The development of offshore wind energy has led to the emergence of entirely new types of vessels: self-elevating vessels or vessels for servicing and constructing offshore installations. However, Dutch shipbuilders decided to combine several functions on one platform, creating another class of vessels.
In 2017, the Dutch company Vroon Offshore Services acquired two vessels, VOS Start and VOS Stone, of the Walk-to-Work type. It was the establishment of coastal wind farms, consisting of several dozen individual platforms, that pushed shipbuilders to develop vessels of this class that require seamless, repeated visits to each platform and support for extended maritime operations.
The support vessel Walk-to-Work-class service vessels are designed to provide safe access from the ship to offshore structures or other objects at sea. These vessels are commonly used for servicing offshore installations such as wind turbines or oil platforms by transporting personnel or equipment to the work site. Typically, vessels of this type are equipped with gangways with active wave compensation.
The VOS Start and VOS Stone vessels were laid down at the Fujian Southeast shipyard in China and then completed at the Damen Oranjewerf facility in Amsterdam in 2017.
Modern vessels have a length of 80 meters, a width of 18.4 meters, and a draft of 7.8 meters. The power plant provides a vessel speed of 13 knots. The crew of the vessel consists of 27 people. On the 260-square-meter working deck, there is a crane with a lifting capacity of up to 50 tons and a gangway with an active compensation system to reduce vertical oscillations caused by sea waves. Additionally, state-of-the-art vessels offer accommodation for multiple workgroups of up to 60 people, including engineers, managers, and project leaders, providing them with both office and workspace. They have at their disposal a workshop with necessary machinery, a warehouse with tools and spare parts, as well as a workshop with a 3D printer for performing ongoing repairs.
The most important detail on Walk-to-Work vessels is the motion-compensated gangway to reduce vertical oscillations from waves up to 3 meters high. It is installed on a height-adjustable column, which keeps the gangway in a horizontal position, and an internal passenger lift provides transportation of workers to the required height. This system is operated by just one operator, as it is equipped with extremely fast sensors and control mechanisms.
Upon returning to the vessel after a day of work, workers and engineers can relax in the cinema, spend time in their cabins, or engage in sports in the gym. Onboard, all hotel-like comforts are provided.