NOVELTY - The device (100) has gripping structures (130, 130') for gripping impact shield pipes (210, 210') of a wind power plant (200). Gripping arms (132, 132', 133, 133') are attached to frame parts (131, 131') in a turnable manner and turned against the impact shield pipes, so that the impact shield pipes are pressed between the gripping arms. Rollers (136, 136') of the gripping structures are placed against the impact shield pipes. The gripping structures comprise hydraulic cylinders (134, 134', 135, 135') for turning one of the gripping arms.    USE - Mooring device for short-term mooring and long-term mooring of a vessel (claimed) such as boat e.g. trimaran, and ship to a wind power plant at rough sea. Can also be used for mooring impact shield pipe of structures e.g. oil rigs and production platforms, at sea.    ADVANTAGE - The impact shield pipe is attached at a bottom end of a mast of the wind power plant so as to prevent the vessel from hitting the mast of the wind power plant, thus protecting the wind power plant from damage. The mooring device is allowed to move along the impact shield pipes to a suitable height, when the device is used to grip, so that the device can move in a direction of a longitudinal axis of the impact shield pipes, where the force directed at the vessel and generated by the waves is small. The device can easily be changed if the conditions in the sea area change, and the device can be utilized even in a significant wave height of three meters and can easily moor the vessel with use of the impact shield pipes at the suitable height.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for mooring a vessel.    DESCRIPTION OF DRAWING(S) - The drawing shows a top view of a mooring device.    Mooring device (100)    Gripping structures (130, 130')    Frame parts (131, 131')    Gripping arms (132, 132', 133, 133')    Hydraulic cylinders (134, 134', 135, 135')    Rollers (136, 136')    Wind power plant (200)    Gripping impact shield pipes (210, 210')