Successful Debut on Offshore Access Market for SafeWay
Van Aalst can look back on a very successful debut in the North Sea wind sector with the implementation of the SafeWay motion compensated offshore access system. The 28m-long walk-to-work Seagull-type gangway is able to compensate for significant wave heights of up to 3.5m on a standard 75m-long PSV hull, resulting in an operating window that can be significantly higher than other available systems in the market.
This first SafeWay gangway is currently installed on the OCV ‘Olympic Intervention IV’, owned by Olympic Subsea. The DP2 vessel is chartered by the German wind turbine manufacturer Adwen for maintenance activities and trouble shooting at three different wind parks located in the German sector of the North Sea. Under sometimes challenging weather conditions, with significant wave heights above 2.8 m, 851 people transfers were carried out during 173 landings without any problem in 29 days, including an additional 301 cargo transfers. The gangway incorporates a 3D compensated crane capability, for which the design includes a separate winch to transfer up to 400 (or optional 1,000) kilos. This efficient transfer of equipment helps expedite the operational workflow as well.
The Bureau Veritas approved SafeWay motion compensated gangway system incorporates three main features:
- Roll compensation: the SafeWay technology is based on a roll cylinder, enabling the system to keep the mast in a vertical position at all times.
- Height adjustment: the possibility of a stepless 10m vertical height adjustment enables the access arm to maintain a nearly horizontal position in all tidal conditions. This rules out unsafe uphill or downhill walking, further enhancing safety.
- Zero Impact Bumpering: active free floating, allowing maximum freedom in vessel heading and zero preparation at the landing point.
Adwen used the SafeWay access system for the first time during the maintenance campaign at the Trianel Windpark Borkum, where 40 turbines had to be inspected. After this project the ‘Olympic Intervention IV’ was directed to the Wikinger wind park, 35 km off the German Island of Rügen and Germany’s first offshore wind farm Alpha Ventus, located 45 km off the coast of Borkum.
Morten Endre Stakvik, Captain of the Olympic Intervention IV says: “I had never worked before with a walk-to-work system that can be lifted vertically and my experience is quite positive. This gangway is behaving perfectly and it was amazing to witness the speed of the personal transfers as well as the cargo transfers. The cooperation with the SafeWay operators is great. What I understand from the maintenance technicians it feels quite natural and comfortable walking 20m above sea level from our accommodation vessel to the structure. From the vessel you can walk straight to work in a totally covered construction. Just like walking in a jet bridge to a plane.”