Improving Group Transit Schemes to Minimize Negative Effects of Maritime Piracy

Contemporary maritime piracy around the Horn of Africa presents a serious threat to the global shipping industry. A number of countermeasures were deployed to minimize the probability of a successful ship hijack, one of them being the establishment of the International Recommended Transit Corridor (IRTC). Currently, all ships transiting the Gulf of Aden are recommended to follow the IRTC and take part in group transit schemes (GTSs)-prescribed fixed schedules stating a time of arrival to the beginning of the corridor and a speed at which to sail through the corridor. We provide a number of contributions that improve the GTS: we formalize the grouping problem, we design an efficient algorithm able to compute optimal fixed GTSs with respect to the distribution of ships´ speeds, we provide a real-world data set with speeds of ships transiting the IRTC, and we compare the optimal fixed schedules with the currently deployed schedule and quantify possible savings. Additionally, we propose on-demand GTSs-customized schedules for a group of arriving ships-that take into account speeds, risk aversion, and actual positions of arriving ships. We formulate the problem of the optimal on-demand grouping as a biobjective mixed integer program, and we compute a set of Pareto optimal solutions. We evaluate the scalability of the approach, the structure of the solution, and quantify an improvement over the current GTS with respect to the number of ships grouped and the time saved.