Dutch maritime research institute Marin has tested three barriers aimed at averting collisions between ships and wind turbines. The research was prompted by the incident involving the Julietta D on 31 January this year. This drifting bulk carrier initially collided with a tanker before hitting a transformer platform and a turbine foundation for the Hollandse Kust Zuid windfarm currently under construction.A collision with an installed wind turbine carries a real risk of the turbine toppling onto the vessel, seriously endangering crew, passengers, the ship itself and the environment.
A group of 20 experts from Marin and the wider maritime sector developed three concepts for maritime crash barriers between shipping routes and offshore wind farms. The first concept involves a string of surface buoys secured by drag anchors. The second concept comprises a smart suspension net between fixed poles and the third is an anchored underwater hook line designed to catch the anchor of the drifting vessel. MARIN built scale models of all three solutions and ran tests in its Offshore Basin to see if the barriers were capable of deflecting a scale model comparable to the Julietta D in storm conditions.
The first results are promising. The researchers have established that all three concepts are able to intercept the vessel. The drag anchors of the buoy string dissipate the drift energy evenly, so that the vessel stays afloat across the waves. The anchored underwater hook heads the vessel into the waves, so reducing roll. That means the vessel remains in place while being exposed to relatively low forces. The smart suspension net initially showed too much droop, but with a bit of fine-tuning they were able to get this functioning too. Over the coming months Marin will go on to assess the various pros and cons of these systems.
Representatives of the following Dutch maritime and offshore organizations were involved in this project: Bluewater Energy Services, Mooreast, Vuyk Engineering, Heerema Marine Contractors, Boskalis, GustoMSC, KRVE (Rotterdam Boatmen), Pinkster Marine Hydrodynamics, Huisman Equipment, Orca Offshore en SBM Offshore.
