The Ceres Paragon Terminal, which is reaching completion in the Dutch port of Amsterdam, is claimed to be the fastest container terminal in the world. What is unique about it is that one of its three berths is indented, especially designed for the latest generation of mega container ships. Ships sail into the indent and are worked by up to nine super-post-Panamax cranes on both sides of the vessel simultaneously. It is a simple concept, but apparently this has never been done before.

For flexibility, cranes on one side of the indented berth can travel round the corner to work the conventional quayside berths as required.

The cranes at Ceres Paragon, built by ZPMC of China at a cost of $2.5m each, are among the biggest and the fastest container cranes in the world. Each crane stands 112m high and has an outreach of 61m. Lift capacity is 65t under the spreader and 100t under the cargo beam. The gantry frame of the crane leans back 6m toward landside in order to clear the long boom from the other side of the slip. But they have other significant features too.

Collision avoidance

Operating cranes on both sides of the ship introduces the potential for collision of cranes and boxes over the ship. A double redundant safety system has been provided to prevent boom-to-boom and spreader-to-spreader collision.

Three levels of collision avoidance protection are provided:

• central computer control

• protection equipment on the crane

• crane operator intervention.

A central computer monitors the position and attitude of each crane and the crane system as a whole to prevent the operator or the automated control from allowing any crane to interfere with any other crane on the terminal.

Sensors on each crane determine the positions of gantry, boom, trolley, hoist, and flipper. These positions are fed to the central computer through fibre optic cable. The crane position is determined from dock-mounted transponders, magnetic reference points, and gantry wheel encoders.

Computer screens show the real-time position of each crane and the position or attitude of the boom, trolley, hoist, flippers and twist locks of each crane.

All slow-down and safety zones can be adjusted from the terminal with controlled access to the computer programmes.

A video screen in each operator’s cab shows the relative position of each adjacent crane. When on the indented berth, this information also includes the relative position of the cranes on the opposite side of the berth. The operator will be able to compare the data of onboard distance sensors with visual observation for backup collision avoidance and system verification.

To support current and future automation, the computer stores ship-loading plans and shows real-time loading and unloading of the ship, including weights and sizes of containers handled.

In case the central computer fails, each crane is equipped with a laser scanner that measures the distance between booms working the indented berth. The distance is displayed on the screen in the operator’s cab and an alert is sounded to all operators and central management if the booms get too close.

Behind the operator’s normal field of vision there is a common area of the indented berth and the adjacent quayside berth, at right angles to the indent, where the backreach of one crane could collide with another. In this blind spot the laser system is considered unreliable and so a corner protection system backs up the central computer. This system consists of magnets buried in the dock and three-way switches on the cranes. The crane switches are normally set to allow only the indented berth cranes to have access to the corner, but they can be switched so that either no crane has access to the corner, or only the quayside berth cranes have access to it.

The third level of collision avoidance is operator intervention. If an operator plans to raise his boom, he radios the operator facing him across the berth. Also, when the boom is fully raised, a green light is visible on the crane at all times, even when the crane is stowed and not operational. The light is hardwired to a boom-up limit switch.

If all of the above fails, there are gantry bumpers to absorb the impact of a collision.

Noise abatement

A significant element of the crane design was the need to meet noise abatement requirements so as to minimise the impact on a nearby residential area. The specification required that the equivalent sound power level of the crane shall not exceed 100dB(A) for simultaneous main hoist motion and trolley motion. This is equivalent to a noise pressure level of 55dB(A) at a distance of 60m from the centre of the crane trolley runway. A crane without any noise abatement treatment was measured at around 72dB(A) at 60m away for trolley travelling at full speed.

To minimise noise, polyurethane festoon trolley wheels were used and the machinery house was insulated with sound absorbing material.

The noise abatement requirement also resulted in the decision to use a rope-towed trolley instead of the initially specified machinery trolley. With the machinery trolley design, the biggest noise source is the trolley, either from the machinery inside it or from the trolley wheels rolling on the rail. Noise-absorbing panels and vibration-isolation pads would reduce the noise from the machinery inside the trolley. The weight of these materials, however, would significantly increase the trolley wheel load. The higher wheel load would then increase the rolling noise. Because of the complications involved in quietening the machinery trolley, ZPMC was more confident meeting the noise-abatement requirement with a rope-towed trolley design. After considering noise abatement requirements, productivity and maintenance, the owners and their engineer agreed with the crane builder’s proposal to use the rope-towed trolley.

With the rope-towed trolley design, however, there was concern that the rope would stretch and that catenary effect would reduce productivity. The catenary trolley is the typical solution for reducing the catenary effect. But even with the catenary trolley, the long runway will result in a big catenary effect. Intermittent rope supports spaced at about 25m are used to control the rope catenary. The advantages of the rope supports are improved productivity, and no catenary trolleys are needed. The disadvantages include a more complex reeving system, more sheaves, and potentially a shorter rope life.

Taking corners

The five cranes on the south side of the indented berth will also serve the quayside and so travel on curved rails. A gantry equaliser system articulation in conjunction with the curved rail geometry is designed to optimise the offset of each wheel with the rail. Main equaliser, sub equaliser and tracks at each of the four corners are designed to rotate relative to each other about the vertical axis.

During corner travel, the power cable is manually released from the cable guide. The cable reel is controlled from the crane at ground level. The cable is laid out, pulled to the corner and laid in the trench. A special cable with increased wear resistance is used, since it may be dragged on concrete pavement.

Operations are supported by 39 high-speed diesel-AC electric Nelcon straddle carriers with Siemens electronic controls. The 13m-high straddle carriers have a capacity of 50t and feature twin 20ft Stinis spreaders. They have a travel speed of up to 30km/h and are capable of lifting one over three containers. They feature rubber suspension and Kessler wet disc brakes fitted to the inner pair of wheels on each side. The straddle carriers are controlled and monitored by a yard management computer system with GPS.

The Ceres Paragon Terminal was scheduled to open in July 2001 but is now scheduled to begin operations early next year. On opening it will have an annual capacity of 600,000 containers (950,000 tonne equivalent units). The Amsterdam Port Authority has plans for a phase two development on a neighbouring 60ha plot, with a second indented berth. Ceres has an option on this development.