In a report issued this morning, the IFA 1 cable
carrying electricity between the UK and France was damaged due to a series
of factors that included weather, vessel collision, defective equipment,
out of date charts and systemic failures.
At approximately 0850 on 20 November 2016, the general cargo ship Saga
Sky collided with the rock carrying barge Stema Barge II about
2 miles off the south coast of the UK. Both vessels were being driven towards
the coast under the influence of adverse weather conditions created by
Storm Angus, during which time two subsea power cables were severed.
Stema Barge II was being used to supply rock armour to a sea defence
project commissioned by Network Rail. The barge had been anchored close
to the subsea cable runs of Interconnector France-Angleterre 1, a high
voltage power supply system operating between the UK and France. After
Saga Sky had passed through Dover Strait in the south-west traffic
lane, the weather deteriorated significantly with the approach of Storm
Angus. The south-westerly wind and tidal stream significantly reduced the
ship’s progress. The master attempted to turn the ship to starboard to
steer a reciprocal course and run with the weather until the storm abated.
The effect of the wind acting on the ship’s cranes and aft superstructure
overcame the turning moment of the rudder and prevented the turn from being
completed.
Despite maintaining propulsion, Saga Sky
was blown broadside over a distance of approximately 7.4nm while the master
continued with his attempts to turn the vessel to starboard until it collided
with Stema Barge II. The combination of wind and tide propelled
Saga Sky, beam on to the wind, at speeds of up to 9kts, and even
after deploying both anchors the ship continued to move under the effects
of the storm.
Both vessels dragged their anchors and two of the four subsea cable pairs
that made up the interconnector were severed. The investigation examined
the reason for Saga Sky continuing to proceed in adverse forecast weather
conditions, and the rationale for the master’s attempted turning manoeuvre.
It found deficiencies with the ship’s weather forecast reception facilities,
deficiencies in the sea defence project planning process, and potential
shortfalls in the provision of emergency response assets.
The report made a number of recommendations including:
That the Marine Management Organisation improve
its marine licence application process;
The United Kingdom Hydrographic Office (UKHO) promote the International
Hydrographic Organization’s (IHO) recommendation for implementing anchoring
restrictions near subsea cables;
That the Maritime and Coastguard Agency, to commission a study to review
the full range of emergency response assets available in the Dover Strait
area and in conjunction with the UKHO to justify the need for regulatory
powers which could be applied, where appropriate, to ensure vessels comply
with IHO recommendations made in respect of anchoring restrictions near
subsea cables.
That Saga Sky’s manager enhance its shipboard procedures in respect of
heavy weather operational guidance.
Specific findings were
1. The marine licence granted by the MMO referred only to the sea defence
works and did not formally take into account operations away from the foreshore.
2. In referring the marine licence application to the MCA, the MMO provided
no detail on the objectives of the MCA’s review or what it required the
MCA to assess.
3. Lack of focus on navigational risks - An out of date chart had been
used for the method statement, passing through the project planning phase,
including the marine licence application, without being questioned. The
chart used by Stema Shipping UK Ltd was dated 21 March 1980 and consequently
did not show the subsea cables of IFA 1 which were were first charted on
the 10 July 1987 edition, although 9 years prior to the incident.
4. No UK Minimum distance from submarine cables required when anchoring
or conducting other underwater activities.
5. Lack of statutory powers for the MCA to impose criteria for the protection
of subsea infrastructure.
6. Saga Sky’s weather fax and Navtex receiver were defective, limiting
the vessel’s ability to receive live and forecast weather information.
7. In the absence of vessel-specific guidance as a reference for assessing
the effect of forecast weather conditions would have on Saga Sky’s
manoeuvrability, the master was reliant solely on his own knowledge and
experience.
8. Even if the French tug Abeille Languedoc had been tasked as early
as 0700, when the master decided to turn Saga Sky to run down sea,
it would not have arrived in time to prevent the vessel from colliding
with Stema Barge II. It is also unlikely that it would have been
able to prevent Saga Sky from running aground had the ship avoided
Stema Barge II.
9. The lack of any suitable tug assets in the vicinity of Dover meant that
Anglo-Eastern Ship Management Ltd would not have been able to engage a
commercial salvor in time to avert Saga Sky’s collision (or possible
grounding).
10. Ships’ crews who encounter difficulty in severe weather conditions
within navigational constraints may have insufficient time in which to
arrange for a commercial tug in the normal way (given commercial and availability
considerations).
11. A ship’s anchors will be used in extremes in an attempt to prevent
it from running aground (regardless of any restrictions on anchoring) with
consequent potential damage to subsea cables and other seabed infrastructure.
12. Given the volume of traffic using the Dover Strait and the apparent
absence of local commercial salvage assets, it would be appropriate to
review the availability of emergency towage provision in the Dover Strait,
as has already been done for north 34 and north-west Scottish waters.
Other Safety issues contributing to the accident included:-
1. It is possible that a cable burial depth of more than 1.5m would have
been decided had the BPI methology been available and taken into account
at the time of IFA 1’s construction.
2. With no planned maintenance or condition surveys carried out on IFA
1, changes to the seabed and consequent cable exposure are likely to have
gone unnoticed.
3. In view of the reconstructed tracks of Saga Sky and Stema Barge II during
the period leading up to and during the accident, and supporting images
from seabed scans, it is concluded that their anchors probably impacted
with the cables of IFA 1 at the points where damage occurred.
4. In not acting on the deteriorating forecast weather conditions, Saga
Sky’s master underestimated the risk of the weather overpowering the
ship, particularly as its ballast condition resulted in a large windage
area.
5. It is apparent that Saga Sky’s master was more focused on the
second low pressure system than on the more immediate threat in the form
of Storm Angus.
6. Despite several prompts by CGOC Dover to consider deploying the ship’s
anchors to arrest the drift, Saga Sky’s master was initially of
the opinion that conditions were not safe to allow an anchor party to operate
on the forward deck.
7. Heaving to, deploying one or more anchors and seeking tug assistance
remained available options. However, the master remained confident in his
ability to turn the ship around and so took none of them until Saga
Sky was at imminent risk of colliding with Stema Barge II.
8. The Port of Dover tugs did not possess the capability to safely operate
under the severe conditions outside of the harbour breakwater.
