RO-RO Ship History
To achieve an increased flexibility of goods transport ships to a certain degree, the Ro-Ro ship was developed, with a weather deck for the transport of particularly containers and with a plurality of tween decks that may be used for the transport of trailers or e.g., cars which may be loaded using stern ramps.
The modern roll-on/roll-off ship can trace its origins back more than one hundred years to the early days of the steam train. Ships were specially designed to take trains across rivers which were too wide for bridges: the ships were equipped with rails, and the trains simply rolled straight on to the ship, which sailed across the river to another rail berth where the train would roll off again. An example is the Firth of Forth ferry in Scotland which began operations in 1851.
It was not until the Second World War, however, that the idea of applying the ro-ro principle of road transport became practicable - and was used in constructing the tank landing craft used at D-Day and in other battles. The principle was applied to merchant ships in the late 1940s and early 1950s. It proved to be extremely popular, especially on short-sea ferry routes, encouraged by technical developments on land as well as sea, notably the increase in road transport. For the shipper, the ro-ro ship offered a number of advantages over traditional ships, notably speed. As the name of the system implies, cars and lorries can drive straight on to a ro-ro ship at one port and off at the port on the other side of the sea within a few minutes of the ship docking.
Until the 1950s, anyone wishing to take a motor vehicle across the sea by ship had to load and unload it by crane - a time-consuming, expensive and somewhat risky procedure. At the same time, the growth of motor transport made it imperative that some means of speeding up the process should be found. The solution was the ro-ro, a design that may have originated with the tank landing craft configuration which was developed during the Second World War.
It was an appealingly simple concept. Simply place a door at either end of the ship, connected by a huge, unrestricted deck area, and you have created what it is in effect a floating bridge. Vehicles drive on at one end and off at the other. The ro-ro concept seemed to provide all the answers - until something went wrong.
Ro-ro ships also integrate well with other transport development, such as containers, and the use of Customs-sealed units (first introduced in the late 1950s) has enabled frontiers to be crossed with the minimum of delay, thereby further increasing speed and efficiency for the shipper. Ro-ros have also proved extremely popular with holiday makers and private car owners and have significantly contributed to the growth of tourism. Until the early 1950s someone wishing to take his car from one country to another by sea had to get it loaded into the ship's hold by crane, a time-consuming and expensive process. The development of the ro-ro car ferry changed all that and many ports boomed as a result.
In the United Kingdom, Dover's first pair of drive-on berths was opened in 1953. Until then the port had handled only 10,000 crane-loaded cars each year and forecasts that the berths would enable the port to handle ten times that many must have seemed decidedly optimistic. But the 100,000 figure was exceeded in the first year and by 1985 Dover was handling over 2.5 million vehicles and units through nine ro-ro berths. By 1994 the total had risen to more than 4.5 million. By 1994 around 4,600 ro-ro ships were in operation around the world.
The movement of cars by sea started with the transport of small numbers of vehicles in general cargo vessels, many of which were then modern ships in liner service (i.e., following a regular schedule). These liner vessels were usually 'tween deckers, ships whose deep lower holds were separated from the upper deck by one or two intermediate ('tween=between) decks. Cars were lifted to and from the 'tween decks by shoreside or ship's lifting gear. The number of cars that could be carried in a ship was limited, the liner's discharge and loading ports might require extensive land transport of the cars, and the cars were susceptible to damage in the lift on/lift off loading process.
Next, bulk carriers were fitted with folding decks. Emphasis was on bulk cargoes with cars as backhaul. The demand for movement of large lots of cars led to their shipment in bulk carriers, open hold vessels, generally large, used for the carriage of cargoes shipped in bulk such as grain, ores, and coal, and fitted with folding decks on which the cars were stowed; cars were loaded by the lift on/lift off method. Bulk carriers were able to carry larger quantities of cars, but the cars were still exposed to damage in the loading and discharge process, risked being dirtied by residue from previous cargoes like coal, and loading and discharge port selection was driven by the needs of the bulk cargoes, cars being the secondary or backhaul cargo.
The growing volume of cars moving by sea and the demands of the car shippers for high quality service led to the design and construction of PCC's, vessels dedicated to the carriage of cars and, at least in intent, optimized for that purpose. One of the most notable features of the PCC was roll on/roll off loading and discharge. A series of external and internal ramps made it possible to drive the cars onto the ship and to their stowage location, and to discharge by the same method. This roll on/roll off loading and discharge resulted not only in reduced in-port time, but in greatly reduced handling damage to the cars as well. Furthermore, since the PCC was optimized for the carriage of cars, a relatively light cargo, their design could incorporate a much finer hull than the car-bulkers, permitting more favorable speed and fuel consumption characteristics.
Automobile carriage in PCC's, as compared with carriage in car-bulkers, resulted in faster transit time, less damage, no contamination by residue from previous dirty cargoes and the routing and port selection flexibility available to a primary cargo. The advantages of PCC's over car-bulkers were sufficient to impel many vehicles manufacturers to bar shipment of their product in car-bulkers. With all the advantages the PCC has, however, it remains a highly specialized vessel which is unsuited to other than roll on/roll off (RO/RO) cargoes and which has little opportunity to find backhaul cargoes of this type.
They are particularly popular in Europe, and trading patterns reflect this. Whereas pure container ships are to be found in large numbers operating between Europe and North America, Europe and Japan and Japan and North America, ro-ros operate primarily between Europe and North America and Europe and the Middle East, although there is an important trade between North America and the Caribbean.
Vehicle transport logistics is going through changes worldwide. Major producers have established and keep on establishing factories in their main export countries, to be in close proximity to end-users. The seasonal character of transports is growing and vehicle transport volumes are decreasing. Car parts and components are transported in increasing quantities. The freer market places demands on greater flexibility in handling different bulk or general cargo, better suitability for handling port and customer-specific small batches etc. on the ships of tomorrow. Economical use of ships calls for a better transport efficiency also during the return voyage. This is often a problem in current ship types. Loading and unloading no longer takes place in only two ports; on the contrary, a ship may have to make 5 to 10 port calls.
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