Fire-fighting water jet hits antenna – Failure of limits, stops and safeties

A member has reported an incident in which the water jet from a fire-fighting monitor hit an MF/HF whip antenna and damaged it. The incident happened during monthly testing of fire-fighting equipment. It was discovered that the horizontal travel of the fire-fighting monitor went beyond acceptable limits, allowing the water throw to hit and damage a nearby whip antenna. The testing was immediately stopped and damage was assessed.

Our members’ investigation revealed the following:

• Maintenance on this fire-fighting monitor had been carried out earlier by third party contractors;
• The root cause was determined to be incorrect adjustment of turning limit switch of the fire-fighting monitor;
• It was noted that it was important to regularly check the turning and elevation limit switches settings of fire-fighting monitors.

Our member took the following corrective actions:

• The limiting for the monitor was adjusted so that its throw remained in a safe sector of operation with no ship’s equipment or structure in line with the water throw;
• On completion of major maintenance on machinery/equipment, full trial runs and acceptance tests should be conducted to ensure satisfactory operations;
• Machinery and equipment not used regularly during normal operation of the vessel – such as fire-fighting monitors and pumps – should be tested at regular intervals in accordance with the vessel’s planned maintenance schedule. Before such tests it should be confirmed that all safety settings and limits installed in the system are functioning correctly;
• Our member reiterated the importance of stopping the job if work is being done in an unsafe manner.

Members may be aware of an unfortunate incident which occurred on an offshore support vessel (OSV) during September 2016, also during testing of a water cannon, in which one crewman died and three were injured.

Members may wish to refer to the following incidents (search phrase: limit switch):

• Fatal accident with lifting appliance
• Damage to crane winch