Probability of grounding and collision events
The most cost-effective way to reduce risk caused by collision and grounding is to reduce the probability of these events. It is a general principle that the most effective and least costly steps for safety provisions are as far back in the series of events as possible.
The limited number of consistent, research based analyses which have been performed on preventive measures related to reducing collision and grounding probabilities generally confirms that risk control options within this area are very cost-effective compared to most other risk-reducing measures introduced by maritime authorities.
In recent years, there has been a rapid development of new navigational systems. A growing number of Vessel Traffic Systems (VTS) are established around the world. An Automatic Identification System (AIS) has been introduced, and systems have been developed for access of AIS information through the Automatic Radar Plotting Aid (ARPA). Moreover, the Electronic Chart Display and Information System (ECDIS) with and without track control has been installed on new vessels, see Vanem et al. [19]. IMO has introduced requirements for new ships to fulfil particular manoeuvrability criteria and safe levels of manning are constantly discussed. It is generally agreed that all these activities have considerable influence on the probability of ship accidents in the form of collisions, contacts and grounding. However, so far very few rational analysis tools have been available to quantify the effect of these changes.
On this background researchers work on the development of rational, mathematically based models for determination of the probability of ship–ship collision, ship collisions with floating objects such as lost containers, Fig. 5, and grounding accidents.