Mooring
A mooring is a device with to a boat can attach so that it can remain in the same position.
A mooring is typically a heavy object located on the sea bed with a rope or cable going to the surface where a float makes it possible to pick it up from a boat.
Example: On the Great Barrier Reef a vast number of public moorings is set out in popular areas where boats can moor. This is to avoid the massive damage anchoring in the same spot would have done.
A crude illustration of a mooring: A concrete block on the sea bed, a rope going to the surface and a float. A boat is attached to the mooring.