February 1997 Failure of non return valves causes capsize
Seafarers are warned to pay attention to non return valves following the sudden capsize of a fishing trawler and drowning of a deck hand.
Information on non return valve malfunction
Maritime New Zealand’s investigation report states that the capsize was caused by a loss of stability due to back-flooding of the fish hold via the vessel’s bilge pumping system. The flooding of the fish hold was caused by the malfunction of three non return valves in the bilge pumping system. Although a policy relating to the need for non return valves to be closed when not in operation was communicated to all skippers by company management, this policy was not adhered to on this occasion.
Safe practice tips
The report recommends, among other things, that:
- Personnel who operate non return valves in the engine room should be aware that these valves can be prone to malfunction.
- The maintenance staff ashore and afloat carry out regular checks and maintenance on non return valves.
- Skippers and engineers note the dangers of free surface effect.
Original source content - Boat Notice 051997, February: Failure of non return valves causes capsize.