Construction and operation of cargo and

To load and unload oil products or other liquid cargo and distribute cargo among tanks, tankers are equipped with special cargo pipeline systems that allow these operations to be carried out. The remaining cargo from the tanks, not selected by the cargo system, is pumped out through a stripping system, which is basically similar in design to the cargo system, but has a significantly lower capacity, a higher pump suction height and smaller pipeline diameters. On ships of small deadweight, they are limited to one system that combines the functions of cargo and stripping.

Cargo systems on tankers provide for the possibility of receiving and delivering cargo from any side and from the stern of the vessel. For this purpose, the inlet and outlet pipes of the cargo system are located in the middle part of the main deck along both sides of the vessel symmetrically to the center plane. From the system of inlet and outlet pipes, the cargo line is extended to the stern of the vessel.

Cargo operations (draining and loading of petroleum products) must be carried out with closed inspection eyes of tanks, which, in turn, are equipped with fire-retardant nets.

Displacement of air and gases from tanks during loading, as well as filling of tanks with them during draining, must be carried out through a gas outlet (“breathing”) system (see section 5).

There are several standard solutions for the implementation of cargo systems on tankers. The ring system is used on tankers in which the cargo pump room (CPS) is located in the middle of the vessel, between the cargo compartments; linear system - on tankers in which the pump room is located behind all tanks, between the cargo tanks and the MKO; cargo system with bulkhead bypass clinkets - on tankers with aft-mounted gas pumping equipment.

Ring system cargo pipeline is common on ships of early construction and small deadweight.

The system has relatively high maneuverability and survivability. The disadvantage is the high cost, a large number of fittings and complexity of operation.

Linear system cargo pipeline has become most widespread, especially on large-capacity tankers. This system, compared to the ring one, is easier to operate and cheaper to build, but has less survivability (see Figure 1.1).

I-IV - group of tanks; - - - - cargo, -.-.-.-.- ballast pipelines

Figure 1.1 - Diagram of the cargo and ballast pipelines of the Leonardo da Vinci tanker

The requirements developed by Shell and British Petroleum apply to the large-tonnage tankers they charter:

The cargo system, taking into account the breakdown of the cargo tank area, must ensure the transportation of at least 2 types of cargo in the proportion of 50%:50%, or 25%:75%;

Both simultaneous and sequential unloading should be possible (partial mixing of cargo in pipelines is allowed);

The performance of the cargo system must ensure unloading (including stripping) within 15 hours at a pressure of at least 1.15 MPa;

Loading of homogeneous cargo must be carried out at an intensity of 10% per hour of the net carrying capacity, and ballast operations must be carried out simultaneously so that at any time the vessel has a load of at least 30% of the full deadweight to ensure seaworthiness;

The middle of the cargo manifold must be located amidships of the ship or no more than 3 m from it in any direction;

The height of the centers of the connecting flanges above the deck should be 0.9 m; at a higher height, a stationary working platform should be installed, spaced from the centers of the flanges at a distance of 0.9 m;

The cargo manifold must have at least four branches with flanges with a diameter of 406 mm, installed so that the distance between centers is at least 2.1 m, and the distance from the side to the DP is 4.6 m.

To connect the cargo manifold from standard valves to shore hoses, the requirements stipulate that the vessel be equipped with a set of adapter connections for flanges 101x203 mm, 101x254 mm, 101x 304 mm;

Between the clinkets of the cargo manifold and the adapters, spacers 400 mm long are installed, the support of which must be designed for a load from the hoses equal to 4 tf.

In the cargo pumping room, 2...4 cargo pumps (FP) with a capacity of (3...6) are installed. 10 3 m³/h and (9…12) . 10 3 m³/h on supertankers. Large tankers use centrifugal pumps with a steam turbine or electric drive (horizontal or vertical). The horizontal drive located in the MKO increases its length. The vertical drive (Figure 1.2) is shorter, the main drives are located lower, but it creates difficulties with its alignment.

1 - turbo drive; 2 - gas-tight seal;

3 - swivel joint; 4 - pump

Figure 1.2 - Vertical cargo pump

The GN pressure is 1.13 – 1.45 MPa. The total power of the gas pump reaches 0.5 Ne of the tanker. On old and small tankers, horizontal piston hydraulic pumps are used with a productivity of 100-400 t/h. They are characterized by a higher suction height, which ensures their use as stripping pumps (SP). Rotary pumps can also be used as pumps.

Some product carriers, gas carriers and chemical carriers use hydraulically driven submersible hydraulic pumps.

GN and ZN differ in productivity, so the time for complete stripping is 30% of the total tanker unloading time.

The presence of two redundant systems increases the cost of the ship, clutters the gas and cargo equipment, and complicates the automation of cargo operations, so there is a tendency to abandon the stripping system. Listed below are some ways to resolve this issue.

Gravity drain systems from British Petroleum (see Figures 1.3, 1.4). They are also used on the domestic tankers Sofia (see Figure 1.5).

The system is based on the free flow of oil through the bulkhead clinker doors that connect all the cargo tanks, the oil flows into the aft compartment and is taken by the gas pump, which operates at maximum productivity, and as the tanker empties, the trim to the stern increases.

An ejector is used to ensure reliable suction, operating on oil, which sucks oil from the aft compartment and pumps it into a settling tank located above the gas pump, so that the oil from it creates sufficient suction support for the gas pump (Figure 1.6).

