What are RORO Ships?

Ro-Ro is an acronym for Roll-on/roll-off ships, which are vessels used to carry wheeled cargo, such as vehicles.

The roll-on/roll-off ship was defined in the November 1995 amendments to Chapter II-1 of the International Convention for the Safety of Life at Sea (SOLAS), 1974, as being “a passenger ship with ro-ro cargo spaces or special category spaces.”

The ro-ro ship is different from a Lo-Lo (lift on-lift off) ship, which uses a crane to load the cargo. The vehicles in the ship are loaded and unloaded by means of built-in ramps. Normally, these ramps are made towards the stern (backside) of the ship. In some ships, they are also found on the bow side (front) and the sides. The vessel can be of both military and civilian types.

Ro-Ro vessels were built in the 19th century to transport trains, too wide for the bridges, across rivers.

An example of a Ro-Ro vessel is the Firth of Forth ferry, which started operations in 1851. The rails were laid on the ship so that it could be connected to the ones on land. A train would then roll onto the ship and then roll off at the other end.

There are different types of ro-ro vessels, such as ferries, cruise ferries, cargo ships, and barges.

The ro-ro vessels exclusively used for transporting cars and trucks across oceans are known as Pure Car Carriers (PCC) and Pure Truck & Car Carriers (PCTC), respectively.

Related Read: The Dangers of Ro-Ro Ship Design: A Naval Architect’s Perspective

Unlike other cargo measured in metric tonnes, ro-ro cargo is measured in lanes in meters (LIMs).

LIM is calculated by multiplying cargo length in meters by the number of decks and by its width in lanes. The lane width will differ from vessel to vessel and there are a number of industry standards.

One of the largest ro-ro passenger ferries is MS Color Magic. It weighs 75,100 GT (Gross Ton) and entered service in September 2007 for Color Line. It was built in Finland by Aker Finnyards. The ferry is 223.70 m long and 35 m wide and can carry 550 cars and 1270 lane meters of cargo.

The ro-ro passenger ferry with one of the highest car-carrying capacity is the Ulysses. The ferry was named after a novel by James Joyce and is owned by Irish Ferries. It entered the service on 25 March 2001 and operated between Dublin and Holyhead. It weighs 50,938 GT and is 209.02 m long and 31.84 m wide. It can carry 1342 cars and 4101 lane meters of cargo.

Related Read: Different Types of Ferries Used in the Shipping World

Advantages of a Ro-Ro ship

A ro-ro ship offers several advantages over traditional ships. Some of the advantages are as follows:

• For the shipper, the advantage is speed. Since cars and lorries can drive straight onto the ship at one port and then drive off at the other port within a few minutes of the ship docking, it saves a lot of time for the shipper.
• It can also integrate well with other transport developments, such as containers. Customs-sealed units have enabled frontiers to be crossed with the minimum of delay. Therefore, it increases the speed and efficiency of the shipper.
• The ship has also proved extremely popular with holidaymakers and private car owners. It has significantly contributed to the growth of tourism. A ro-ro vessel allows a person to take his car from one country to another by sea.

Variations of a ro-ro ship

The certain variations of a ro-ro ship are as follows:

Pure Car carriers(PCC) /Pure Car Truck Carriers (PCTC)

Pure Car carriers(PCC) / Pure Car Truck Carriers (PCTC)have a box-like framework, with ramps to load and unload the cargo. The pure car carrier is used to transport only cars, whereas PCTC is used to transport all types of vehicles.

These consist of a quarter ramp in the stern, two ramps on both sides, covered internal ramps, and hostable decks used to transfer the cars into multi-level decks. Vehicles drive directly into the ship and via an internal ramp system to various decks.

ROPAX

ROPAX is an acronym for roll on/roll off a passenger. It is a ro-ro vessel built for freight vehicle transport with passenger accommodation. The ships with facilities for more than 500 passengers are often referred to as cruise ferries.

