Avoiding “Death Traps on Ships” – Understanding Dangers of Mooring Operation

A cargo vessel’s main earning potential is not tested from the amount of time it travels at the sea but from the efficiency of its operation at ports where the cargo is handled.


An efficient port and cargo operation of a ship is what every ship operator expects from its deck crew. The first and foremost operation performed by the deck crew as the ship reaches the port – the mooring operation, is also one of the most difficult and dangerous jobs on ships.


What makes Mooring Operation dangerous?

There have been several cases reported in the past about accidents during mooring operation that has led to severe damage or deaths of seafarer.

The mooring area on a ship comprises of foreword and aft parts of a vessel where winches are installed to pull the ropes from tug and jetty bollards.

The Mooring area is equipped with several equipment and systems such as winches, hydraulic motors, bollards, piping valves, anchor chain etc.

Following factors make this mooring area and operation dangerous:

  • Use of old and damaged wires and ropes
  • Unclear mooring area with unused ropes and equipment
  • Mooring ropes are not fastened but stored at winch drum end
  • Undersized and untrained operating staff
  • Supervisor of operation is involved with some other work as a result of less crew members
  • The painting of mooring area is badly planned with all surfaces and equipment painted with same colour not highlighting hazardous and tripping sights
  • Over painting of drum including corners causing rope damage
  • No warning marks painted
  • Non slip deck is not available
  • Crew not aware of Snap Back Zone
  • Crew not aware of dangers of rope bight
  • Rope and metal line are joined directly without using thimble which may lead to parting of rope
  • Inspection and tests of mooring machineries and ropes are not carried regularly
  • Ropes are not arranged on split type drum correctly. The smaller drum must have 4-5 turns and rest of it should be on larger drum

All the above points are considered by the supervisor i.e. Chief officer or 2nd officer while preparing a mooring operation beforehand.

From the above listed points, two important and dangerous phenomena which are responsible for maximum causalities in mooring of a ship and which are also considered as death traps are-

1)      Snap Back Zone:

The highest number of injuries and deaths during a mooring operation on a ship are due to parting of the rope or wire hitting back to a crew member standing in the area of the rope. The area traveled by the parted rope having a force enough to kill a person on its way is known as snap back zone.

When ropes are pulled straight then the snap back zone is minimal but if the ropes are turned in bollard or roller then the snap back area increase. This is shown in the diagram below:

Ship has to be pulled by tugs or by ships own winches for making it close to the jetty for berthing. This requires strong ropes and wire to be stretched in tension for pulling the ship. Every rope and wire has got its own endurance limit above which it will fail and part off. The endurance limit will get reduce if the rope is old or not maintained properly.

The rope will break or part when it is in tension due to pulling action and when these parted rope swings back in its snap back zone and hits a person standing there, it can be a deadly blow.


The snap back zones in forward part of the ship undergoing mooring operation increases well in number due to several restrains and turn points with lines in tension as shown in the diagram

The crew performing the operation must be thoroughly trained and qualified with the snap back zone. The ship fore and aft parts must highlight the snap back zone with signalling paints so that the crew will be aware not to be on that painted mark when the ropes are under tension.


2)      Rope Bight:

Mooring ropes are long and heavy ropes stored on board ships in coil form. When these ropes are under operation, they tend to form a coil or ring shape naturally known as rope bight.


If a person involved in mooring operation comes under this rope bight, the pull of the rope can drag him over the ship or smash him in the hard deck over machines. Several injuries and deaths have been reported due to crew unaware of standing over bight and dragged by the rope.

The best ways to avoid accidents due to rope bight are:

  • Crew must be aware of where he is standing while handling the ropes or when near them.
  • Supervisor must concentrate on others action and should not involve himself/herself in the operation as working hand.
  • Inexperienced crew such as cadets and fresh ratings should bellowed to handle rope only under supervision
  • Only required crew should be present on mooring station. It has been commonly seen that those people who are not involved in the operation (Engine crew or off timers coming on deck) visit the mooring operation area. Thus, notice should be placed for restricted entry.
  • Enough number of deck hands to be present on mooring station to perform the operation smoothly.

                                                Remember, Bights don’t always look like bights.

Safety of human life on ship must be the first priority of all operations performed.

Life is precious, always think about Safety First.

Image Credits: thechalkfaceclassictugsgeneralcargoship

Article Credits: Marine Insight

Note: The Intention of this article is not to threaten seafarers but to warn them about the dangers of mooring operation on ships and educate them on the procedure to carry it out safety.

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