The present disclosure is directed to an anchoring device for retaining a boat on a trailer or on top of an automobile either directly on the top or secured to a previously installed car top carrier. The device consists of a plurality of units each of which has a trailer or car top securing means and a boat securing means connected by a turnbuckle means therebetween to control the tension. The structure of the present disclosure permits the boat to be transported in either the upright or inverted position.