Marine tether anchoring device

A marine tether anchoring device for use with an anchoring chamber having a neck portion, comprising a tether provided with a hollow segmented first spring collet adapted to be inserted into the neck portion of said chamber, said first collet having adjacent its extreme end an inner enlarged cavity, an intermediate section of diminishing width between said cavity and a hollow passage through said first collet, a locking plug extending along said hollow passage and having an end of increased width arranged to be located in said enlarged cavity in a first position, and means for moving said plug between said first position and a second position when said plug engages the intermediate section to open out said first collet and provide a securing of said first collet in the anchoring chamber, said anchoring device further comprising a first slideable sleeve in the neck portion of the anchoring chamber, said first sleeve having a second spring collet, provided with a load ring at its lower end, and which can be expanded to be securely engaged in an uppermost position in said anchoring chamber when tension is applied to the tether, and a second slideable sleeve within said first sleeve and surrounding said hollow segmented first spring collet, said second sleeve extending to a locking ring arranged to engage between said load ring and outer parts of said intermediate section, in which said load ring can be forced outwards to release said locking ring when said first slideable sleeve is in a lowermost position.