Among the advantages of ro-ro vessels, it is necessary to highlight:

 

- High speed of loading and unloading operations due to movement under its own power or unloading by truck tractors.

 

- Possibility of integration into the system of multimodal transportation with other types of transport and container transportation.

 

- Creates opportunities for tourist travel by personal car, which makes tourist ferries in demand in the industry.

 

Car carriers

    Vessels of this type (Pure Carriers/Pure Car Truck Carriers) have a box-shaped hull to reduce the loss of useful area and a large number of ramps and lifts. 

    They are installed not only for the exit from the side at the stern and along the sides, but also in the interior space for movement between decks. Such vessels are used for transatlantic transportation and on shorter routes.

 

RoPax

    An abbreviation for passenger ferries with the ability to load vehicles on board.     

    For vessels with a capacity of 500 people and above, the name "cruise ferry" is used. 

    Most often, RoPax vessels are used for work in cabotage, but meet international requirements for passenger-class vessels. 

    Today, such transportation is characterized by geographical unevenness in the world, most of them are concentrated in the Northern Europe region.

 

RoLo

    A type of RO-RO vessel, for which only part of the cargo decks are accessible by ramps, and others only by cargo cranes. 

    As a result, they can simultaneously transport wheeled vehicles and a wide range of general cargo. In order to avoid excessive loads on the ramps, cargo is loaded into or unloaded from the holds by shore cranes.

 

ConRo

    This is a hybrid vessel that combines the capabilities of a ferry and a container ship. 

    The space under the main deck is used to accommodate vehicles, while the open deck is used to transport large-capacity containers. 

    In some cases, the division into container and vehicle zones can be done in a different way. For example, on one side there is a ramp for vehicle movement, and on the other side there are guides for installing containers. 

 

 

    The main difficulty of such vessels is the correct loading to maintain stability. At the same time, their sail area will be lower than that of other types. The first ConRo vessels were built at the beginning of the second half of the 20th century.

 

    Given that RO-RO accounts for a small part of the world fleet, their share of involvement in various accidents is much higher. 

    To prevent their occurrence, it is necessary to pay close attention to issues of ensuring safety at sea and during loading and unloading operations at the berth. 

    Increased attention should be paid to the condition of the cargo, primarily the availability of opportunities for its reliable fastening on board.

 

 

Among the potential sources of danger:

 

- absence, insufficient quantity or incorrect placement of fastening elements, their insufficient reliability;

 

- incomplete loading of liquid cargo in tanks, containers that can move and disturb the state of equilibrium;

 

- insufficient quality of maintenance of ramps and ramps on board;

 

- insufficient level of maintenance of cargo decks, their poor lighting;

 

- presence of moisture on the decks;

 

- careless movement of vehicles on the deck or reversing;

 

- errors in securing cargo, use of low-quality fastening material;

 

- non-compliance of the used fastening rigging with weather and climate conditions;

 

- presence of free play in the suspension of the transported vehicle.

 

    The wide use of RO-RO vessels is explained by the variety of cargoes they can carry, as well as the high speed of processing in ports. At the same time, the main problem of using a fleet of this category is the optimal use of cargo capacity due to the rational placement of vehicles. 

 

 

When organizing the loading of ro-ro vessels, the following points must be taken into account:

 

- when loading, it is necessary to rely on the recommendations provided by the shippers;

 

- the placement of vehicles or roll trailers must be carried out along the longitudinal axis of the vessel in one or more lines;

 

- the placement of vehicles should not be carried out across the standard fire curtains that ensure fire safety on the vessel;

 

- the vehicles are located as tightly as possible to prevent their movement along the deck, but with the preservation of space for the safe passage of the crew or passengers of the ferry;

 

- throughout the entire period of transportation, convenient access to fasteners and equipment, full control must be guaranteed;

 

- all evacuation routes and ladders between decks must be constantly free;

 

- cargo (transport) placement must not create obstacles for vessel control and its equipment, access to premises, safety equipment;

 

- for transport equipped with parking brakes, their use when installed on deck is mandatory;

 

- during transportation, it is prohibited to install roll trailers and other vehicles on standard supports, except in cases where special amplifiers are available on the deck;

 

- during transportation, it is prohibited to install roll trailers on their own standard supports, except in cases where they are specially designed for this;

 

- when installing roll trailers on special supports, they must be located between the wheels and the kingpin so as not to interfere with the tractor hitch;

 

- the choice of the method of installing vehicles on the deck in terms of ensuring safety must be carried out taking into account weather and climatic conditions.

 

 

    In the process of securing cargo spaces on RO-RO vessels, it is necessary to ensure the maximum permissible securing, while placing the chassis on jacks with the release of pressure from the hydraulic systems, if such is provided for by the design. 

    The latter allows to exclude the occurrence of emergency situations associated with leakage from air brake systems and loss of reliability of fixing of vehicles.

 

    During the operation of ro-ro vessels, their operators have to solve various problems associated with the placement of cargo and its features.

 

 

The latter for sea transportation are:

 

- a huge typology of cargo;

- a variety of cargo shapes, including complex ones;

- fastening features;

- the absence of transverse bulkheads and strength amplifiers;

- load restrictions;

- stability indicators, including in the case of rolling cargo.

 

    From the point of view of commercial transportation, the use of RO-RO vessels provides significant benefits. 

 

    At the same time, their shape and design features make them a source of increased danger and regular emergency situations.

 

 

Among the reasons for the increased accident rate of ro-ro vessels, it is necessary to highlight:

 

- the absence of internal bulkheads dividing the vessel into isolated compartments;

 

- the mobility of cargo spaces and difficulties with their reliable fastening;

 

- high sail area of ​​the side;

 

- significant metacentric height;

 

- restrictions on the placement of life-saving equipment. 

 

 

    According to IMO statistics for 2017, about two thirds of all casualties at sea are accounted for by RO-RO vessels, given that they make up a minimal share of the cargo and passenger fleet at the moment. 

    In such conditions, it is not surprising that the international organization pays increased attention to safety issues on RO-RO vessels. 

    Despite the new operating rules being adopted, the requirements for the design of ships cannot radically improve the situation.

 

    Research in this area shows that the main cause of emergency situations is cargo shifting with loss of stability, technical malfunctions of vessels or errors caused by violation of safety rules on board by the crew. 

 

    Taking into account the design features of rolling vessels and their increased danger, increased requirements are imposed on them for compliance with safety measures, since any error can cause an emergency situation with human casualties and the loss of the vessel.