Transportation Safety Board Finds Large Wave Caused Leviathan II Capsizing
On June 16th the Transportation Safety Board released
its investigative report on the capsizing of the passenger vessel Leviathan II.
A summary of the report follows.
Background
On 25 October
2015, at approximately three o’clock in the afternoon, the passenger vessel Leviathan II was on a whale-watching excursion with
27 people on board when it capsized off Plover Reefs in Clayoquot Sound,
British Columbia. The subsequent rescue operation recovered 21 survivors,
which included 18 passengers and 3 crew members. There were
6 fatalities. As a result of the capsizing, approximately 2000 litres
of fuel leaked into the water.
The Operations
The operator
and owner of the vessel, Jamie's Whaling Station Ltd., has been conducting tours out of Tofino and Ucluelet, British Columbia, since
1982 and operates a fleet that included 3 small passenger vessels and
6 rigid-hull inflatable boats (RHIBs). It offers whale-watching excursions
seasonally from March to October, and approximately 25 000 passengers
travel on these vessels each year.
A
typical whale-watching trip takes 2.5 to 3 hours, and the vessels
travel various routes between the south end of Long Beach and
Rafael Point on the coast of Flores Island, a distance of approximately
28 nautical miles. These routes change depending upon weather conditions and the locations where whales and other marine
wildlife, such as sea lions and otters, are most likely to be found at any
given time. As part of the experience, in order to observe wildlife, it is not
unusual for the vessels to pass close to land, and the vessels routinely travel
near Plover Reefs.
Whale-watching
excursions are weather-dependent, and trips are cancelled when conditions are
likely to affect the comfort and safety of passengers. The company relies on
the masters to determine when a trip must be cancelled because of poor
conditions.
On 25 October 2015,
24 passengers arrived at the whaling station in Tofino for a
whale-watching trip on board the Leviathan II. The master had checked the weather forecast on
the Environment Canada website before the voyage, which was his first of
the day. The forecast predicted southeast winds at 15 to 25 knots,
becoming variable at 10 to 20 knots in the afternoon, and becoming
northwest at 15 to 25 knots in the evening. The wave-height forecast
predicted seas of 2 m, building to 3 to 4 m in the afternoon,
and subsiding to 2 m near midnight. The master also checked the wave
conditions recorded at the La Perouse Bank weather buoy. The
significant wave height was between 2.6 m and 2.9 m, with a
wave period of 9 to 10 seconds. The weather
forecast was also available at the whaling station for the information of
passengers.
While the Leviathan II was proceeding to Plover Reefs so that the
passengers could observe sea lions, there was a swell of approximately 2 m
from the southeast. On approaching Plover Reefs, the master visually
assessed the sea conditions and checked for the presence of breaking waves, in
particular at a spot south of the reef that the company's masters commonly used
to determine prevailing conditions. There were no signs of breaking waves or
aerated water or foam in the surrounding area, other than on the edge of the
reef itself.
The Leviathan II first proceeded along the south side of
Plover Reefs and then made a 180° turn and returned to the southeast
side of the reef, where the sea lions were located, to provide passengers on
both sides of the vessel with an opportunity to view them. Shortly before 1500,
the master was maintaining the vessel's position on a northerly heading
approximately 100 m off the reef in water that was approximately 7 m
deep while the passengers were watching the sea lions on the port side. As the
vessel was departing toward the north side of the reef, the master and
one deckhand heard a noise and looked aft, at which time they saw a large
breaking wave bearing down on the vessel's starboard quarter. The top of the
wave was reported to be above the flying bridge. The master reached for the
throttles in an attempt to turn the vessel to port so that the vessel would
encounter the wave on the stern. However, at that moment, the wave struck the
vessel's starboard quarter, causing the vessel to broach and rapidly
capsize.
As the vessel
capsized, one deckhand and most of the passengers fell into the water. The
master and the other deckhand were initially trapped inside the flying bridge.
Twenty-one
survivors were rescued and transferred to Tofino, where they were attended to
by emergency health services. Some of the passengers suffered from hypothermia,
ranging from mild to severe. Five bodies were recovered on the day of the
occurrence and, one remaining passenger was found on
18 November 2015.
Vessel and Personnel Certification
The Leviathan II was certified, manned, and equipped in accordance
with existing regulations.
The master and crew were adequately certified
and experienced.
The stability booklet for
the Leviathan II was approved by Transport Canada (“TC”) on
12 December 1996, and a copy was stored on board the vessel.
In order to
assess the stability of the Leviathan II at the time of the occurrence and
factors that may have affected it, the Transportation Safety Board (“TSB”) developed
a detailed computer model of the vessel and performed various stability
calculations. The conclusions of this TSB stability
assessment are as follows:
1. The modifications that were
made to the vessel since it entered service in 1996 resulted in a small change
to the estimated lightship weight and centre of gravity and did not have a
significant impact on the stability of the vessel.
