Secondary Bilge Alarm on…

Secondary Bilge Alarm on…

Secondary Bilge Alarm on…

My 15 metre trawler was at sea when a 2″ sea water discharge pipe failed behind the A60 engine-room lagging. Water ran un-noticed behind the insulation into the bilge and was rapidly flooding the engine room.
Unknown to us the main bilge alarm panel had been disabled by a short circuit in the fish room system, but fortunately a totally separate permanently wired secondary system activated (for the first time in six years!!) alerting us and we were able to identify the source of the leak and pump out without problem.

And Bilge Alarm Off

My 30m beam trawler came off the slip following a bottom paint and minor refit.  An incomplete job trickled away over the weekend and by Monday morning the engine room had two metres of water in the bilge, causing considerable water damage.

The main battery supply was switched off and no alarms were active.  A permanently live alarm with a strobe flasher in the wheelhouse would have almost certainly alerted someone on the quay.

The following is an extract from the applicable Regulations; “The Code of Safe Working Practice for the Construction and Use of 15 metre Length Overall to less than 24 metre Registered Length Fishing Vessels”:


4.3.3    Bilge Alarms    A bilge alarm sensor should be fitted in the propulsion machinery space and fish hold(s) of the vessel.  These alarms should be accessible for regular testing.

Existing vessels should be fitted with a fish hold sensor by the first periodical survey under this Code.    To prevent pollution, bilge sensors in compartments containing pollutants should not automatically start bilge pumps.    Any auto-start bilge pump serving a clean compartment should be fitted with an audible and visual alarm at the control position(s) so that the reason for pumping may be investigated. Such pumps should also be fitted with a “manual override” to start the pump.    Each dry compartment provided with a bilge suction capability (built-in or portable) should be fitted with a bilge level alarm if the level of bilge water can not be readily checked visually without entering the compartment. Alternatively, spring loaded drain valves may be fitted outside the compartment as a means of checking the bilge level.    A bilge alarm should provide an audible and visual warning at the control position(s).    Each engine room bilge alarm system should be provided with:

  1. i) a secondary, independent bilge alarm system; or
  2. ii) a “fail safe ” warning should the bilge alarm circuit become faulty.

Existing vessels should be fitted with (i) or (ii) above, by the first periodical survey under this Code. Further guidance for bilge alarms and bilge pumps is provided in MGN 165(F).


The Maritime Advisory Board makes the following observations:

  • Vessels that are left temporarily unattended for anything other than a relatively short period, whether for repair or other reasons, should be secured e.g. sea cocks closed, etc.
  • When fitting a secondary alarm consideration should be given to ensuring that it remains live when the vessel’s main power plant is shut down and that an alarm condition is visible externally.
  • Whatever the alarm system fitted ensure it is tested regularly.