Offshore Operational Advisory System
Acta Marine is involved in the Offshore Operational Advisory System OOAS joint industry project. This project aims to improve the efficiency of offshore wind farm installation and maintenance vessels, by using better data for planning and executing operations. For a typical vessel it is expected that this method will result in tens of additional working days per year. A consortium including Acta Marine, MO4, Next Ocean, Radac and SMST was formed and is led by MARIN. The OOAS project will run from Q4 2020 until the end of 2022.
Background and motivation
The operability of offshore wind farm installation and maintenance vessels strongly depends on weather conditions. Winds, waves and currents impact the ability of a vessel to keep station. High motions in waves can lead up to dangerous situations for the crew or jeopardizing integrity of equipment. For example, walk-to-work vessels need to operate closely to wind turbines and connect with a gangway for personnel to access the turbine. These ships cannot drift too far away from a turbine or the connection will be lost.
Furthermore, the gangway has a limited capacity to compensate motions. Just as in many other offshore operations, operational limits are used to guarantee that operations are executed under safe conditions.
The project delivers a system which gives planning advice in several stages of operation, from heading and routing advice on board to workability planning one year prior to operation. The system provides advice based on a generic hydrodynamic approach, which is able to take into account the non-linear behaviour of the DP system, anti-roll tank, gangway characteristics and complex environmental conditions. Measured 2D wave spectra from the vessel and measured ship motions are used to continuously update and improve the hydrodynamic calculations and wave monitoring algorithms to deliver unprecedented accuracy in terms of operational advice. The planning methodology is not limited to walk-to-work vessels and can be used for many other operations taking place in critical environmental conditions. The method has the potential to increase a vessel’s uptime by many days per year, without investing in costly hardware and by merely adopting a smarter way of working.