SubscribeA modern, safe approach for unlashing containers on deck.
A tale of long poles
Unlashing the containers above deck on containerships is an essential, challenging part of routine vessel operations. When self-locking cones are used to secure the corner castings of on-deck containers to each other, the challenge increases dramatically with each vertical tier of containers, especially when poles are used to unlock the cones. Figure 1 shows a typical self-locking cone between two tiers of containers.
Poles used by lashing personnel standing on deck become unwieldy when attempting to reach and unlock cones above the fourth tier of containers, when pole lengths approach 25 feet and longer. Inclement weather with wind gusts, rain etc. makes this routine work even more difficult and dangerous, as does working aloft atop the container stack, using poles facing down.
Two cages from freedom
There is now a much better, safer solution for unlashing the top tiers of containers on deck: the Telescopic Personnel Cage (TPC) by Sort & Store.
As shown in Figures 2 and 3, the TPC is a self-contained, vertically and horizontally-telescopic device with a safety cage at both ends, each of which accommodates and protects a lasher.
The TPC has sockets at each corner of its top frame which mate with shore crane spreader twistlocks, allowing the TPC to be hoisted, lowered and telescoped from 20 to 45 by the crane spreader.
The cages at each end are designed to fit between the on deck container stacks on most containerships, allowing the lasher in each cage direct contact with the cones between the container tiers. Vertical positioning of each cage is accomplished by a self-contained, unpowered hydraulic system above each cage, controlled by a manual valve inside each cage.
A smooth transition
Thus, to unlock the top two tiers of containers on deck, the TPC, with lashers aboard, is hoisted above the top tier of containers in a stack and trolleyed to a position approximately centered on the top inboard container.
Each lasher then smoothly lowers his cage using the manual hydraulic valve, positioning each cage so that the lashing cones can be reached above the railings at the open ends of each cage.
Both lashers then unlock the cones, notify the crane operator by radio when done, and the TPC is then trolleyed to the next outbound position across the top tier to repeat the process.
When all cones between the top tier and next lower tier of containers have been unlocked, each lasher lowers his cage to the cone level between the second and third tier of containers from the top, and the unlocking process continues in reverse, from outboard to inboard.
The crane operator then lowers the the TPC to the dock, retracting the extended frames above each cage, and recharging both hydraulic systems.
The TPC can then be hoisted to an adjacent stack to repeat the unlashing process, or the lashers can exit the cages, and the TPC can be placed into storage, awaiting its next assignment.
A maintenance bonus
The TPC also provides a safe, efficient means of attending to frozen or damaged cones by positioning maintenance technicians with tools, oxy-acetylene torch etc. right in front of the problem cone(s). This is much quicker and safer than using ladders or going aloft.
Summary
The TPC is a safe, efficient, cost-effective tool for unlashing and maintenance procedures associated with on-deck containers. It is performing well at a major US East Coast Port, and at other locations.