RoPax is used for short sea transport. These vessels comply with the international standards which apply to a passenger ship and to a Ro-Ro. ROPAX traffic is unevenly distributed all over the world. Its traffic can mostly be found in the seas of Northern Europe

RoLo

RoLo is an acronym for roll-on lift-off vessel. It is also a hybrid vessel type with ramps serving vehicle decks, but the other cargo decks are accessible only by crane.

These vessels can carry Vehicles and general cargo or heavy metals. Since the weight of general cargo items or Heavy metal pieces may exceed the payload of the ramp, ship/shore cranes can load and discharge the cargo directly into the hold.

ConRO

The ConRo vessel is a hybrid between a ro-ro and a container ship. This type of vessel uses the area below the decks for vehicle storage while stacking containerized freight on the top of the decks.

In some vessels, there are arrangements where the vessel is divided into 2 parts. The underdeck of one side has cell guides wherein the containers can be loaded, and the other side’s underdeck has all arrangements for carrying cars or other such vehicles. Full cargo carrying space on deck is used for carrying containers.

Related Read: Top 10 World’s Largest Container Ships In 2019

The loading and discharging operations in these vessels need utmost care and diligence, as the weight distribution difference may affect the vessel’s stability. The windage area of these types of vessels is less than that of any other Ro-Ro vessels. They were introduced in the 1950s.

Roll-on/Roll-off Ships Stowage and Securing of Vehicles

Principal Sources of Danger

Though Ro-Ro vessels make up a very small proportion of the Merchant marine tonnage, many accidents involve them, giving rise to far worse consequences. It is very important to understand the “Sources of Danger “that lead to such petrifying situations. These sources of danger affect the safety of roll-on/roll-off vessels as well as the passengers/crew in them.

• The unacceptable condition of the consignment constrains it from being properly lashed for Sea. Examples are insufficient numbers, incorrect positioning of securing points, weak securing points, etc.
• The free surface effect in tank vehicles and tank containers which are slack;
• Poorly maintained ramps, lifts and bow and stern doors;
• Poorly maintained, inadequately illuminated or badly planned decks;
• Wet Decks;
• Vehicles being moved negligently on vehicle decks and ramps;
• The reversing of road vehicles on vehicle decks and ramps;
• Insufficient or incorrectly applied lashings or wrong use of Lashing equipment, or of inadequate strength with regard to the mass and centre of gravity of the vehicle and the weather conditions likely to be encountered during the voyage;
• Free play in the suspension of vehicles;

Related Read: 8 Reasons That Make Ro-Ro Ship Unsafe to Work On

Stowage

The Ro-Ros are true workhorses of the Sea. Their versatility in transporting diverse cargo and short port stays show their efficiency. The cargo carrying capacity of any vessel increases the vessel’s earning efficiency. So, it is very important to optimally use cargo space, which has been inherently problematic with the Ro-Ro concept, in order to contrive optimal stowage plans.

Below are the few essential points we must remember while stowing cargo in Roll on-Roll Off vessels:

• Shippers’ special advice or guidelines regarding handling and stowage of individual vehicles should be observed.
• Vehicles should, so far as is possible, be aligned in a fore and aft direction.
• Vehicles should not be stowed across water spray fire curtains.
• Vehicles should be closely stowed athwartships so that, in the event of any failure in the securing arrangements or from any other cause, the transverse movement is restricted. However, sufficient distance should be provided between vehicles to permit safe access for the crew and for passengers getting into and out of vehicles and going to and from accesses serving vehicle spaces.
• Safe means of access to securing arrangements, safety equipment, and operational controls should be provided and properly maintained. Stairways and escape routes from spaces below the vehicle deck should be kept clear.
• Vehicles should not obstruct the operating controls of bow and stern doors, entrances to accommodation spaces, ladders, stairways, companionways or access hatches, fire fighting equipment, controls to deck scupper valves and controls to fire dampers in ventilation trunks.
• Parking brakes, where provided, of each vehicle or of each element of a combination of vehicles should be applied.
• Semi-trailers should not be supported on their landing legs during sea transport unless the landing legs are specially designed for that purpose, and so marked (see paragraph 4.1.4).
• Semi-trailers should not be supported on their landing legs during sea transportation unless the deck plating has adequate strength for the point loadings.
• Uncoupled semi-trailers should be supported by trestles or similar devices placed in the immediate area of the drawplates so that the connection of the fifth-wheel to the kingpin is not restricted.
• Depending on the area of operation, the predominant weather conditions and the characteristics of the ship, freight vehicles should be stowed so that the chassis is kept as static as possible by not allowing free play in the suspension. This can be done by securing the vehicle to the deck as tightly as the lashing tensioning device will permit or by jacking up the freight vehicle chassis prior to securing or, in the case of compressed air suspension systems, by first releasing the air pressure where this facility is provided.
• Since compressed air suspension systems may lose air, adequate arrangements should be made to prevent the slackening off of lashings as a result of air leakage during the voyage. Such arrangements may include the jacking up of the vehicle or the release of air from the suspension system where this facility is provided.
  

