#2 Ship Manoeuvring - for rescue of person overboard
Ship Manoeuvres for a Man Overboard
The Round or Anderson Turn is a maneuver used to
bring a ship or boat back to a point it previously passed through, often for
the purpose of recovering a man overboard.
This turn is most appropriate when the point to be
reached remains clearly visible. Both will require more time before returning
to the point in question.
1. If the turn is in response to a man overboard,
stop the engines.
2. Put the rudder over full. If in response to a
man overboard, put the rudder toward the person (e.g., if the person
fell over the starboard side, put the rudder over full to starboard).
3. When clear of the person, go all ahead full,
still using full rudder.
4. After deviating from the original course by
about 240 degrees (about 2/3 of a complete circle), back the engines 2/3 or
full.
5. Stop the engines when the target point is 15
degrees off the bow. Ease the rudder and back the engines as required.
If dealing with a man overboard, always bring the
vessel upwind of the person. Stop the vessel in the water with the person well
forward of the propellers.
The Williamson Turn
John A. Williamson entered the US Navy as a seaman
and later became the Commanding Officer of the USS England. As an instructor
ashore, Williamson developed a series of turns used to bring a ship back on its
own wake after a man fell overboard. Williamson recommended they
teach the turn as a maneuver for man overboard recoveries during night and low
visibility conditions.
Williamson after retirement wrote, “I’ve gotten
letters and seen articles where people have been picked up using (the turn). I
don’t have a clue as to how many. I don’t know whether it’s ten or 5,000. I
don’t feel that there’s any glory to me though. It’s just something I came up
with that turned out to be worthwhile. I don’t think I’m due any glory for it,
or any fame or anything like that.”
The principle behind the “Williamson Turn” is to return a ship to the
exact location where a seaman fell overboard by using the ship’s wake as a
reference point. This requires that a ship first turn to starboard, followed by
a turn to port that is concluded when the ship crosses its own wake.
This is the most efficient of all the turns till
date.
The manoeuvre basically comprises of the following
helm movements:
A wheel over of hard over on any side suitable
To maintain the helm until the course has altered
by 60 degrees.
Once this is achieved the wheel is put hard over on
the opposite side
The wheel is kept at hard over until about 20
degrees remain to bring the vessel to the reverse of original course, when the
helm is put to amidships
Helm is used to ease the ship on to the reverse
course. (It helps if the original wake of the ship can be seen)
This is the most efficient since without any
navigational aid the ship would retrace her path and go up the course line.
Small deviations are to be allowed for the tide and
current and wind effects. But overall is the best method to recover or to at
least go over the path of the ship.
The above plot is an actual done on board a medium
sized tanker and as can be seen there is very small deviation. Of course the
positions were plotted by GPS fixes. But the position fixing was superfluous.
(MOB position: Lat. 16˚36.2’N, Long. 082˚47.65’E)
Regarding which side to put the wheel over the
first time, a lot has been said about putting the wheel over on the same side
as the man overboard.
Actually the amount of time it takes for a man
floating to pass the stern and the time it takes to raise the alarm and
actually to put the helm over is so vastly different that the man overboard is
very far behind the ship by the time the ship starts turning.
Please note in the case of any turning of the ship
to recover a man overboard – it is assumed that the vessel is at sea speed.
Since at a anchorage/ harbour the lowering of the lifeboat is much
more convenient.
The Scharnow Turn
The Scharnow Turn is a maneuver used to bring a
ship back to a point it previously passed through, often for the purpose of
recovering a man overboard.
The Scharnow Turn is most appropriate when the
point to be reached is significantly further astern than the vessel’s turning
radius. For other situations, an Anderson turn or a Williamson turn might be
more appropriate.
Put the rudder over hard. If in response to a man
overboard, put the rudder toward the person (e.g., if the person fell
over the starboard side, put the rudder over hard to starboard).
After deviating from the original course by about
240 degrees, shift the rudder hard to the opposite side.
When heading about 20 degrees short of the
reciprocal course, put the rudder amidships so that vessel will turn onto the
reciprocal course.
If dealing with a man overboard, always bring the
vessel upwind of the person. Stop the vessel in the water with the person well
forward of the propellers.
NOTE: All of the above turns to rescue a person
fallen overboard, the point to keep in mind is that the turns of every ship
differs from the theory. Together with the current and wind the ship may not be
actually over the position as required. As such a good look out – enough
commonsense as to the drift and that a small head in a vast ocean with waves is
very difficult to see. Even with the ship having retraced the path it may not
always be possible to see a small head in the waters. The MOB marker may drift
not always at the same rate as that of the person. SO good look out is very
essential and good common seamanship.
