manufacturer the ship operator may wish to consider installing protective containment around the hydraulic motor.
- Take note of IACS UR A3 Anchor Windlass Design and Testing, section 3.4 that will be uniformly implemented by IACS from 1 July 2018
Although the MAIB report on the Stellar Voyager incident largely focused on a bent axis axial piston variable displacement pump, it is unclear to OCIMF and INTERTANKO how many windlasses remain in service and at risk of a similar failure. If Members are unsure, we urge them to contact their windlass manufacturer(s) and seek guidance on this important safety issue.