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Friday, July 14,
2000
U.K. publishes report
on "killer wave" accident
Britain's Marine Accident Investigation Branch (MAIB) has now
published its official report into the man overboard fatality
from the angling boat Purdy, at Shipwash Bank, off Harwich, on
July 17, 1999.
This was the incident that gave rise to headlines about high
speed ferries generating "killer waves," after the
Purdy reported that it had been swamped by a very large wave,
with one person lost overboard.
According to the MAIB, Purdy, a 10 m long,
Aquabelle angling boat with the skipper and one guest on board,
was preparing to anchor and begin fishing on a shallow sandbank
off the East Anglian coast when the Stena Discovery high-speed
ferry passed inbound for the port of Harwich. Purdy's skipper
turned his boat towards the wash from the high-speed ferry.
The weather was fine with good visibility
and a slight sea. As the first wash waves approached Purdy they
appeared to grow in height to 4 m and begin to break. The first
wave crashed over Purdy's bow swamping the vessel and washing
the guest, a John Sibley who had been sitting on the engine casing
aft, overboard.
The skipper threw a lifebuoy towards the
man in the water and tried to maneuver the boat towards him.
The man disappeared from view.
Despite extensive searches carried out
by the skipper and the rescue services, his body was not recovered
until 12 days after the accident. He had been wearing heavy leather
boots and no lifejacket.
An interim recommendation was addressed
to both the U.K. Maritime and Coastguard Agency (MCA) and Stena
Line BV to carry out route assessment trials with respect to
wash generation.
The MAIB is now making further recommendations
to the MCA to ensure that all operators of high-speed craft
undertake route assessment trials with respect to wash generation
as a requirement for issuance of a Permit to Operate. Guidance
criteria should be developed on maximum permitted generated wave
heights for measuring the efficacy of the route assessment results.
The MAIB's findings are
- The victim was washed over the side from
Purdy at about 0936 on 17 July 1999 by a large wave.
- The victim was not wearing a lifejacket.
- Purdy was well equipped and maintained.
- Purdy's skipper was very experienced,
although unqualified.
- At the time of the accident, there was
a southerly wind of force 3, good visibility and a slight sea
and swell.
- It is likely that Purdy had less than
3 m of water beneath her keel and possibly less than 2 m.
- Stena Discovery had passed just over a
mile from Purdy about 3 minutes before the wave struck.
- Stena Discovery had been operating on
the Hoek van Holland/Harwich route since June 1997.
- High-speed craft, like Stena Discovery,
were known to have the capability to produce waves that can be
accentuated and become dangerously high in shallow water.
- Stena Discovery had a valid Permit to
Operate, which covered the port of Harwich.
- Stena Discovery's route and speeds on
approach to Harwich had been revised several times in response
to information about incidents on the beaches and some off-lying
banks.
- The changes to Stena Discovery's approach
had been largely successful in reducing the impact of waves on
the beaches to within acceptable limits.
- On July 17, 1999, Stena Discovery was
operating on a route and at speeds in accordance with the current
guidance.
- Very little feedback had been received,
before the accident, about the danger of wash waves on off-lying
banks. However, attempts had been made to give appropriate warnings.
- Purdy's skipper was not aware of warnings
concerning the danger of Stena Discovery's wash on off-lying
sandbanks.
Causes
The accident occurred when a wash
wave, generated by HSS Stena Discovery and having grown to about
4 m in height as it encountered the shallow waters on the southern
end of the Shipwash Bank, broke over and swamped the angling
boat Purdy.
- The wave was generated by Stena Discovery
during or after the alteration of course made to the south of
South Shipwash buoy. Its height and steepness were probably accentuated
by focusing due to the particular bathymetry and superposition
with wash waves generated before the turn.
- The skipper of Purdy had not been aware
of the broadcasted dangers associated with shallow banks and
the passage of Stena Discovery.
- The skipper had placed Purdy in a dangerous
position with regard to the wash waves that Stena Discovery was
known to produce.
- The victim was not wearing a lifejacket.
Had he done so, his chances of survival would have increased.
- The skipper could have done more to ensure
the safety of his boat and her occupants.
- Wash generation by HSS 1500s is complex
and is not yet fully understood.
- It is likely that Stena Line BV was aware
that wash would impact on Shipwash Bank and that the Bank would,
to some extent, protect the bathing beaches at Dovercourt and
Felixstowe. However, it did not expect waves of 4 m height to
be produced.
- There was a shortfall in safety management
by Stena Line BV in that no documented risk assessment of the
route with regard to wash generation was carried out prior to
Stena Discovery commencing operations, despite prior knowledge
of the problems being experienced on Irish Sea routes.
