Hydrautrans is developing a hybrid mechanical-hydraulic drive train for 13+ MW offshore wind turbines. The hybrid drive train has a modular design and is currently designed with a capacity of 13MW and can be up scaled to higher capacities.The Hydrautrans Drive Train (HDT) makes use of the patented Floating Cup Technology of INNAS. Hydrautrans and INNAS performed the cup and piston test, in collaboration with TNO and VDL ETG precision. The cup and piston tests were conducted to ensure the manufacturability of the cup and plunger for the HDT and validated the use and efficiency of the Floating Cup Technology in the HDT. The results, reported by Hydrautrans, of the tests showed an efficiency of around 99% and the absence of wear and tear. Further VDL achieved a very high precision in the manufacturing process. The measurements carried out by INNAS also showed low resistance. The hydraulic components have a high-power density which enables a compacter and lighter drive train compared direct drive turbines. The company is now looking for a wind turbine manufacturer to implement the HDT technology.