**1. Introduction**

A dynamic positioning (DP) system is a piece of automation in which data from wind, currents and ship motions are taken from different sensors. After analysing them, a signal is sent to thrusters and rudders to compensate for those movements. This system seeks two main goals depending on the nature of the operations in progress: maintaining a given position or moving a vessel along a pre-set track.

The DP system has been in use for many decades, and its applications are primarily used in the offshore industry. The complexity and high accuracy requested for the different offshore operations make the dynamic positioning system a valuable tool for this sector.

However, rarely does such a sophisticated automated system always performs smoothly. The study of the incidents reported by vessels is vital to discover any failures that could be corrected and to improve the safety of DP operations.

The International Marine Contractors Association (IMCA) is, without any doubt, one of the most prolific authors to the cause of safety in DP operations. They have published different recommendations to the industry, along with guidelines for operations, sensors, and personnel. It is also important to mention the collection of DP incidents that IMCA has published since 1994. The high volume of DP incidents reported anonymously, and carefully published by IMCA, has been the base of this research.

In this chapter, the focus is set on the research of the incidents reported to IMCA from 2011 until 2015. During this period, the reports presented by IMCA were of the event-tree type, showing information regarding water depth, the configuration of the DP system and meteorological information. Before this period, the event trees lacked some of these data; and since 2015, the reports presented were just a sample and did not include all the incidents reported.

However, the reports collected can contribute to understanding the common patterns that can be found in the different incidents, thus finding an interpretation that could help improve the safety of these operations. Periods of downtime can mean a considerable amount of money loss. In some cases, the incident can lead to catastrophic consequences, leading to the loss of the ship and even pollution of the environment.

In this context, the research presented in this chapter aims to propose a mathematical model using logistic regression, which could help predict under which conditions an incident can occur. Furthermore, the condition of the incident can be determined beforehand, and as such, the likelihood of having an incident ending in an excursion can be modelled.

At the same time, and knowing that perhaps the human error is the easiest of all mistakes to correct, the model will be determined once again taking into account whether a human error was the cause of the incident or not, and the resulting models will be compared.
