Getting scientific
MOST lawyers and insurance claims handlers will need to use engineers to investigate maritime incidents at one time or another. In many cases, the instruction will be for a routine cause, nature and extent of damage investigation. In such cases, the cause of the incident is not always of prime concern. Indeed, particularly immediately after an incident when security is being arranged, the cause may be of secondary importance to determining the nature and extent of the damage.
There are a number of difficulties that can arise when litigation commences if the cause has not been investigated adequately. Where there is an overriding need to consider the cause of an engineering failure, fire or other scientific problem, there is, therefore, considerable merit in engaging a forensic engineer or scientist to consider the cause in isolation.
The benefits of engaging forensic engineers include:
- They will be skilled in collecting and recording evidence in a manner that will withstand scrutiny;
- They will be well-acquainted with their duties as experts and with their duty to the court;
- They will be aware of the importance that a court may attach to their role.
A good forensic engineer will investigate any incident in a structured, scientific manner. An investigation will typically be planned and investigate as set out below although, in simpler cases, it may be abridged.
Step 1
Carry out a preliminary examination of the incident locus, including relevant areas peripheral to the damage, with minimal disturbance. Obtain relevant plant data and interview readily available witnesses. Develop a working hypothesis to explain the possible causes(s).
Step 2
Carry out a systematic and more detailed examination of the incident locus, involving disturbance where necessary. Obtain further witness evidence together with relevant documentary information. Identify and preserve items or components for bench examination, testing and detailed laboratory analysis.
A good forensic engineer will continuously test the working hypothesis against the new evidence as it emerges. He will modify or even discard the original hypothesis if the new evidence so dictates. Ultimately, after due consideration, a final view on the cause(s) of the incident will be reached.
Step 3
Test the view formed from the scene examination by the application of a theoretical analysis, calculations or simulation, as appropriate, and adjust the view to meet the conclusions of such tests.
A practical example
The following fictional case study shows how, in the simplest terms, the process described above is applied in practice.
The study considers the collapse of the jib of a deck crane during cargo operations. With a simple mechanical failure, the preliminary investigation would be restricted to ascertaining the nature of the damage sustained, documenting the position of significant items such as the jib and the grab, and a first inspection of accessible fracture surfaces and other critical components.
The incident involved the collapse of the crane jib and the failure of the luffing wire. From the available evidence, a hypothesis formed at this point would be that the collapse occurred due to a failure in the luffing wire as a result of overload, allowing the jib to fall into the hold.
In such an elementary case, most witnesses would be interviewed once. The interview process would, therefore, bridge the preliminary and detailed inspections. For the sake of the example, let’s say the deck officer revealed that the stevedore operating the crane has swung the jib so as to cause the grab to extend outside its normal reach to access cargo at the opposite end of the hold, rather than use a mini-excavator to move the cargo to the grab. Because such an action increases the load on the luffing wire, the witness evidence reinforces the hypothesis formed during the preliminary examination and provides further avenues for enquiry.
Detailed inspection would involve the examination of the fracture surfaces on the boom and the failed sections of the broken wire. The reach of the crane would be determined and the position of the grab, relative to the crane, would be carefully measured. The failed wire would be of critical importance and examined in situ – Labelled samples would be retained so they would be subjected to bench examination to evaluate their condition and to laboratory analysis to ascertain why they had failed. Samples of wire would also be load-tested, if appropriate, at a suitable test house. Following repairs, the safety devices on the crane would be tested.
After careful consideration, alternative causes, such as the deterioration of the luffing wire, would have been eliminated and it would have been shown, by means of critical analysis, that the luffing wire had failed because of the way in which the stevedores had operated the crane. The principals would, therefore, be in a position to consider pursuing a recovery action.
It would be possible to ascertain the loading on the luffing wire, in the abnormal way in which the crane was operated, by carrying out mathematical modelling.
The forensic engineering methodology described above could be applied to a wide range of equipment including main and auxiliary engines, cranes, derricks and lifting equipment, turbines and turbochargers, propulsion systems, electrical equipment, pressurised system component failures, tank coating failures, structural damage to vessels, sinking and the total loss of vessels, fires and explosions, and liquid and dry cargoes.