Variations on the Ro-Ro Theme
Today the world ro-ro fleet can be subdivided into a number of different types. They include ships designed to carry freight vehicles only; to carry a combination of containers and freight vehicles and to transport cars without passengers. There are various other types and freight-only roro ships form about two thirds of the world ro-ro fleet at present. However, the best known ro-ro ships are ferries designed to transport commercial vehicles and private cars, together with large numbers of passengers, usually on short voyages.
Most ships of the Ro-Ro type, i.e. ships for the transportation of wheeled vehicles which may be driven into, and out of the ship, respectively, or which are adapted to take care of containers or other standardized cargo units which are handled by fork lift trucks or similar transportation means, are usually provided with a single deck only. Ships having two or more decks are provided with lifts for transferring the cargo vertically between the decks, or has built-in linclined ramps, making it possible to drive from one deck to an other. Both arrangements require a considerable amount of space, and especially the lift arrangements are expensive. The handling of the cargo in the vertical direction will further take more time than the driving on-board.
- Sto-Ro (Stowable Ro-Ro) -- Contrary to the Ro-Ro, no cargo remains on wheels but is directly loaded onto vessel decks. The stowage is similar to an open Load-on/Load-off (Lo-Lo) vessel; however, the cargo is brought on board either over a stern/bow quarter ramp or through a side port door. Vessel operations can turn to this concept of cargo handling as a means of combining the undoubted handling ad-vantages of the Ro-Ro (improved turnaround times) with the efficiency of a Lo-Lo (increased utilization of a ship's cubic capacity).
- Float-On/Float-Off -- A heavy deck semi-submersible vessel designed to permit oversized indivisible cargo being floated into position for deck stowage. The reverse procedure is used at the destination port where the load is floated from the submerged deck that is ballasted down for the outturn. The vessel travels with its deck and load above the water.
- Trot-On/Trot-Off -- Ro-Ro conversion or version in which vessel trailer decks are transformed into modern cattle pens capable of accommodating in excess of 2,000 animals. New installations include provision of fresh water through evaporation and increased tankage "barns" for 1,600 cubic meters of hay or straw and an air circulation plant.
- Con-Ro - Combination Container and Ro-Ro Vessels -- This design allows for flexibility of operation by incorporating container and other wheeled cargo handling capability. These vessels carry containers on and under deck forward and have a stem ramp with tween decks for the carriage of Roll-on/Roll-off cargo in the aft underdeck area. The Ro-Ro cargo may consist of over-sized pieces such as construction equipment, i.e., bulldozers and excavators, which are driven onto the vessel via the ramp. Containers can also be stowed on the Ro-Ro decks but are brought aboard on chassis and removed with forklift machines. If space and equipment is available the container can be left on its chassis during transport.
- RoPax - Ro-Ro / Passenger - Freight and passenger ferries (RoPax ferries) are designed to carry passengers and freight, and the emphasis may be on freight, or on passengers, depending on operator requirements. These ships may be thought of as several decks for passengers [to austere cruise ship standards], atop several decks for vehicles. Typical accomondations range from about 1,000 to about 2,500 passengers, and several hundred vehicles. Unlike ferries, which have passenger plane like seating for passengers for short distance trips of only a few hours duration, Ro-Pax vessels have stateroom accomodations for passengers for trips which may take the better part of a day to complete. These vessels have large decks for lorries, trailers and cars that are easy to load. In addition to facilities such as restaurants, amusement arcades and cinemas, there are also areas specifically for lorry drivers, with a separate dining room, showers and cabins.
- A ferry is any vessel used to provide transportation only between places that are no more than 300 miles apart, and to transport only - passengers, or vehicles, or railroad cars, which are being used, or have been used, in transporting passengers or goods. Unlike Ro-Pax vessels, which have stateroom accomodations for passengers, ferries have passenger plane like seating for passengers. The fundamental objective of ferry terminal design is to enable passengers and vehicles to proceed from the ferry to access a mode of continued travel. The internal layout of facilities reflects this concern for the convenience of passengers and their vehicles by providing simple and direct passenger/vehicle flow routes through the facilities. A tractor-trailer carried on a ferry with a container either loaded with cargo or empty will classify the vessel as a ferry and the goods within the trailer or container are looked upon as having arrived in the Customs territory by ferry.
Some current designs of roll-on/roll-off ferries for relatively short sea passages are twin-hulled designs. The engines are housed in the base of the hulls near the waterline, with power offtake shafts extending sternwards to the propulsors, which may comprise waterjets. These vessels are designed for high speeds, with small wetted hull areas to minimise drag from the water. Their loading decks are arranged to span the distance between the two hulls at as low a level as possible compatible with the seagoing ability required by the vessel and the rest of their superstructures are designed as far as possible with long low continuous lines to minimise aerodynamic drag and susceptibility to cross winds and to obtain the greatest possible stability for the vessel. A further design aim is to maximise cargo capacity.
RO-RO ships have also been developed to handle multicargoes, whereby they are enabled to transport different vehicles as a part of the cargo. In these ship types the cargo is transferred aboard by means of waggon and carriage pallets, which are carried along with the cargo to the port of destination. This method is applied particularly to transporting forest products. To increase loading flexibility, containers are also loaded on these pallets. Straddle carriers and trucks are also used for container handling. A high cargo space can be divided vertically in two or three sections by means of so-called hoistable car decks. The loading and unloading capacity of the ship is satisfactory. All in all, this method is, however, expensive on account of terminal facilities and special ship equipment. Space utilization and stowage efficiency are not good.
