Water ingress to bow thruster space
- Safety Flash
- Published on 28 July 2010
- Generated on 17 June 2026
- IMCA SF 05/10
- 3 minute read
A Member has reported an incident in which flooding occurred in the bow thruster space of a vessel, resulting in damage to the bow thruster.
What happened?
The vessel’s crew were emptying a fresh water tank using the bow thruster room direct bilge eductor system via the fire main. The bilge alarm was activated, acknowledged and accepted by the duty engineer who was about to complete his watch and was preparing for the handover. The status of the bilge alarm was verbally passed to the next duty engineer, but owing to distraction the engineer forgot about the alarm and the bilges were allowed to fill up. The flooding was discovered after 36 hours when the water reached the floor plate level. As a result of the flooding, parts essential to the bow thruster were damaged beyond repair and scheduled sea trials had to be postponed.
The impact of this incident was significant in terms of breaching basic watch-keeping ‘routine’s and damage to equipment. Our member’s subsequent investigation identified a number of key issues and lessons learnt.
Key Issues
- Failure of basic watch-keeping practices.
- Lack of understanding of Chief Engineer’s Standing Orders.
- Lack of ‘routine’ inspection and cleaning of bilge suction valves and filters.
- Absence of an approved bilge system drawing.
- System integrity not inspected prior to use and followed up during operation.
Lessons Learnt
- Chief Engineer’s Standing Orders should contain clear instructions regarding watch-keeping ‘routine’s, especially with reference to acknowledgement of alarms and subsequent actions by the duty engineer.
- All alarms should be investigated immediately and acted on accordingly by the duty engineer. Bilge high levels should not be left in the alarm condition. These must be investigated and pumped out completely and the cause verified and rectified.
- A complete set of instructions for the use of the bilge system should be available to watch-keepers and engine room staff.
- Watch-keepers and engine room staff should be familiar with the operation of the bilge system.
- Bilge suction filters and the condition of screw down non-return (SDNR ) valves should be checked at regular intervals to make sure there is no debris between the seating faces.
- Bilge system drawings should be verified against the existing system, and if any amendments are necessary these should be made by the company drawing office approved by the Classification Society.
- Bilge system drawings should be included in vessel familiarisation for joining engineering staff.
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.
The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.
All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.
IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.
The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.
Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.