AWT Weather Routing/Routeing: Applied Weather Technology

Voyage Optimization Using AWT’s Onboard Voyage Planning System

By Dr. Thomas Weber

AWT provides a powerful voyage optimization function with its onboard voyage planning system, BonVoyage (BVS). With BVS, the Master can calculate the optimum track to follow from any point to any point along the route, taking into consideration the specific characteristics of the vessel and the forecast conditions ahead. The optimized route can then be compared with any number of alternatives, such as a route based on the Master’s experience.

The calculation behind the route optimization algorithm consists of a convergent combination strategy for determining the optimum route and, if required, speed as well as weighted penalties handle any undesired condition. BVS offers two objective functions, minimum voyage time and minimum fuel consumption.

The minimum time function provides the best arrival time based on a constant calm sea speed or RPM while minimum fuel consumption determines the optimum track and the required calm sea speed / RPM for on time arrival. Buffer times to account for unexpected speed losses can also be considered. AWT’s strategy is to provide a powerful optimization function in order to give the Master an objective evaluation of the voyage’s efficiency and safety on board.

Optimization which does not allow the Master to define the vessel operating thresholds is often not sufficient, e.g. certain weather thresholds which should be avoided along the optimized route. For this reason, AWT’s optimization takes into account weather induced constraints such as directional-wise maximum wave heights or wind speeds as well as ‘no go’ areas that are blocked for the purpose of optimization. This gives the Master close control and the ability to adjust the optimized route for the particular requirements of the voyage based on these constraints. Because the optimization function is fast and usually takes no more than a few seconds to run, the Master can vary the constraints during the practical voyage planning on board to study its effects on the route and hence on the costs of the voyage. This helps to develop a reasonable strategy which can be checked continuously during the voyage by re-optimizing the remaining part of the voyage when new weather data becomes available.

The benefit of optimization can be seen in efficient and safe routes. Optimization also assists the Master when evaluating any recommended route. Ultimately, with the regular use of BVS, Masters will become more aware of all the options available to them and thoroughly review their intentions against a number of reasonable options.

AWT will also customize the optimization function to the specific requirements of our clients, such as a new objective function for sail assisted vessels, variable speed profiles for minimum fuel consumption or added resistance and resonance avoidance as new constraints. The goal is to objectively determine an efficient and safe route which takes optimum ship routing to the next level.