This invention relates to anchors for providing a means for attaching a flexible line, cable or the like, and more particularly to an anchor which, when not in use, presents a top surface which is flush with the surface of the material in which it is mounted. 
Disappearing anchors which are embedded in material such as the ground or concrete are known in the art.  One known anchor comprises an outer cylindrical housing which is provided with a series of vertical serrations on the outer surface thereof.  The serrations present an irregular surface for increasing the frictional force between the housing and the material in which the anchor is embedded. 
However, if the material in which the anchor is to be embedded is, for example, a wooden deck (such as would surround a swimming pool, the anchor being used to secure a pool cover over the pool when not in use), the outer surface serrations of this known anchor would not be sufficient to maintain the anchor securely within the wooden deck.