Military


Lift-on/Lift-off (LO/LO) Ships

LoLo vessels (Lift on - Lift Off) vessels can transport a range of different products as a result of their flexible cargo space, container capacity and onboard cranes. Lift-on/Lift-off (lo/lo) cargo is containerized cargo that must be lifted on and off vessels and other vehicles using handling equipment. A LOLO operation is when cargo is loaded and discharged over the top of the vessel using cranes or derricks. LoLo vessels load and unload cargo at Roll On-Roll Off (Ro-Ro) ports, Load On-Load Off (Lo-Lo) ports and at unserviced jetties, using its own cranes. Self-geared Lift-on/Lift-off (Lo/Lo) type vessels are loaded and unloaded by a crane, which lifts cargo to a specific location on the Lo/Lo ship. The cargo is loaded pursuant to a specific plan that is necessary in order to balance the Lo/Lo ships as they are not equipped with ballast-adjusting mechanisms.

Although roll on-roll off (ro-ro) vessels offer significant per container cost benefits in terms of handling and types of labor used, the reduced carrying capacity of these vessels may favor the use of lift on-lift off (lo-lo) container-on-barge for general cargo services (containers can be stacked multiple containers high).

Port and terminal operations at deepwater seaports are also not amenable to shortsea shipping operations. Since ocean-going containerships are the primary customers of these ports, they typically have preference when it comes to berth, labor, and equipment availability. This is a particular concern for lift-on/lift-of (lo-lo) ships, which require a significant amount of labor and equipment for loading and off-loading of cargo. In fact, coastal lo-lo ships typically have to allocate 24 hours per port call, though only eight to 12 hours are required for on-load and offload of cargo.

Cargo vessels can be equipped with a variety of cargo handling systems, the most commonly encountered systems being classified as either lo-lo or ro-ro (the vessels may sometimes be referred to as lo-lo or ro-ro vessels even though it is possible to have both loading capabilities on the same vessel). Each vessel type and cargo handling system has applications that may be more appropriate for specific commodities. In addition, each has advantages and disadvantages in terms of cost and service characteristics. Matching the technology to available port infrastructure, commodity markets, and labor constraints will have a strong influence on the economics of a particular operation.

In the 1960's and early 1970's, conventional vehicle carriers of the Lift On Lift Off (LOLO) type were used extensively in connection with the transportation of factory new cars. The vessels would rig hoistable car decks and load anything from 500 up to 3000 cars depending on the size of the vessel. The LOLO was soon replaced by the Roll On Roll Off (RoRo) car carrier. As the 70's developed, the Pure Car Carrier (PCC) started to replace the conventional vessels. The PCC was then developed into the Pure Car Truck Carrier (PCTC) in order to meet the demands for high and heavy cargo.

Lift-on/lift-off (lo-lo) cargo handling systems are often used on vessels or barges used to transport containers in shortsea operations. Some lo-lo vessels, referred to as "self-geared" vessels, include deck-mounted handling cranes, which can reduce overall capacity. These vessel-mounted cranes are sometimes required to facilitate loading and unloading of containers at ports without adequate shore-side cranes.

The Landing Craft Air Cushion (LCAC) is able to carry LOLO cargo, such as twenty-foot containers. Deck loading of LOLO cargo and containers is the least desirable method of transportation due to support requirements. The preferred method is for cargo to be mobile loaded on trailers or trucks for quick discharge using the RORO ramps. However, most containers are not shipped on chassis and truck assets will be limited.

LOLO cargo may be loaded into the LCAC using cranes from a self-sustaining vessel or an auxiliary crane ship. The LCAC must moor perpendicular to the ship, bow in to the ship, to prevent damage to craft propellor ducts. LCAC engines must be secured during LOLO cargo operations. This mooring procedure is possible only under Sea State 1, or ideal, conditions. The perpendicular mooring position cannot be maintained with the engines secured in high seas or winds. Relative motion between the craft and vessel combine with load pendulation during LOLO operations to create hazardous conditions which can cause craft damage and crew injuries. Cargo must be carefully lowered to avoid injuries to crew members or contact with LCAC cabins and powertrain assemblies on either side of the cargo deck. LOLO operations in conditions exceeding Sea State 1 are generally not considered practical.



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