Introduction
What would be the impact on the container terminal industry, if containers were equipped with integrated twistlocks? A cost efficiency analysis demonstrates the significant cost savings to the industry and highlights safety, productivity and sustainability benefits.
For a long time, the handling of twistlocks (or cones) and semiautomated twistlocks (SATL’s) has been a heavy burden for the container industry. The burden consists of the operational cost to place and remove these cones in every step of the container supply chain (on the vessel, on road trucks and on trains). Moreover, the handling (coning and deconing) typically takes place in areas where dense traffic takes place, such as the apron of a container terminal, or where inherently unsafe situations take place, such as the hold of the vessel, or close to moving containers. It is therefore often a source of injuries or casualties.
The introduction of the SATL has already removed the locking and unlocking of the cones on the vessels, but still requires the manual placement and removal of the cones, and as such only addresses some of the costs, and does not address the safety issues.
Automated twistlock handling stations
There have been many efforts in developing automated twistlock handling stations (see Port Technology International editions 50-58), which could carry out this placement and removal of the twistlocks. Although various tests have been carried out, it has not led to a large-scale application. Here, various reasons can be identified, both technical and economical. To mention a few:
- Not all types of twistlocks can be handled
- When the twistlock station gets jammed, it is blocking a large area under the QC
- Ideally, the station is placed on a sill beam rather than on the ground. However, this adds a significant weight to the QC, which may have impact on the crane rail, and possibly reduces crane lifting capability
- The stations still have to be supplied with sufficient twistlocks
- The stations needs to be replaced every time the QC moves, even when it moves only half a meter the station is not positioned correctly
- The stations are not easily applicable to on-dock and inland rail environments
- The stations require skilled labor for maintenance
- The stations will reduce productivity in bombcart environments
- The investment required for a single station is quite high (more than $1 million), leading to a quite long return on investment
Universal Container Locking System: how it works
Another development, and the focal point of this paper, is the Universal Container Locking System (UCLS), a system that is fitted into the corner castings of a container, and fulfills the container locking and unlocking without the need to place or remove it every time a container gets handled.
The UCLS was devised on the premise that the container shipping industry needs a single, safe, easily adaptable and truly automated system for securing containers during transport across the entire container supply chain. It is designed to improve safety, productivity, environmental sustainability and profitability for shipping companies, railroads and terminal operators.
The UCLS is in the final stages of development and early stages of field testing with RMG cranes, straddle carriers, top picks and side picks are promising. The safety and economic opportunities are compelling and worthy of serious consideration by the maritime community (shipping lines and terminal operators), railroads and trucking community.
The first image in Figure 2 shows a UCLS locking unit mounted in the lower corner fitting of a standard ISO container. A UCLS actuating unit is housed in the upper corner fittings of containers as shown in the second image of Figure 1. Simple, rugged linkage connects the actuating and locking units. The linkage is protected by existing container structure and does not reduce the cargo carrying capacity of the container. When the twistlock of a hoisting spreader locks to the container to hoist it, the twistlock engages the UCLS actuating unit which in turn causes the UCLS locking unit to rotate to the unlocked position.
The container can then be hoisted clear from its base as shown in the third image of Figure 2. When the spreader twistlock unlocks from the container, the UCLS locking unit, returns to its natural, fully locked position. When a conventional twistlock (SATL or fully automatic twistlock) engages the upper corner fitting of a UCLS equipped container, the UCLS locking unit remains in its fully locked position allowing conventional containers to be stacked on UCLS containers onboard ships and in container yards exactly as they would on any other container. Other common container securing equipment such as lashing rods or bridge fittings etc. do not interfere with UCLS components.
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