2. With consumables, passengers,
and crew distributed as at the time of the occurrence, the vessel's stability
met and exceeded TC stability standards for normal operating conditions.
3. The results of the stability
assessment with applied waves are consistent with the observed behaviour of the
vessel at the time of the occurrence; that is, a rapid capsizing to port after
having been struck on the starboard quarter by a large steep wave. The
evaluation did not point to passenger load and distribution as being a likely
factor affecting the outcome of the occurrence, nor were any other possible
contributing factors identified, such as water ingress.
4. The stability standards
established by TC do not explicitly evaluate a vessel's risk when operating in
a wave environment. Although compliance with the standards implies a measure of
safety against capsizing in a seaway, the standards do not address exposure to
extreme circumstances such as large breaking waves or surf-like conditions. In
this regard, TC stability standards are consistent with international standards
in warning vessel masters that operational measures must be taken to mitigate
the risk of capsizing according to the prevailing circumstances.
4. The results highlight the
significance of encounter angle as a factor affecting the vessel's stability in
waves. Specifically, the risk of capsizing is significantly reduced when the
encounter angle is such that the vessel is meeting the wave head on.
5. The risk associated with the
absence of specific passenger controls for the Leviathan II in normal operating conditions was evaluated as low.
Cause of Capsizing
While the Leviathan II was at Plover Reefs to allow the passengers
to view sea lions, the vessel maintained a position on the weather side of the
reef, exposed to the incoming swell. As the vessel was leaving the area, a
large wave approached the vessel from the starboard quarter. Moments before it
struck the vessel, the master heard a noise that caused him to look aft and
notice the wave. However, by this point, the wave was breaking and it was too
late to realign the vessel in order to
minimize the impact of the wave. The TSB stability assessment supports the conclusion that the forces exerted on the vessel by
this wave were sufficient to overcome the stability of the vessel and cause it
to capsize; no other significant factors contributing to the capsizing were identified.
In summary:
1. While the Leviathan II was at Plover Reefs, the conditions were favourable for the
formation of breaking waves.
2. The vessel maintained position on the weather side of the
reef, exposed to the incoming swell, to allow passengers to view wildlife. As
the vessel was leaving the area, a large wave approached the vessel from the
starboard quarter.
3. Moments before the wave struck, the master became aware of
it and attempted to realign the vessel to minimize its impact, but there was not
enough time for his actions to be effective.
4. The forces exerted on the vessel by this large breaking wave
caused it to broach and rapidly capsize.
5. The
rapid capsizing resulted in the passengers and crew falling into the cold seawater
without flotation aids or thermal protection, exposing them to the effects of
cold water immersion.
6. Approximately
45 minutes elapsed before search-and-rescue (“SAR”) resources became aware
of the capsizing, as the crew did not have time to transmit a distress call
before the capsizing, nor did the vessel have a means
to automatically send a distress call.
7. The
crewmembers were able to discharge a parachute rocket, which alerted a nearby Ahousaht First Nation fishing vessel that was
instrumental in saving the lives of a number of survivors.
The TSB made the following recommendations
that:
1. The Department of Transport ensure that commercial passenger
vessel operators on the west coast of Vancouver Island identify areas and
conditions conducive to the formation of hazardous waves and adopt practical
mitigation strategies to reduce the likelihood that a passenger vessel will
encounter such conditions.
2. The Department of Transport take steps to ensure that small
passenger enterprises have a safety management system.
3. The Department of Transport require commercial passenger
vessel operators to adopt explicit risk management processes, and develop
comprehensive guidelines to be used by vessel operators and Transport Canada
inspectors to assist them in the implementation and oversight of those
processes.
4. The Department of Transport encourage all charter vessel
operators to equip their vessels with life-saving and emergency communication
and/or signalling equipment suitable for the type of operation.
5. The Department of Transport require small passenger vessels
to provide pre-departure briefings and to be equipped with a life raft that is
readily deployable, lifesaving equipment that is easily accessible, and the
means to immediately alert others of an emergency situation.
6. Transport Canada should consider whether requirements for
the use of digital emergency beacons should be applied to additional classes of
boats and airplanes.
7. The Department of Transport expedite the proposed changes to
the Navigation Safety Regulations and
expand its current emergency position-indicating radio beacon (EPIRB) carriage
requirements to require that all commercial passenger vessels operating beyond
sheltered waters carry and EPIRB, or other appropriate equipment that floats
free, automatically activates, alerts search and rescue resources, and provides
continuous position updates and homing-in capabilities.
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