Loading/unloading crane with buoyant counterweight system

Claim 1

A loading/unloading crane assembly for transfer of cargo from a loaded first floating vessel to a second floating vessel, the crane assembly comprising: a floating crane barge; a column assembly extending vertically from the crane barge, the column assembly including a top portion, and a base; a horizontal boom, connected at an intermediate point thereof to the column assembly between the top portion and the base, and having opposite outer extremities on either side of the column assembly; means securing the boom to the top portion of the column at longitudinally spaced locations; a floating counterweight barge secured to the boom adjacent one outer extremity thereof by a first cable of fixed length; the first loaded vessel being located between the crane barge and the counterweight barge; a second cable of adjustable length securing the opposite outer extremity of the boom to the second vessel; and movable trolley means on the boom, including a vertically movable hoist cable with cargo engagement means, for withdrawal of cargo from the loaded first vessel, movement through said intermediate point, and placement of the cargo in the second vessel, the cable of adjustable length being lengthened as the second vessel takes on cargo.