Man Overboard!
With huge waves and strong winds ever present, ship
personnel do sometimes get swept overboard. What are the steps to be taken
during those times?
It should be considered an emergency, because any person
falling into icy winter waters is likely to suffer from
hypothermia. His body
heat will very quickly be taken up by the water that will soak through his
clothing.
Hopefully, somebody from the ship knows that there is a man
overboard, otherwise the chances of survival in the wide ocean is almost nil.
The first thing to do is to throw a lifebuoy to the man in
the water. This will at least keep him afloat until the rescue operation can
take place. Drowning can be avoided if the person can keep afloat.
Because the ship is so huge and heavy, it is not possible to
stop it immediately. The momentum of the ship will cause it to travel quite a
far distance before it can be brought to a complete stop. The rotating propeller
blades also can become very dangerous to any floating object on the water due to
its churning and cutting actions, so reversing is out of the question.
The turning circle of a ship is also very large. The turning
of a ship depends on the water flow through the rudder plate at the stern of a
ship. This effect depends a lot on the speed of the ship. If a ship were to
stop, its rudder becomes almost useless for turning. (That's why we need
tugboats when maneuvering in port)
The ship's officers are trained to immediately initiate
rescue operations. They will not stop immediately because this will not help.
There are 2 common methods for bringing the ship back to the
location of the man overboard:
- The Elliptical Turn
- The Williamson Turn
The
Elliptical TurnThe rudder is put hard over towards the side on which the man
fell and held hard over until the vessel has turned through 180 degrees. The
ship is then steadied until full speed is regained and then the rudder put hard
over once more.
In calm conditions, the vessel should regain her original track, but this may be
affected by wind and sea conditions.
The animation below shows the Elliptical Turn.
The Williamson Turn
Williamson Turn was developed to return to a certain starting position more quickly.
The ship is put hard over towards the man and held hard over. When the ship is
heading about 60 degrees from her original course, the wheel is put hard over in
the opposite direction until the ship is on a course reciprocal to the first
course.
Steadying up on this course should bring the vessel back to the man in
the water. This maneuver depends on the value of the angle through which the
ship's head swings before the helm is reversed.
This value is dependent on the
ship, direction of turn, loading condition and depth of water. This need to be
determined by trial maneuvers. The skill of the navigating officer doing this
maneuver will determine how accurately the ship is brought towards the man
overboard.
Down in the engine room, the engineer officers will be
standing by to maneuver for speed and astern braking operations, especially when
approaching the man overboard.
When the ship approaches the man floating on the water it is
very important not to cause unnecessary wave movement, and not to let the
propeller rotation cause him injury.
Deckhands will be standing by on lowered gangways with ropes
to assist in the rescue operations.
The rescue operations will be made more difficult in rough
weather, poor visibility and low light conditions.
Depending on how cold the water, most probably the victim
will have to be treated for hypothermia.
More about Rough Seas.
Hurricanes and Typhoons. |
