Active Pendulation Control (APC) for cargo cranes
Cargo positioning can easily account for as much as 40 percent of the total crane cycle time, so anything that helps to reduce this can therefore yield a large gain in productivity. MacGregor believes that cargo handling aids improve discharge times and the safety of crew and cargo and can benefit numerous operations, including the installation of offshore wind turbines and other offshore heavy load handling operations.
One of our unique cargo handling aids, active pendulation control (APC), cancels out swing motions when cranes are transferring cargo between moving or stationary objects.
MacGregor recognises that challenging load handling situations exist in the open sea, in high sea states, when both the discharging and the receiving vessels are moving.
Sometimes having a skilled crane operator is not enough to cope with them; these conditions can endanger the safety of employees and cargo.
Also, as ships increase in size, larger vessels may frequently be unable to get into convenient ports. Therefore, transloading at sea will become increasingly necessary and may not even be possible without anti-pendulation assistance for some bulkers or container ships.
Smooth, safe lifting operations
The MacGregor APC system uses a set of motion sensors to detect and prevent pendulation induced by sea motion and wind. It also has the ability to compensate for ship motions in other vessels during ship-to-ship cargo transfer. This is achieved by placing sensors on the target vessel. The system then uses motion data from both vessels to make cargo landing and lifting operations as smooth and safe as possible.
APC is especially useful on bulkers for less experienced drivers who could benefit from greater precision and faster positioning of the grab above the hoppers. Minimised pendulation of the grab can also increase overall operational speed and reduce stress in bearings, wires and sheaves. At an unprotected harbour, where waves can cause significant vessel movement, APC also helps the crane operator reduce pendulation.
A gyroscope installed in the hook block communicates wirelessly with the crane control system. The wireless communication reduces the need for cables that are exposed to wear and tear and that can cause downtime for repairs. All the maintenance required is a battery change between shifts.
All MacGregor crane designs are based on our lengthy experience and backed-up by unrivalled global service support and a proven track record of more than 13,000 crane deliveries worldwide over the past 50 years.
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