Accident Investigations at Sea (World of Forensic Science)
Accidents can occur anywhere that there are people operating machinery. The world's oceans are no exception. Sea-going accidents have been a consequence of maritime tradition ever since boats put out to sea thousands of years ago.
Even in the early days of seafaring, there was interest in determining how an accident occurred and in seeking ways of preventing similar occurrences. These investigations eventually became official duties of the government, for example, in Britain formal marine accident inquiries were established approximately 150 years ago. Today, the investigations of sea accidents can reply on the skills of forensic scientists and the various technologies they can bring to bear.
When a seagoing accident involves an injury or fatality, an investigation can be very similar to that conducted on land. The object is to determine the cause of injury or death. Photographs of all the areas of the ship that are relevant in the investigation will be taken. The accident scene will be carefully scrutinized to recover any evidence and witnesses will be interviewed. All these steps help to piece together what occurred.
But an accident investigation conducted at sea presents some unique challenges. If the ship is still at sea, then the rapid transport of the samples to a laboratory for analysis may not be possible. In that case, the samples need to be stored so as to prevent tampering and deterioration. In the case of biological samples like tissues and blood, storage on ice at refrigerator or freezer temperatures can be options.
Other facets of an accident investigation are not concerned with injuries, but with the damage caused to the vessel. By analyzing the pattern of a fractured hull, for example, inspectors can gain an understanding of the cause of the damage. A gashed hull caused by a collision with an iceberg will be different than the damage caused by an impact with another vessel. A skilled forensic naval architect is able to examine a damaged vessel (a bent propeller shaft, for example) and determine the cause of the damage.
An accident investigation can involve the recovery of materials that have been dislodged from the vessel into the surrounding water, or of an entire sunken vessel. Some material may be floating on the surface. Then, recovery of the flotsam involves a surface search, usually by means of a search boat. Divers or submersible craft may also be used to locate debris that has sunk to the bottom of the ocean. In deep water, this process can be a very complex and dangerous activity.
In the investigation of an accident or crime on land, the investigative team often consists of more than one person. But, in the depth of the sea, only a single diver may be present. The diver must handle an object to identify it and determine its position on the sea floor. Once back at the surface, the diver must report on what was seen. The smallest detail can be important in guiding further recovery efforts and in piecing together the course of events. So, an investigative diver must be meticulous and attentive to detail.
Subsequent efforts can utilize sonar. This under-water version of radar sends out pulses of energy and displays the pattern of returning echoes to obtain images of underwater objects.
A critical facet of a marine accident investigation is collecting information on the weather patterns around the time of the accident. The value of this approach is exemplified by the investigation of the November 10, 1975, sinking of the freighter SS Edmund Fitzgerald in Lake Superior. The tragedy, which killed 29 mariners, formed the basis of a song by the Canadian singer/songwriter Gordon Lightfoot. By analyzing the ship's course and wind patterns, investigators determined that a shift of wind during a fierce mid-winter storm took the ship away from the protection of nearby land and put the vessel directly in the path of huge waves.
That investigation also exemplified the value of collecting and analyzing all communications that occur between the affected vessel and other vessels, aircraft, and the shore. In the case of the Edmund Fitzgerald, it was established that the captain was not aware of the severity of the threat until the ship became swamped with water and sank.
Simulations of the accident can be a useful way to reveal potential causes of an incident. Computer programs can be used to carry out simulations. As well, models of the affected vessel can be constructed and positioned in a specially constructed pool that can generate waves. The National Centre for Inland Waterways, located in Burlington, Ontario, Canada, has a pool where such testing can be carried out.
Another technology that has been advocated and is becoming more popular is the voyage data recorder. Akin to the flight recorders that are a standard on aircraft, a voyage data recorder provides information on various aspects of the ship during the voyage. A meeting of the International Marine Organization held in December 2004 was expected to pass amendments to the 1974 International Convention for the Safety of Life at Sea (SOLAS) requiring the presence of voyage data recorders on cargo ships.
SEE ALSO Accident reconstruction; Chemical and biological detection technologies; Drowning (signs of).