Diversification of Common Tools for Container Lifting

In cargo transportation, container terminals are equipped with container lifting equipment to handle containers efficiently. Based on operational experience from container ports worldwide, a typical scenario is that many underground container storage areas are equipped with one to three container lifting units. When selecting and configuring container lifting systems, several key performance parameters must be considered.

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1. Outreach (Horizontal Reach)

Outreach refers to the maximum horizontal distance from the axis of the quay-side sliding rail to the vertical axis of the container handling spreader. The required outreach depends primarily on the width of the vessel berthed at the port and must also account for the maximum allowable stacking height on the main deck. Even when a vessel lists or tilts outward, the container lifting system must still be able to lift containers located at the top and outermost positions of the main deck.

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2. Lifting Capacity

The lifting capacity of a container lifting system is calculated as the rated lifting capacity plus the total weight of the handling equipment (spreader). Since spreaders come in various types and weights, and operational standards differ across ports, the lifting capacities of container lifting systems vary worldwide.

When determining the lifting capacity, the following factors are usually considered:

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3. Maximum Lifting of Hatch Covers

When handling the hatch covers of container ships, the total weight of an individual cover typically does not exceed 28 tons. For non-standard or non-international containers, alternative methods may be used, such as simultaneously lifting two 20ft containers, whose combined weight generally reaches approximately 40.6 tons.

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4. Inner Reach (Inreach) for Oversized Cargo

The inner reach refers to the maximum horizontal distance from the inner sliding rail axis of the container lifting system to the vertical axis of the spreader. When determining the inreach, two main considerations are addressed:

1. Whether containers can be placed properly inside the hold.
2. Whether hatch covers or other deck equipment can be accommodated during lifting operations.

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5. Lifting Height

The lifting height of a container lifting system consists of two parts:

• The height above the sliding rails
• The height below the sliding rails

Lifting height is influenced by several factors: container dimensions, waterline, tidal range, the number of stacked containers on the main deck, the absolute port elevation, and potential vessel tilt.

Currently, most quay-based container lifting systems designed and manufactured worldwide are configured with a lifting height of approximately 25 meters above the rails and 12 meters below the rails.