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.