1) Stopping the main engine and drifting without malfunction does not constitute an "exceptional circumstance" allowing a vessel to transmit an NUC signal under COLREGS. 2) The collision between MOL Maneuver and Zhen He was caused by both vessels transmitting improper NUC signals while drifting and failing to maintain a proper lookout. 3) Transmitting an NUC signal while drifting provides no benefit and does not relieve the duty officer of responsibility for collision avoidance. Maintaining a proper lookout and communicating with approaching vessels is still required.

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Stop main engine without any
malfunction of propulsion, drifting
and transmit “not under command”
signal not relieve deck officer from
duty of the watch
HÀ NAM NINH
Abtract
• At many ports over the world, especially Japan
ports, many ships have to stop engine, drifting
to wait for berth schedule. Almost of those
drifting ships transmit “not under command”
signal. However, that activities are not correct
as per COLREGS and also do not release deck
officers from responsibility of avoiding
collision.

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Definition of “Not Under
Command” (NUC)
• COLREG72, Part A, Rule 3, (f): The term
"vessel not under command" means a
vessel which through some exceptional
circumstance is unable to manoeuvre as
required by these Rules and is therefore
unable to keep out of the way of another
vessel.
Not Under Command signal

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A conversation between ships
A conversation between ships
• O.M.: We are crossing and existing a risk of collision. Please
alter your course to your starboard and pass my stern.
• G.L.: Oh… no… no… I am “not under command”, you have
to avoid me.
• O.M.: You are “not under command”? Is that true? Okie! If
you are true in “not under command”, I will contact to
USCG and request them to support you.
• G.L.: Oh… no… sorry! I am just stop main engine, drifting
and waiting for berth schedule. I have take time to start
engine. Please avoid me!
• O.M.: Okie! You are stopping engine. I see. I will avoid you.

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Alaska Maritime Prevention &
Response Network
Alaska Maritime Prevention &
Response Network
• “The master shall ensure the vessel’s Automatic
Identification System (AIS) is transmitting accurate
information, including the vessel’s type, dimensions
and destination. Additionally, the AIS shall transmit
proper information regarding the vessel’s operation.
“Not Under Command” shall not be transmitted unless
a vessel has encountered “extraordinary
circumstances” that interfere with the safe navigation
of the vessel as per the International Rules of the Road.
The Network will contact the ship when AIS
transmissions of “Not Under Command” are broadcast
to determine the nature of the problem the vessel is
experiencing.”

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MOL Maneuvercollied with Zhen He
• On 22nd FEB 2012, The 302 meter long,
78830 dwt container ship MOL Maneuver
collided with the 275 meter long, 51985
dwt container ship Zhen He in the South
China Sea near Hong Kong.
MOL Maneuvercollied with Zhen He

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MOL Maneuvercollied with Zhen He
MOL Maneuvercollied with Zhen He

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Zhen He transmit NUC signal
• Z.H. used NUC signals during their 12 hours waiting for berth. The Master
of ZH ordered his crew to display NUC signals through the vessel's
Automatic Identification System (AIS) and to exhibit NUC shape on the
vessel's mast. Half an hour before the accident when the Chief Officer
came to take the control of the vessel, he expressed no objection to the
NUC signals. Neither did other crew members that were in the wheel
house at the time of the accident. Before the incident, the duty officer,
the Chief Officer, was speaking with the sailor about his prospective
retirement life without noticing the deteriorating visibility and
approaching M.M. The Master was walking around the wheel house, and
he also did not recognize the risk of collision with M.M. Two minutes
before the accident, the Chief Officer heard the whistle of M.M. and
asked the Second Officer what was the sound signals for NUC vessels.
The Second Officer replied that there is no such signal as provided by
COLREGS. Seconds before the accident, another prolonged blast was
heard by all those in the wheel house but it was too late to avoid the
collision.
MOL Maneuvernot diligent enough
• M.M. had been steering at about 17.5 knots by auto pilot until the collision
happened. About 22 minutes before the accident, the Chief Officer sighted a
fishing vessel narrowly cleared MM's starboard at a distance of only about 150
meters. At that time, there were dozens of radar targets, including Z.H., lying
ahead near M.M.'s planned route. The Chief Officer's attention was heavily
attracted by the nearby fishing vessel traffic. Although Z.H. was detected on the
radar, the Chief Officer thought Z.H. was a fishing vessel, and he paid no special
attention to it. About 19 minutes before the accident, as per the instruction of the
Master, the Chief Officer started to execute Restricted Visibility Check List at the
table. At the same time, he instructed the duty sailor to go outside the wheel
house for watching the fishing vessels at M.M.'s port side. Two minutes later, the
visibility continued to deteriorate, and the Chief Officer ordered the duty sailor to
sound fog whistles as per COLREGS. The sailor did so and M.M. had since then
been sounding at an interval about 1 minute one prolonged blast. Afterwards,
the Chief Officer once again ordered the sailor to check the fishing vessel on the
vessel's port side. The sailor did so again failed to see anything due to the
heavy fog. He reported the same to the Chief Officer and then came to the radar
finding Z.H. was ahead at only 4 miles. He reported his finding but the Chief
Officer only replied he was noted and continued his job of Restricted Visibility
Check List. Seconds before the accident, the sailor shouted "a ship in front" but
it was too late to avoid the collision.

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MOL Maneuvercollied with Zhen He
MOL Maneuvercollied with Zhen He

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MOL Maneuver collied with Zhen He
• Some holds on the starboard of “Zhen
He” were seriously damaged, and five
40-feet containers fell into the sea and
some containers were broken or twisted.
The upper part of the bulbous bow
of “MOL MANEUVER” was broken. There
were no injuries among the crew
members onboard the vessel, and no oil
leaks have been detected.
Discussion
• Drifting can be considered as NUC? As
common understanding among deck officers,
when cannot control the ship’s course and
possition the ship will be considered as NUC.
As my opinion when engine stop and ship
drifting without any malfunction of ship’s
propulsion system is not the case of
exceptional circumstance

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Discussion
• Drifting, transmitting NUC signal, Do we get
any profit?
– When transmitting NUC signal, duty officer will
arise lazy behaviour and put his safety and all
other crews into someone’s hands.
– If drifting, speed is too small, the other ships
approaching are so easy to recognize if duty
officer diligent enough.
– If collision happening, the ship drifting with NUC
signal will be exempted from responsibility? The
answer of the court is NO.
The History
• In the past, after finishing engine and drifting,
it took rather time for re-starting M/E. This
might be the first reason for the considering of
NUC.
• 20 years ago, ARPA and AIS were not equipped
on board, therefore it was not easy to
recognize some ships drifting or not. They
might consider transmiting NUC signal for
more easy understood.

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Conclusion
• As discussion, we can find there is no profit
when drifting with NUC signal. The duty
officer might be lack of necessary diligence for
keeping safety.
• Therefore during drifting, duty officer should
continuous keep activities as underway with
propulsion and have to warn the approaching
ships by the all means of communication such
as signal lamp, whistle, VHF channel 16.
Thank you for your attention!