In 1992, the Washington State Ferry System decided three new Jumbo Mark II Ro-Ro Ferries were needed for its Bremerton and Bainbridge Island runs. The Jumbo Mark II was the first new auto ferries built for Washington State Ferries [WSF] in 20 years. While the name didn't show much imagination, it isn't entirely unjustified. The ferries are modern versions of the Jumbo Class ferries Spokane and Walla Walla. The Jumbo Mark II boats are designed to separate walk-on and auto traffic. The Mark II's hold 2,500 passengers, 500 more passengers than the Jumbos. The increase bumped their size up 20 feet. At 460 feet, they are the largest double-ended auto ferries in the world. While carring 500 more passengers, the auto capacity only went up by about 12, to 218. Passeger capacity was more important on the Bainbridge run, where the 2,000 passenger Jumbos were filling to capacity on the morning and evening commuter runs.
As of early 2006 the largest PCC in service was the MV Mignon, owned and operated by Wallenius Wilhelmsen Lines of Sweden, it can carry some 7,200 car equivalent unite [CEU]. The Mignon was the first of five Wallenius Boheme-class vessels to be stretched by 28 metres to 228 metres LOA. The lengthening results in making these the biggest car carriers in the world. The Mignon unloads cars, pleasure craft, etc and load export cars, trucks and haulers, predominantly for the US, at Port of Göteborg's Car Terminal. In addition to the five vessels stretched or to be stretched, Wallenius Lines had a newbuilding program of six pure car/truck carriers, three of 6,500 and three of 8,000 cars capacity.
Five of the ships will be built at the Daewoo Shipyard in Korea. The first two new vessels had a cargo capacity of 6,700 cars and will be delivered at the end of 2006. The other three, each with a cargo capacity of 8,000 cars, were delivered in late 2007 and early 2008. The ships were operated by the subsidiary Wallenius Wilhelmsen Lines. The sixth ship, with a capacity of 6,400 vehicles, is being built at Hyundai Heavy Industries in Korea and will be operated by the Wallenius Korean subsidiary, EUKOR.
Wallenius Lines reached an agreement in early 2006 with Wilh. Wilhelmsen ASA regarding the sale of two LCTC newbuildings at Daewoo Shipbuilding & Marine Engineering. Each vessel has a capacity of 8,000 cars and is due for delivery in 2009. The Wallenius Lines newbuilding program comprised eight vessels to be delivered between 2006 and 2008.Superstar is Tallink’s first ferry designed in Italy, by interior designers Carlo Ciribi and Alessandro Cestaro, who also designed the fast ferry’s shops. The vessel, which has the capacity to carry 2,080 passengers on the two-hour crossing. Tallink-Silja Line commenced operations of its new high speed vessel, the M/S Superstar, on the Helsinki-Tallinn route on 30 April 2008. M/S Superstar, together with the M/S Star delivered in Spring 2007, will jointly operate as the Tallink Shuttle service. Tallink Shuttle is the new service concept “combining fast and comfortable travel between the two capital cities,” said the company. The Tallink Shuttle vessels are designed to be more environmentally friendly, characterised by the green colour of their hulls. Both vessels consume less fuel, have modern technical solutions and create smaller waves compared to smaller high speed crafts, according to the company. Built in the Fincantieri shipyards in Italy, M/S Superstar was designed by Italian interior designers Carlo Ciribi and Alessandro Cestaro. At 175m long and 28m long, the vessel has ten decks, can hold 2,080 passengers, and has 1,930 lane meters for vehicles.
Stena Line has a modern fleet of 35 vessels and Europe’s most comprehensive network with 18 ferry routes in Scandinavia and around the UK. Stena Line goes from 2010 between Hoek van Holland and Harwich sail with two ' superferries ', which is currently still under construction at the yard of Aker Yards in Wismar in Germany. The new ships under construction requires an investment of 400 million ruyim. With their 240 metres in length and a total of 5,500 meters at essay space for trucks and passenger cars, they are the largest world RoPax-ferries . The number of vehicles that these ships can transport rises by more than 30 percent.
In 2010 Stena Hollandica was the world’s largest ropax ferry in terms of combined passenger and freight capacity. The first of two large superferries, built by Nordic Yards in Wismar, Germany, was recently put into service with Stena Line on the North Sea run between Harwich and the Hook of Holland. Stena Line’s largest ever investment of over £375 million ($586 million) has been spent on building the two new 62,000gt vessels, with the Stena Hollandica now in service and the Stena Britannica scheduled for delivery imminently. The 11,600 dwt newbuildings measure 240m long, 32m wide and have a draught of 6.4m. The largest ferries of their type in terms of combined passenger and freight capacity, each has 5,500 lane metres over four decks interconnected by ramps and capable of accommodating 230 cars plus 300 freight vehicles. Discharging and loading is by means of a 17m wide stern ramp and a 7m wide bow ramp facilitating double tier loading/discharging. The vessels are fitted with 185 refrigerated cargo sockets. Passenger capacity is 1,200 and the accommodation, which is situated on decks 10 and 11, consists of 438 two-bed cabins and 100 five-bed cabins giving a total of 1,376 beds onboard. The 538 cabins all have a modern en suite bathroom while larger windows have been installed in both bathroom and main cabin areas to provide a feeling of space and light.
On March 2011, the French company Brittany ferries revealed a partnership with the French subsidiary of STX group in order to produce the design of a new environmental class of ferries. If this project successfully pass the stage, Brittany Ferries will be the first company to order a vessel of the "Pegasis" class. The vessel will be Gas powered. In January 2012, specification of the ship have been released: 52,500 Gt; 210m long; 31m wide; 25 knots; 2,400 passengers; 650 cars; 40 trucks; 650 cabins.
|Join the GlobalSecurity.org mailing list|