The challenges Challenges encountered include delays to inbound vessels - if berths are not immediately available - since ships waiting to berth need access to a suitable anchorage away from major transit routes with protection from rough weather. Increased risk potential, coupled with the ever more risk intolerant and litigious society that we live in, means that planning and risk mitigation has taken on a whole new importance. Additionally, the issue of safe vessel movement often extends beyond the port’s immediate jurisdiction but must still be addressed in order to protect people, the environment and the business bottom line.

In busy port and coastal areas such as the English Channel, Hong Kong and Singapore, where international and local shipping lanes converge, vessels frequently pass or cross other ships in close proximity

during their navigation to and from port approaches. In some congested areas crossings result in multiple encounters, in which the crossing ship may have to take avoiding action to pass a series of vessels safely.

The evolution of modelling Marine traffic simulation models have grown in sophistication in recent years in order to assess the impacts of future developments on safety and the consequences from port developments and increases in traffic streams. While earlier models have provided insights into marine risk, the increasingly overcrowded port areas around the world have highlighted a number of limitations. For example, in congested waters ships avoid collision by observing a set of steering rules, reducing speed or stopping, and following defined traffic routes. Conventional marine traffic

models have only reproduced the last of these items. A need has existed for a model which incorporates the wider range of real-life navigation behaviour responsible for collisions, in particular one suited to the extremely congested waters often seen in Asian ports.

As part of its portfolio of port-planning software, BMT has deployed its DYnamic MarIne TRaffIc simulator, DYMITRI, specifically to meet the challenge posed by the assessment of collision risk of dense marine traffic streams. DYMITRI has now been used for more than a decade to model marine traffic and evaluate collision risk in Korea, Singapore and Hong Kong, and benefited from extensive collaboration and validation. Major infrastructure developments examined include the construction of new terminals, reclamations and bridges.

DYMITRI, BMT’s traffic simulation tool provides comprehensive information on vessel traffic density, here illustrated through colour contours.