Abstract: A crane has a generally horizontally disposed main boom arm centrally pivotally mounted on a turret supported for rotation atop a central column. The main boom arm supports a load at one end and a counterweight at its other end. The main boom arm load support end has a depending vertical arm, linked in parallelogram fashion with the turret, and with a lower rotatable load carrying swing arm movable through a full 360.degree. arc without interference with the column and turret. The column may be mounted on a dolly. A rack and worm pinion arrangement are provided on either the main boom or the counterweight for adjusting the distance of the counterweight from the column and turret, thus to balance the crane in a vertical plane.