A grapple anchor device suspended underwater from an unmanned watercraft has
prongs
pivotally mounted on its tubular housing for hooked engagement with a tow line
extended from a retrieval ship so as to tow the watercraft underwater toward the
ship. A tow rod within the grapple anchor housing, connected by an anchor line
to the watercraft being towed, undergoes dampened axial displacement to condition
the grapple anchor device for automatic release of the prongs from the tow line
in response to a reduction in the towing force exerted through the tow line after
the watercraft is towed into position adjacent the retrieval ship and undergoes
crane lift up onto the retrieval ship by its shipboard crane so that the tow line
may be withdrawn while the watercraft is transferred onto the ship.
