Hydraulic telescopic knuckle boom marine deck crane for port and ship The crane is controlled from an open platform above the slewing ring. One motions each (hoisting ,slewing or luffing) can be done with full load.Each hydraulic circuit is provided with equipment for limiting hydraulic pressure to preset values corresponding with crane capacity. The crane is provided with an automatic hook stop in top position.Over load safety device.Luffing up- down. The luffing cylinder is designed for safe buffering in extreme positions. Shanghai Bangding Machinery Equipment Co.,Ltd.