Navigational Safety When Dredging in Heavily Trafficked International Waters
WODCON XXIII - Dredging is changing - The Practice. The Science. The Business.
H Brüske, F. Mølsted Rasmussen, C. Paulsen, C. Iversen
"The enduring vision of an immersed Tunnel to cross the 18 km wide Fehmarn Belt between Rødbyhavn and Puttgarden is now about to be realised. However, offshore construction activities are challenging because Fehmarn Belt, being the main entrance to the Baltic Sea, is one of the heaviest trafficked fairways in the world. This paper presents the Risk Control Measures taken to ensure that the commercial ship traffic can be conducted safe and efficient in Fehmarn Belt also during the Construction Phase: • Maritime coordination group • Vessel Traffic Service (VTS) • Guard vessels • Work vessel coordination • Marking of construction activities • Mobilisation and deployment of tugboat Furthermore, the paper will present the most important analyses conducted documenting that maritime safety can be maintained during the Construction Phase. These analyses comprise a quantified risk assessment and real-time simulations. A quantified risk assessment conducted to demonstrate that the combined effect of all implemented Risk Control Measures ensures that the current level of Navigational Safety is maintained throughout the construction phase. Real-time simulations have been performed to collect expert opinion by testing if the markings of the Work Area (i.e. buoyage and lights) are correctly interpreted under different visibility conditions and to simulate the most challenging construction scenarios. The real-time-simulations successfully showed that the tested risk reducing measures ensure effective and safe navigation during the Construction Phase. Finally, the paper will present the current status concerning Navigational Safety. Dredging of the Tunnel Trench started mid July 2021. The status concerning Navigational Safety is that we are learning from observations and incidents and following up on safety and efficiency in meetings with experts having practical knowledge of offshore operations and navigating ships in the Fehmarn Belt. The conclusion is that we have constant learning from observations and the general impression is that the ship traffic is conducted safe and efficient."
Keywords: Navigational Safety, quantified Risk Assessment, real-time simulations, Risk Control, Fehmarn Belt Tunnel