There are also specific difficulties faced by cargo operators in the stowage of cargo in Ro-Ro Ships:

• Cargo stowage on deck
• Various types or varieties of Cargo
• Shape of Cargo
• Securing the cargo within the unit
• The lack of transverse bulkheads
• Loading conditions
• Stability and rolling periods

Securing

Proper securing of any cargo is of utmost importance to the Safety of life at sea. The shape of a Ro-Ro is such that any condition of instability can lead to a disaster. Even according to a DNV survey, ”Shifting of Cargo” has been one of the major reason for Marine accidents involving Ro-Ro’s.

Related Read: The Basics of Cargo Lashing and Securing on Ships

Below are some important points to consider:

• Securing operations should be completed before the ship proceeds to sea.
• Persons appointed to carry out the task of securing vehicles should be trained in the use of the equipment to be used and in the most effective methods for securing different types of vehicles.
• Persons supervising the securing of vehicles should be conversant with the contents of the Cargo Securing manual.
• Freight vehicles of more than 3.5 tonnes should be secured in all circumstances where the expected conditions for the intended voyage are such that movement of the vehicles relative to the ship could be expected. So far as is reasonably practicable the securing arrangements should be adequate to ensure that there will be no movement from any cause which will endanger the ship.

How safe are Ro-Ros

Commercially, Ro-Ro’s have always been successful due to their flexibility, integration, and operational speed. Despite being commercially successful, Ro-Ro’s has always been criticised for its design, and it is also said to be one of the reasons for the disturbing accidents involving Ro-Ro’s. The main concerns are from a safety point of view. Some of them are listed below:

• The lack of internal bulkheads
• Cargo access door
• Stability
• Low freeboards
• Cargo stowage and securing
• Life-saving appliances
• The crew

As per IMO’s circular released in January 2017, nearly 2/3rd of the lives lost at sea was from the accidents of Ro-Ro’s only. This shows that the effect of Marine accidents involving Ro-Ro’s has enormous consequences. Many steps were taken by IMO in order to reduce these accidents and some of them left an implacable effect on this industry too. Improving safety onboard Ro-Ro’s has been one of the major topics of discussion.

The introduction of new laws,  rules or conventions doesn’t change the picture. One of the studies on the causes of major accidents reflects that shifts in cargo and operational faults have been the major causes of all these accidents. These accidents were the result of improper implementation of the regulations and Human errors.

This type of ship is more complex both in construction and operation.so any error can lead to catastrophic consequences because of the Passengers present on the ship.

You might also like to read:

• What are Bulk Carrier Ships?
• What are Container Ships; History, Types And Design
• What are Tanker Ships?
• What are Gas Carrier Ships?
• What is a Cable Laying Ship?

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About Author

Raunek Kantharia is a marine engineer turned maritime writer and entrepreneur. After a brief stint at the sea, he founded Marine Insight in 2010. Apart from managing Marine Insight, he also writes for a number of maritime magazines and websites.

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