THE LOSS OF THE STEVNS POWER
On 19th October
2003 the Anchor Handling tug Stevns Power was lost with all hands in calm
conditions while supporting the pipelaying vessel Castoro Otto offshore Nigeria.
The circumstances surrounding this event were investigated by the Danish
Authorities, whose report was published in June this year. The only response by
the marine press seems to have been 200 words on page 6 of the NUMAST Telegraph,
the first paragraph of which states “A report on accident in which an
anchor-handling vessel sank in just one minute off Nigeria has raised concerns
about commercial pressures.”
This article is therefore
intended to provide a little more information and to assist those engaged in
such tasks to operate safely.
The Castoro Otto is a ship
shape vessel built in 1976. It is almost 200 metres long and has a heavy lift
crane on the aft end. It is owned by the Italian company Saibos Construceos
Maritimas. Its task off Nigeria was to lay pipe in 75 metres of water.
There are a number of ways in
which pipe can be laid and that employed on the Castoro Otto was the most
traditional. The pipes are transported to the vessel in lengths and craned
aboard from the attendant supply vessel, thereafter the lengths are welded
together and are deployed over the stern on a fabricated ramp known as the
stinger. In order to keep the production line on the move the vessel is eased
slowly forward by means of its moorings.
The Castoro Otto has twelve
anchors, so the contracted anchor-handling tugs must move the anchors forward
one at a time. Two vessels are usually employed, one on each side and they are
constantly lifting anchors, being heaved in towards the ship then re-running
them on a new heading.
On 19th October the
Stevns Power was running anchors on the port side of the ship, and the Maersk
Terrier was working on the starboard side. On the Castoro Otto the winches are
actually operated from the Bridge and a crew member is positioned on deck
adjacent to the winch being operated to inform the winchdriver if things go
wrong. The Stevns Power had picked up No 10 anchor, and it was being recovered
towards the pipe-layer. The actions of the tug are slightly different depending
on which anchor is being deployed. The two forward anchors lead virtually ahead,
and the two aft anchors virtually astern. In these cases the tug picks up the
anchor and moves in the direction of travel of the pipelayer. In the case of the
beam anchors the tug lifts the anchor from the seabed and the Castoro Otto then
heaves the anchor in until the wire is virtually off the seabed. Up to now the
tug has been stern on the the pipelayer, but when sufficient wire has been
heaved in it will turn in the direction of the new anchor position and begin to
move in the direction of travel of the pipe. Soon there-after the winchdriver
will begin to pay out the wire. This action saves a minute or two in the
Also present at the location
was the pipe carrier the Oil Trader which was tied up the the Castoro Otto on
the starboard side and the survey vessel the Inspector which was trailing astern
of the pipe layer checking the pipe on the seabed with an ROV.
The report on the loss of the
Stevns Power states that at 1705 the tug had lifted No 10 anchor off the seabed
and that the mooring was being recovered at 1710. At 1715 the Stevns Power began
to move towards the new anchor position by canting the ship to port with the
intent finally of moving astern in the direction of travel of the pipe.
At this time the report states
that “the Third Officer (at the winch) saw that the Stevns Power began to heel
over to port side and a bit to the stern. Thereby the Stevns Power got a more
The 3rd Officer
spoke to the bridge telling them to stop heaving because it was apparent to him
that the tug was in trouble, and the winch operator immediately stopped the
winch. However, the report goes on to say that the Chief Officer “saw that the
Stevns Power heeled over to port and was taking in water on the aft deck in the
port side. Immediately after Stevns Power heeled over to one side and sank very
fast with the stern first.”
There were no survivors.
The Stevns Power, and its
sister ships are well known to everybody who has worked in the marine sector of
the offshore industry. It was originally the Maersk Beater and together with
five sister ships supported pipelayers and exploration rigs from 1976 onwards.
They were a ship type which was briefly in favour because due to their small
size and relatively high power, they were able to carry out anchor-handling
operations faster than the conventional anchor-handlers of the period, which
always had trouble with windage, and deck length. One of its sisters, the Maersk
Battler was the first ship to grace the pages of this website in 1998. Later the
Stevns Power was photographed by Oddgeiri Refvik for us when it was at the
Seaway Falcon off Egypt. The latter photograph was been used by the Danish media
at the time of the event and in fact in the Danish Government report (All
The crew of the tug consisted
of three Danes, six Phillippinos and two Congalese. The Master had considerable
experience in the business, the Mate was on his first trip on an offshore vessel
and the Navigating Officer (2nd Mate) was on his second trip on the
Both the Engineers and the
Motorman were from the Phillipines and all had served on anchor-handlers before,
two of them having undertaken several trips on the Stevns Power. One of the ABs
had also done a previous trip on the ship and the Cook and the Second AB had
just signed on.
The two Congalese were
required to be there by the Republic of Congo, part of the usual agreement in
Africa to employ persons native to the country where the units are operating.
Lacking anyone to talk to from
the ship the Danish investigators interviewed personnel from the other
anchor-handler, the Maersk Terrier, the Inspector and a number of former Masters
of the ship and some other Danish anchor-handler masters.
The results of these
discussions and the interviews with the crew of the Castoro Otto, indicate that
the Stevns Power was probably trimmed too far by the stern and that the engine
room escape hatch at the port aft corner of the ship was probably open. The
mooring was being recovered at high speed and on a number of occasions including
the day of the accident the Stevns Power had indicated to the Castoro Otto that
the recovery speed of the moorings gave them problems.
From the various calculations
and observations which too place the Danish investigators have determined that
the speed of recovery of the mooring resulted in the Stevns Power travelling
astern at a speed of between 6 and 8 knots.
In all accidents there are
many factors which must be concurrently in place for them to occur. We usually
suggest during our major accident risk assessments that overtaking a bus on a
blind right hand bend is not in itself dangerous. There has to be a vehicle
coming the other way. And the Danish Investigators explored all aspects of the
disaster from the requirement to conform with the ISM Code, to the possibility
of fatigue, considering that the ships were continuously carrying out
anchor-handling operations with the whole crew working six on six off. But
finally they decided that the factors to be considered in the case of the Stevns Power included the following – in no particular
order (my words):
The tug was trimmed too far by
the stern, giving little freeboard at the roller.
The speed of recovery of the
mooring was extremely fast.
The Safety Management System
of the Company did not mention anchor-handling.
It is possible that the
rudders went hard over due to the influence of sternway.
It is possible that the Master
of the Stevns Power failed to react by operating engines or the winch when
The Chief Officer lacked
necessary training in anchor handling.
Regardless of all of the above
there was a single factor which could have prevented this terrible tragedy. This
is stated in the report as follows:
“AN OPEN HATCH AND MAYBE OPEN
WATERTIGHT DOORS RESULTED IN WATER FLOODING THE ENGINE ROOM. THEREFORE THE
VESSEL SANK VERY FAST.”
You guys out there, remember
the first principle KEEP YOUR SHIP WATERTIGHT.
Victor Gibson. October 2004.
Stevns Power Photograph Oddgeir Refvik
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