A ro-ro vessel, or roll-on/roll-off ship, is a vessel used to carry wheeled cargo loaded through using a built-in ramp usually located in the stern (backside) of a ship. This cargo handling system normally transports trailers, chassis, cars, rolling machinery, or other cargo typically wheeled or loaded using a fork lift.
- Industry and Classification
The roll-on/roll-off system that we think of today can be traced back prior to the civil war. Originally these ships were specifically designed to transport trains over large rivers. These ships had built in rails that allowed the railcar to roll straight on to the ship. The beginning operations of this method can be traced to the Firth of Forth ferry in Scotland which began operations in 1851. It wasn’t until after WWII where the military had successfully used ro-ro technology in constructing their tank landing craft and significantly shortened loading and unloading times that merchant ships also adopted the technology. An increase in automotive and oceanic shipping spurred the popularity of this developing technology.
Initially when cars were being shipped across the sea they were lifted by shore side gears and a small number of cars were placed on ‘tween decks on a general cargo vessel. Bulk carriers then became fitted with folding decks and were able to carry a larger amount of cars, typically as backhaul shipments. As the desired quality for shipping and the overall customer demand increase, these factors assisted in the industry developing pure car carriers (PCC’s). These vessels led to the development of roll-on/roll-off loading and discharge which was a combination of internal and external ramps that allowed cars the possibility to drive on to and off of different decks on the ship which is where most of the industry stands today.
2. Industry and Classification
Ro-ro shipping is typically conducted between North American and Europe and also Europe and the Middle East. Even in these areas the availability and market share is much less than standard containerships. But with its ability to quickly load and unload a variety of vehicles ro-ro shipping is a preferred type of shipping among the military. With the technology available today, ro-ro vessels can be customized with a variety of ramps and decks to fit the needs of an individual company or port.
Spurred by the increase in automotive transportation, the pure car carrier (PCC) was developed and is used today for new automobiles being transported by ship
The pure car and truck carrier (PCTC) is very similar to the pure car carrier but it has special decks that can adjust for vertical clearance or has been reinforced to support heavier cargo.
A combination of a container ship and a ro-ro vessel where the lower deck is used for vehicle storage and the top deck is stacked with seagoing freight containers.
Large, Medium Speed Roll-on/Roll-off is a class of Military Sealift Command cargo ships
Ro-ro vessels are a fairly specialized form of sea freight transportation. The advantages that it holds are it can take advantage of smaller ports because the cost and complexity of the loading and unloading process are easier. The expensive loading equipment and staff are not needed when using this type of loading. The ro-ro process has made the entire loading and unloading process much safer and efficient. This capability for rapid loading and unloading can be taken advantage of by many, including the military.
The main disadvantage of ro-ro shipping is the volume utilization. Considering cargo is rolled on deck and sitting on wheels, things are not able to be stacked on top of each other. In order to be able to maneuver some of this cargo, a lot of space is needed for loading and unloading. This sometimes limits the capacity to less than half of what a similarly sized lo-lo vessel could carry.
Pike, John. “RO-RO Ships.” GlobalSecurity.Org. N.p., 07 July 2011. Web. 18 Nov. 2012. <http://www.globalsecurity.org/military/systems/ship/ro-ro.htm>
Team: FS12_01 (11/20/12)