Feb 122013

crankHolding on to something that revolves at high speed is not conducive to a long life but inattention and a lack of safety instincts can result in the sorts of  incidents covered in Denmark’s Maritime Accident Investigation report on a fatality aboard the Nicolai Maersk on 26 April 2012.

Nicolai Maersk arrived at Jebel Ali, Dubai, United Arab Emirates. Shortly after arrival at 1515 hours the ship began loading and unloading containers.

During the stay in Jebel Ali, the ship was to receive lubricating oil both in bulk and in drums. The drums were to be hoisted on board by means of the aft stores crane. The lubricating oil in bulk was to arrive by truck and be pumped on board at the bunker station on the upper deck close to the gangway.

In order to receive the oil, preparations were made to hoist on board the bunkering hose for lubri-cating oil. The intention was to use the fuel oil hose and Suez boat handling davit for hoisting the hose for the lubricating oil. While preparing the crane, the 2nd engineer for some reason mounted the emergency operation crank fitted on a shaft that is directly connected to the electric motor powering the crane.

When mounting the emergency operation crank, he activated the lowering function on the remote control switch box whereby the crank started rotating at very high revolutions. The crank was hurled off and hit the engineer causing fatal injuries.

The report’s analysis says: “At the time of the accident, the electrical power to the crane was switched on in the air-conditioning
room and the ON/OFF switch on the control box was set to ON. The automatic mechanical safe brake was engaged. It was possible to lower the hook by means of the control box as the automatic mechanical safe brake declutches when the hoisting and lowering buttons are activated. An attempt to lower the hook by means of the emergency crank was impossible when the automatic brake was engaged. At the time of the accident, the brake was engaged.

Shortly before the accident, the 2nd engineer was seen with the control box in one hand and the crank for emergency operation of the crane in the other. Based on these facts, the 2nd engineer must have mounted the crank on the rotor shaft and thereafter activated the lowering button on the control box.

There are no indications that the 2nd engineer had been given instructions in operating the fuel oil hose handling and Suez boat crane except what was contained in the familiarization 24 hours of signing on. One of the items in this familiarization was an explanation of the use of the emergency stop. This familiarization can not oppose the elements of danger relating to the operation of the crane. Combined with the mounting of the crank without loosening the automatic brake first, indicates limited knowledge in the operation of this crane.

When the emergency crank is mounted and the lowering function on the control box is activated, the crank will instantly start rotating at a speed of 1,770 revolutions per minute. The crank handle will then move at a speed of approximately 186 km/hour based on a radius of 28 cm from the crank shaft to the handle. The crank has a weight of 3.2 kg. As the crank does not fit tight on the shaft end, but is able to wriggle, it could be hurled off within a very short moment after activating the
lowering function, thus hitting and causing fatal injury to the 2nd engineer.

After the accident, it was found that the hook was lowered approximately 10 centimetres. This shows that the crane had been activated for lowering for less than half a second, during which time the crank had rotated about 15 times.

The interlock limit switch that should have cut off the power to the crane in case the emergency operation crank was mounted on the crane was mentioned both in the crane specifications and in the ship’s deck operation manual. However, the absence of this safety feature was not acknowledged by the manufacturer, the classification society or during regular external and internal inspec-
tions and maintenance. The absence of the interlock safety switch was thus never recognized and this latent risk became active when the emergency crank was used in an uncommon way by a crew member with limited experience and knowledge in operation the fuel oil hose handling and Suez boat crane.

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