The Mirabella V is with a length of 75 m and a mast height of 90m the currently biggest single mast sailing ship in the world. To allow the ship to enter in smaller harbours a hydraulic cylinder can lift up the 150 t heavy retractable keel by approximately 6.000 mm.

Because the hydraulic cylinder is always sub-merged or in the splash zone the Ultraplate rod coating was selected to provide a long life corrosion protection.

To put the weight as deep as possible in the keel, the cylinder is installed with rod side up. Therefore the hydraulic oil is feeded through the rod in the cylinder.