Shipping Inspections, Detentions, and Accidents: An Empirical Analysis of Risk Dimensions

Inspections play a key role in keeping vessels safe. Inspection authorities employ different policies to decide which vessels to inspect, including type of vessel, age, and flag. Attention for vessel history is usually restricted only to past detentions. This paper shows that it helps to combine past detention with past accident information to target risky vessels for inspection and to prevent serious and very serious accidents. Five methods are presented to classify risk of vessels based on these two risk dimensions, i.e., detention risk and accident risk, each of which involves an extensive set of risk factors. It is shown that these classification methods have predictive power for future serious and very serious accidents. Compared to using only detention information, incorporation of accident risk improves inspection hit rates for vessels with future accidents by 30-50%, depending on the applied inspection rate. It is recommended to focus on vessels where both risks are relatively high. A practical example shows management implications for inspection authorities how to prevent missing risky ships and how to prioritize inspection areas defined in terms of eight risk domains that include collisions, groundings, engine and hull failures, loss of life, fire, and pollution.