Generally, deck cranes of this type use the "Toplis' three-part reeving system for the hoist rope and the luffing ropes are rove between the jib head and the superstructure apex which gives them an approximately constant load, irrespective of the jib radius. This load depends only on the weight of the jib, the resultant of loads in the hoisting rope due to the load on the hook passes through the jib to the jib foot pin (Figure 3 a). If the crane is inclined 5° in the forward direction due to heel of the ship the level luffing geometry is disturbed and the hook load produces a considerable moment on the jib which increases the pull on the luffing rope (Figure 3 b).

In the case of a 55 tonne crane the pull under these conditions is approximately doubled and the luffing ropes need to be over-proportioned to meet the required factor of safety. If the inclination is in the inward direction and the jib is near minimum radius, there is a danger that its weight moment will not be sufficient to prevent it from luffing up under the action of the hoisting rope resultant. Swinging of the hook will produce similar effects to inclination of the crane.

In the Stothert & Pitt 'Stevedore' electro-hydraulic crane the jib is luffed by one or two hydraulic rams. Pilot operated leak valves in the rams ensure that the jib is supported in the event of hydraulic pressure being lost and an automatic limiting device is incorporated which ensures that maximum radius cannot be exceeded. When the jib is to be stowed the operator can override the limiting device. In the horizontal stowed position the cylinder rods are fully retracted into the rams where they are protected from the weather.

Some cranes are mounted in pairs on a common platform which can be rotated through 360 deg. The cranes can be operated independently or locked together and operated as a twin-jib crane of double capacity, usually to give capacities of up to 50 tonnes.