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Marine Safety Case Studies

The influence of maritime disasters on safety standards and the evolution of marine safety systems

The marine environment is arguably one of the most dangerous and challenging places on earth. The following case studies focus on the causes of some major marine tragedies and the new safety measures that have been implemented as a result.

Fire At Sea

The main killer in a marine fire scenario is toxic and dense smoke incapacitating persons onboard and preventing evacuation. Due to the often small and confined nature of the marine environment smoke does not have the same opportunities to disperse as it would in large building installations leading to larger and more deadly dosages of toxic fumes.

The Scandinavian Star

On the 7th of April 1990 a fire broke out onboard the Scandinavian Star ( built in France 1971 ) running between Oslo and Frederikshaven claiming the lives of 156 passengers and 2 crew members.

At around 2am fire broke out melting many of the bulkhead coverings creating a dense toxic smoke. Much of the loss of life onboard the Scandinavian Star can be attributed to carbon monoxide and hydrogen cyanide poisoning spread by the toxic smoke. The thick layer of smoke also blocked vision rendering ceiling lighting inadequate and hindering evacuation.

It is now agreed that the fire was set deliberately, however the large loss of life was down to the insufficient fire control systems onboard. For example 3 fire alarms were missing from the system, the fire alarm had to be manually held to ring, the lifeboats were in poor repair and fire doors were either in a poor state or missing.

Following the huge loss of life a number of new recommendations were made by SOLAS for ro-ro passenger ships - for example the standard fitting of sprinkler system ans the fitting of smoke detectors in stairways, bars, corridors and cabins. The recommendations also state that crew are required to be fire safety trained and the ship itself must undergo rigorous safety insections before coming into service

New initiatives were also put in place to revise the standard marine navigational vocabulary (SMNV) to which a number of crew members were not familiar and this inturn lead to incorrect co-ordinates being provided in distress calls. These initiatives eventually lead to the publishing of IMO Resolution A.918 (22) standard marine communication phrases (SMNP).

Free Surface Effect

The free surface effect involves liquids, or cargo that behaves like a liquid, altering a ships centre of gravity as it moves inside the vessel. With a large enough amount of liquid this extra moving weight can cause a ship to capsize.

Herald of Free Enterprise

On the 6th of March 1987 a number of mistakes lead to the herald of free enterprise leaving port with its car deck doors open. This allowed water to flood the deck and the free surface effect caused the ro-ro passenger ferry to capsize claiming the lives of 193 people onboard.

A number of errors leveled at the First Officer and Assistant Bosun caused the Captain, who did not have a view of the car deck doors from his position on the bridge, to leave the port of Zeebrugge heading for Dover with the bow doors still open ( the usual route for the vessel was between Calais and Dover ). The dock at Zeebrugge was not specifically designed for the spirit class ferries and as such the Captain had to fill the forward ballast tanks to allow cars to board. This in combination with the open door of the car deck lead to a maximum clearance between bow doors and water of 1.5 metres. After only 90 seconds the car deck began to flood from the bow wave and the ferry began listing to its port side before capsizing, the period of time between flooding and capsizing was less than 60 seconds.

The design of the ship also contributed to its capsizing, as a ro-ro passenger vessel relies on ease of loading and unloading for speed in port. The spirit class had an open car deck with no dividers, allowing the whole deck to flood. As the ship turned the water moved to the port side causing the centre of gravity to shift and the ship to capsize spilling its passengers into water temperatures of around 3°c.

After the event IMO released new regulations to prohibit an undivided deck of the same capacity on ro-ro passenger vessels. There are also improvements in design, with indicators from the bridge of the current position of the bow doors as well as watertight ramps and mechanisms to allow water to escape in the event of deck flooding.

MS Estonia

On the 28th of September 1994 the bow visor of the MS Estonia was not watertight while sailing from Tallinn to Stockholm, this combined with damage to the bow ramp allowed water to accumulate on the car deck of the vessel. This extra weight caused the ship to list and the crew took counter measures to rectify the list by making a sharp turn, however the free surface effect moved the centre of gravity unexpectedly. Approximately 45 minutes after the vessel began taking on water the Estonia capsized claiming the lives of 852 people onboard.

The Estonia disaster was the 44th loss of a ro-ro passenger vessel within the space of 14 years, highlighting further the flaws in the design of the vessel. Poor design also hampered the evacuation process of the vessel as it was not conformant with IMO design protocol. Of the 989 people onboard - statistics show that only around 300 people actually made it onto the deck. The position and poor communication given from the Estonia lead to a delayed rescue operation, only 137 passengers/crew were rescued as the others who made it to the life rafts had already succumb to hypothermia.