Sequence of actions to
take when a person is seen to fall overboard
Throw a Life Buoy with a self-igniting light
towards the person in the water.
Send a lookout aft.
Rush to the manual call button and ring the alarm
bell.
If a telephone or hand held radio is accessible
then inform the Bridge watch-keeping officer
If above not available then go up on the bridge and
inform the watch-keeping officer. Information should be as to which side the
person fell and his identity.
Actions to take when a man-overboard report is received on the bridge
Assume that you are the watch keeper:
Put the helm on the same side to the person in the
water
Throw down the Man overboard marker
Post a look out astern with binoculars
Note down the position of the ship by all possible
means
Ring standby to the engine
Inform the Master
Ring the alarm bell for Emergency
Inform on the PA system that this is not a drill
and that a person has fallen overboard.
Note down the wind direction and study the current
direction
Ask for the rescue boat to be prepared
Depending on the instructions as laid down by the
Master commence the Williamson turn
Once you see the MOB marker astern or if the
original wake is noticeable, bring the vessel back on course
Inform all ships in the vicinity of the incident
and send out a distress message
Once the vessel is on reciprocal course and the
engines are ready for manoeuvring
Slow down and if the marker is visible head for it.
When very close to the MOB, stop engines and lower
the RB.
Control measure
Select the appropriate firefighting technique: Fires on board vessels
This control
measure should be read in conjunction with Select the appropriate firefighting
technique
CONTROL
MEASURE KNOWLEDGE
To uphold the importance of
firefighter safety it is important to ensure information is gathered from all
available sources before deciding on the tactics for firefighting. Depending on
the location, type, size and severity of a fire on board a vessel, several
tactics are available to the incident commander.
Ship firefighting and incident
planning considerations should consider that any single compartment, multiple
compartments or primary containment boundary should be assessed from all six
sides of the cube where physically possible.
This may also include any preplanning
for Site-Specific Risk Information incident plans where there is a foreseeable
risk from cargo operations, roll-on-roll-off-passenger (RoPax) ship and ferry
operations, cruise terminals, etc. Where such plans exist, the incident
commander should take appropriate time to re-evaluate the assumptions and
tactics within the plan to ensure they are fit for the incident they are
dealing with.
If a dedicated UK fire and rescue
marine response (FRMR) team are handing this incident to a shore-side fire and
rescue service, then the following terms may be used to describe the strategy
and tactics employed:
Contained
The fire is extinguished or held
within an area or compartment (on all six sides) by elements of construction
(preferably fire-resisting), preventing immediate spread or endangerment of the
vessel
Maintained
The fire is 'contained' and resources
are sufficient to 'maintain' that containment through firefighting actions
(cooling, starvation, vertical ventilation or flooding)
Uncontained
The fire has breached fire resistant
construction or is burning freely, but has the potential to be 'contained', by
additional fire resistant structures, firefighting action, boundary cooling,
ventilation or fire protection systems
Uncontainable
The fire has developed to a stage
where it is not possible to hold heat and products of combustion within a
fire-resistant compartment with the resources available and uncontrolled spread
will inevitably threaten vessel safety
Firefighting options
·
Using the vessel's fixed
installations
·
Boundary cooling
·
Boundary starvation
·
Compartment flooding
·
Temperature monitoring strategy
·
Compartment smothering via lock
down/starvation
Consideration should be given to the
effects of sealing the compartment and monitoring the adjacent bulkheads/decks
and deck heads.
·
Committing fire and rescue service
personnel equipped with conventional hose lines, branches and breathing
apparatus to a compartment involved in the fire
·
Foam application
For further information on
firefighting methods refer to National Operational Guidance: Fires and
firefighting - Select the correct firefighting
technique
STRATEGIC
ACTIONS
Fire and rescue services should:
·
Have policies and procedures for
dealing with fires involving vessels, where there is an anticipated risk
TACTICAL
ACTIONS
Incident commanders should:
·
Liaise with the vessel's personnel
regarding the availability of fixed installations and suppression systems
·
Develop an intervention strategy
appropriate to current situational awareness and predicted fire development
·
Consider compartment boundary
cooling, starvation or flooding as a strategy
·
Manage the vessel's ventilation
systems in conjunction with the vessel's personnel
· Carry out an analytical risk assessment to support the decision to re-open sealed fire compartments
this is indeed informative and detailed... looking forward to your future industry related blogs-PP
ReplyDelete