3. Control system

For the vessel train to operate control software is needed that communicates between the ships in the train and controls the navigation of the follower vessels. Control software has been developed which is supported by accurate and up to date water depth information needed to determine safe passage of the complete train. Hydrodynamic studies have been done to investigate the hydrodynamic interactions between the vessels in the train. The vessel train concept was demonstrated on the bridge simulator to have captains gain experience with the concept, at model scale to test the control system and at full scale to demonstrate the vessel train in controlled real conditions (more information in Document A [D3.1]). 

Ships sailing on the river continuously measure the water depth. CoVadem has developed a system to integrate all individual depth measurements to create an accurate water depth chart, including models for water depth prediction, see document B. These charts and predictions are used by the VT operator when composing the vessel train to assure the complete train can pass over the shallow water and under the bridges along the route. 

Vessels sailing in close vicinity will interact each other’s behaviour such as the resistance and manoeuvring capacity. A study has been done to determine the hydrodynamic interaction between vessels in the vessel train at varying distances. It appeared that at the distances between the vessels which are operationally acceptable the interaction is negligible, see document C. Manoeuvring coefficients of typical ships were determined to be included in the control software to better control the follower vessels. 

Argonics and Innovative Navigation have together developed to Vessel Train control software, see document D. The control system will control the follower vessels from the leader vessel and includes safe communication between the vessels. Follower vessels follow the track defined by the leader vessel at a mutual distance imposed by the leader vessel. Solutions have been found to navigate around static and dynamic objects on the river. Operation without personnel on the bridge in most cases. Some cases such as bad weather or heavy traffic require personnel monitoring the navigation from the FV bridge. These situations can be foreseen, and crew can be alerted in time. 

The vessel train concept was demonstrated on a full mission bridge simulator, at model scale and at full scale, see documents E and F. The bridge simulator demonstration was done to demonstrate to captains how a vessel train is controlled from the leader vessel and to test how captains cope with the role of VT leader. The movie in document G shows the setup and experience with the VT. Model scale tests were done at DST as shown in document H where the control system was tested in a controlled environment. Finally, the vessel train was demonstrated at full scale with a cargo vessel (M/V Oxford) as leader vessel and a passenger vessel (M/S Viva Moments) as follower vessel documented in document F. These tests showed that the vessel train is technically feasible and identified some points for improvement such as improvement of the stopping procedure, control algorithm needs to be adjusted to limit the rate of turn and crossing of vessels through the vessel train should not be allowed. 

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