In the latest UK MAIB Safety Digest, a case that involved a training vessel comes to highlight that lifejackets save lives and that cold water shock can cause physical reactions that increase the risk of drowning.
It was a warm sunny day and an anchored training ship had just recovered its sea boat after an exercise. While cleaning the sea boat the coxswain dropped a small engine part into the water and it began to float away. Without thinking, the officer on the ship’s deck removed their lifejacket and jumped overboard to recover the engine part.
The officer managed to swim to the floating engine part and retrieve it, but realised they were unable to swim against the current and that they had started to drift away from the vessel.
Once the coxswain realised what had happened they immediately called the chief officer (C/O) to the deck and awaited orders. The speed of current was 1.3kts, meaning that the officer was being pushed 30m away from the ship every minute they were in the water.
As well as fighting against the current, the officer was also experiencing the difficulty of swimming while fully clothed in water temperatures around 15°C. As the officer struggled on, they slowly lost their ability to swim and suddenly realised the danger they were in with no lifejacket to keep them afloat.
The C/O decided the best course of action was to relaunch the sea boat and send a crew member to recover the officer. The sea boat was deemed the fastest method of recovery and quickly reached the officer, who managed to climb into the boat unaided. The officer was medically assessed once back on board the training ship and was closely monitored for the next few hours despite no signs of injury.
Lessons Learned
#1 Equipment
Lifejackets save lives. The officer in this case decided to remove their lifejacket before jumping into the water because they thought the automatic inflation of the lifejacket would impede the retrieval of the engine part. Fortunately, the officer was unharmed, but the consequences of being in the water without a means of flotation could have been far more serious.
#2 Cold water shock
The effects of cold water shock on the body can result in drowning. The officer survived the initial immersion, but the water temperature quickly affected their ability to swim as their muscles began to weaken. At 15°C the water temperature was within the bounds of cold water shock and had started to cause cold water incapacitation and swim failure. Remember: water temperatures in UK summer months can be low enough to pose risk (see figure).
#3 Plan
Take a moment to think. The officer reacted instinctively and with more concern for the engine part than their own safety. Discussion between the officer and the coxswain would have resulted in an agreed safer course of action to retrieve the part and avoid danger.
