De Ryck, who takes up the new role on March 31, replaces current CEO Ivan Brems who is retiring from active executive duties to take on a consultancy role with the company.
Hansen's majority shareholder is Suzlon with 26%. De Ryck's promotion is the second time this week a senior appointment has been made within one of its off-shoots. On Tuesday the company announced it had poached Siemens Wind Power CEO Andreas Nauen to hold the same role at REpower.
The move follows the announcement of disappointing third quarter results by Hansen. A glut of turbines in the global market appears to have hit gearbox maker Hansen. The Belgian company reported a 12% fall in earnings compared to the same quarter last year.
De Ryck said: "Although these are clearly challenging times for the wind industry we are well prepared and have an outstanding team in place. Trading for the current financial year remains in line with previous guidance and as anticipated in January we have recently created additional financial flexibility for the Group by re-negotiating our bank covenants.
"I am convinced that Hansen is well placed to exploit the opportunities that lie ahead and look forward to leading the company to future successes."
Speaking about Brems decision to step down, Suzlon chief executive and Hansen chairman Tulsi Tanti said: "Ivan Brems has been instrumental, over many years, to the successful growth of Hansen into a world-leading supplier of high quality gearboxes for the wind industry.
Hansen is in the process of recruiting a new CFO.