Recommendations
During the course of the investigation,
in August 1999, the following safety recommendations were issued:
The Maritime and Coastguard Agency was
recommended, as an interim solution, (1) to insist, through the
Netherlands Shipping Inspectorate, that Stena Line Holland BV:
instruct masters of the HSS ferry to change
their passage plan and reduce speed to ensure safe entry to Harwich
Haven including the reduction of wash on adjacent sandbanks;
(2) begin monitoring the wash in the approaches
to Harwich Haven, to ensure the action taken reduces it to within
safe limits.
Additionally, the MCA was recommended to
(3) instigate through the Thames Coastguard,
a marine safety broadcast on VHF radio to warn small boat users
of the dangers associated with the wash of the HSS.
Towards a permanent solution, MCA, was
recommended to (1) insist, through
the Netherlands Shipping Inspectorate, that Stena Line Holland
BV carry out a full risk assessment of the approach to Harwich
Haven with reference to wash and, as a result, propose a route
and speed profile that constitutes a permanent solution; and
(2) liaise with the Netherlands Shipping Inspectorate
to ensure that the Permit to Operate and Route Operations Manual
are endorsed with the requirement for a full risk assessment
with reference to wash, and for all likely areas of wash to be
identified, and action taken to avoid it.
In recommendations to small boat users,
the MAIB reminded all users of small
craft of the dangers that can arise unexpectedly from the wash
of passing vessels. In deciding whether to wear lifejackets,
it should be remembered that no harm comes from wearing them
in even the most benign conditions, and that they may save lives
if an unexpected event occurs.
Other recommendations made at the completion
of the investigation:
The Maritime and Coastguard Agency is recommended
to:
- consider instigating procedures whereby
a full route assessment with respect to wash is undertaken by
all operators of high-speed craft who apply for a Permit to Operate;
- consider establishing maximum wave height
criteria for measuring the efficacy of the route assessment results;
- consider the implementation of international
regulations in this respect by raising the subject at the International
Maritime Organization when the High-Speed Craft Code is next
reviewed.
The Hydrographic Office is recommended
to:
- Review the content of Admiralty Notices
to Mariners Number 23, to give appropriate warning concerning
the risks of large waves on shallow off-lying banks.
U.K. Maritime and Coastguard Agency
response
In a statement today, the MCA notes
that the recommendation that operators of high-speed craft who
apply for a permit to operate undertake a full route assessment
with respect to wash is now a condition of the Permit to Operate,
which is issued to all operators of High-Speed Craft operating
in U.K. ports.
The MCA says it is considering the recommendation
that it establish maximum wave height criteria for measuring
the efficacy of the route assessment results.However, the MCA
believes that the risk assessment approach allows for flexibility
in terms of the differing requirements of an area and along specific
areas of a route.
On the recommendation that it raise the subject of appropriate international
regulations at IMO, the MCA notes that it is proposing
to submit a paper to IMO later this year. This paper will draw
on a research project commissioned by the MCA and aims to inform
the next review of IMO's High Speed Craft Code.
Cammell Laird to refurbish sub for Canada
Britain's Cammell Laird has won a contract from BAe Systems to
support the maintenance of former Royal Navy submarine, HMS Unseen,
for the Royal Canadian Navy.
HMS Unseen is an SSK Upholder (Type 2400)
diesel-powered conventional submarine built at Birkenhead for
the Royal Navy. It is one of four conventional submarines that
are to be transferred from the Royal Navy to the Royal Canadian
Navy over the next few years, All four have been mothballed
since the mid-nineties following the U.K.'s decision to pursue
an all-nuclear submarine policy.
BAe Systems, Barrow-in-Furness, was awarded
the contract from both the Royal Navy and Royal Canadian Navy
to reactivate, refurbish and modernize all four submarines prior
transfer to Canada. The transfer involves a lease/purchase deal
between the UK and Canadian Governments.
The HMS Unseen was launched in 1989 and
is one of the many submarines originally built at Cammell Laird's
Birkenhead shipyard in the 1980's and has returned to her birthplace
for drydocking prior to transfer to the Royal Canadian Navy.
The submarine arrived in Cammell Laird's
Merseyside yard on July 4th and is expected to stay in dry dock
for some 40 days prior to transferring to the yard's wet basin
for a further 15-20 days. During the drydocking period, work
will include renewal of the tailshaft bearings as well as a few
other repair and refurbishment items required while the vessel
is out of the water. It will then undergo trials and crew training
at the yard's wet basin prior to sea trials.
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