The difficulty for many of those who did not make it out of the hull was the escape route up 4 flights of stairs to reach the deck. The ships 45 degree list made the journey impossible for a number of the passengers. Another main issue were the emergency warnings issued to the crew and passengers were transmitted via the intercom in Estonian, and while the crew were mainly of an Estonian background, the majority of the passengers were Scandinavian. The lack of multilingual instructions lead to a number of people simply staying in their cabins awaiting instructions.

The large number of lives lost in this tragedy had a huge effect on the future design of ro-ro vessels with much stricter conformance required to meet IMO regulations. The most prominent change was the requirement to fit an airtight safety door behind the bow visor.

Explosion

Explosions at sea are most common on oil rigs and cargo vessels carrying hazardous materials. Owing to the confined area in which a number of systems are operating marine explosions cause large amounts of collateral damage.

Piper Alpha Platform

On the 6th of July 1988 a lack of communication between the night and day shift crew of the Piper Alpha platform lead to a series of large explosions that claimed the lives of 167 men. The Piper Field north of Aberdeen was discovered in January 1973 with the Alpha platform beginning its operations in 1976 to produce oil ( the platform was modified in 1980 to also produce gas).

Pressure safety valves on pump A were removed by the day shift crew and two blind flanges were installed into the open pipe work. The crew then finished work for the day and a permit was passed by the supervisor to inform the manager of the work undertaken on pump A. However a breakdown in communication meant the permit was never registered. When pump B tripped in the night, the nightshift crew brought pump A back into service to prevent the rig losing power and possibly losing their drill head, gas leaked from the two blind flanges and ignited causing an explosion which broke through the fire wall and set light to the oil production facility. Blast walls should have been installed when the gas conversion was made. The close vicinity of the gas and oil productions also broke the original safety design of the rig.

The crew were expecting the manager to lead the evacuation procedures from the radio room, however it was damaged by the initial explosion so no public address messages were issued. As the lifeboats were obstructed by the blazing oil fire the crew followed their training and around 100 of them gathered in the fire proofed accommodation block awaiting helicopter rescue. However the helideck was also obstructed by fire and strong winds.

The fire should have been brought under control by the rigs automatic fire deluge system, designed to suck up tonnes of seawater to extinguish fires. However the system had been switched to manual to allow divers to work without the danger of being sucked up by the strong water intakes. Two crew members did attempt to manually operate the system but they did not make it to the control panel.

The oil fire would have burnt itself out, but the back pressure from the Piper Alphas sister rigs ( Claymore and Tartan ) fueled the fire. Any stop in constant production costs alot of money and takes time to regain full production so managers on land and on sister rigs were hesitant to cut off production. There was then a break in the phone connections onboard sister rigs stemming from the explosions on piper causing another delay in the stop in production.

The pipelines used to pump pressurized gas had come under criticism from the review two years earlier. The report stated the length of the pipes mean the gas would stay at an extremely high pressure for a long time after cut-off and if ignited would be entirely uncontrollable. The oil fire melted through one these pipes causing between 15-30 tonnes of pressurized gas per second to escape and ignite causing a giant explosion rocking the rig. Fire fighting measures underway at this stage by emergency vessels had to be abandoned owing to the intense heat. One vessel was engulfed by the 150 metre wide fireball killing both crew members and 6 rig workers they had saved from the water. When a second pressurized pipeline melted the extreme heat of the blaze melted through several of the support legs causing three quarters of the rig to collapse into the sea.

The majority of the 59 survivors of the disaster ignored their training and left the dense smoke of the accommodation block and jumped between 100-200 feet into the water and swam towards rescue vessels.

A two-part enquiry was undertaken in the wake of the tragedy from which ensued 106 recommendations to offshore operators which were duly accepted. These included large safety redesigns of existing rigs, such as seabed shut off valves for gas and oil production, lifeboat entry points brought into the accommodation block as well as improvements in the placement of fire and blast walls/doors.

Conclusions

While marine regulations are constantly being amended and updated, it is often the case that maritime disasters highlight flaws and bring them to the forefront of standards committees attention. Therefore bringing about positive changes and reforms in marine standards that through conformance are designed to prevent further loss of life in the event of maritime emergency.

One of the major standards brought into force is IMO resolution A.752(18) which covers the standardization of low proximity escape route illumination to guide passengers and crew to safety. This low location illumination system aids evacuation in emergency situations and has been adopted onboard ship, oil exploration platforms, aircraft and more recently in every tall building in New York as a consequence of the tragic events of 9/11