1 - additional cutting blade on the receiving branches of the stripping pipeline; 2 and 3 - cargo and stripping pumps; 4 - deck cargo pipeline; 5 - secant blades between the inlet pipes

Figure 1.5 - Diagram of a cargo pipeline with bulkhead bypasses and clinkers for a tanker of the Sofia type (first series)

1 - stripping ejector; 2 - settling tank; 3 - pump room;

4 - cargo pump; 5 - cargo tank; 6 - receiving pipe of the cargo pump;

7 - receiving pipe of the stripping ejector

Figure 1.6 - Method of filling the cargo pump during stripping

cargo tank

"Sentry-Strip" system is equipped with a vacuum tank at the gas pump suction, in which, when the head pressure decreases, a vacuum is created, sucking in oil and increasing the gas pump head (Figure 1.7). As the level in this tank decreases, the valve on the HN suction closes (see section 2).

1 - air separator; 2 - differential pressure sensor; 3 - valve drive on discharge; 4 - butterfly valve; 5 - pneumatic valve; 6 - vacuum tank; 7 - vacuum valve; 8 - non-return valve; 9 - vacuum pump; 10 - electric drive of the vacuum pump; 11 - air filter; 12 - air filter refrigerator; 13 - vacuum gauge; 14 - pressure gauge; 15 - air supply valve.

Figure 1.7 - Scheme of the "Sentry-strip" system

There is a system with a vacuum tank that reduces the speed of the GN turbo drive as the pressure falls.

The Prima-vac system (Figure 1.8), with a decrease in backwater, increases the recirculation of oil at the suction of the centrifugal pump and prevents its failure.

All these systems increase the operating time of the GN at full capacity. An advantage is given to tankers with a double bottom, which constantly have sufficient GN support (Tankers “Crimea”, “Pobeda”, Figures 2.1, 2.2, “Mobil-Pegasus”).

1 - cargo pump; 2 - recirculation tank; 3 - Prima-vac valve;

4 - automatic valve; 5 - air outlet pipe; 6 - recirculation line; 7 - valve on the pressure line; 8 - air line control valve

A tanker is a specialized cargo-type vessel that can be adapted for both sea and river routes. Water transport is designed for transporting liquid cargo. Ocean supertankers, which are used not only for transporting oil, but also for storing it, are considered the largest in their series.

One of the largest supertankers

The largest tanker in the world was launched from the stocks in 1976. Its creator was Royal company Dutch Shell, and the ship itself was named Batillus. For the construction of a water vehicle About 70 thousand tons of metal and approximately 130 million dollars were spent. In 1973, there was a global oil crisis, as a result of which the cost of raw materials increased significantly. This led to a significant reduction in cargo turnover. The company that created the tanker had the intention of stopping, but the contract signed two years before the start of construction did not allow this. Breaking the agreement would entail significant costs. Today the only competitor of the vessel is in the world,

Technical characteristics of the vessel Batillus

Immediately after completion of construction, the ship performed only its minimum standard: it carried out only 5 voyages during the year. Since 1982, water transport has been idle for more time than it was used for its intended purpose. In 1982, the owner of the ship decided to sell it for scrap at a price of $8 million. The structure of the tanker included about 40 independent tanks, the total capacity of which is 677.3 thousand cubic meters. Thanks to the division into compartments built into the design, the vessel could be used to transport several types of hydrocarbons simultaneously. The project reduced the risk of accidents and the likelihood of ocean pollution. Oil was loaded into the largest tanker in the world by four pumps with a capacity of approximately 24 thousand cubic meters per hour. The total length of the vessel was 414 meters, and the deadweight (that is, the total carrying capacity) corresponded to 550 thousand tons. did not exceed 16 knots, and the duration of the voyage without refueling and resupply was 42 days. For maintenance of a floating structure by four power plants 330 tons of fuel were consumed per day.

Change of generations

After the Batillus, which had two five-blade engines and a 64.8 thousand horsepower 4, was used as storage since 2004 and was scrapped in 2010, the Knock Nevis took its place. During the history of its existence, Batillus has changed great amount owners, changed its name many times and was cut into scrap metal with the name Mont under the flag of Sierra Leone. The second largest tanker in the world is the Knock Nevis, the construction of which, like its predecessor, was completed in 1976. The ship acquired its enormous size three years later, after reconstruction. As a result of modernization, the tanker's deadweight approached 565 thousand tons. Its length increased to 460 meters. The ship's crew is 40 people. The tanker's engine turbines are capable of reaching speeds of up to 13 knots thanks to a total power of 50 thousand horsepower.

Seawise Giant, or the story of the Knock Nevis

The largest oil tanker in the world, which was built in the 20th century, is called Seawise Giant. The design of the vessel began before the era of double-decker tankers. At the moment, the vessel's analogues, according to experts, can only compete with floating cities with houses, offices and full-fledged infrastructure, the projects of which are just beginning to be considered by experts. Construction of the vessel began in 1976. Initially, its deadweight was supposed to be 480,000 tons, but after the bankruptcy of the first owner, tycoon Tung decided to increase its carrying capacity to 564,763 tons. The ship was launched in 1981, and its main purpose was to transport oil from fields to Iran. Later, the ship transported oil from Iran. During one of the voyages it was sunk in the Persian Gulf.

Magical rebirth

The largest oil tanker in the world, the Seawise Giant, was raised from the ocean floor near Kharg Island in 1988 by Keppel Shipyard. The new owner of the tanker was Norman International, which spent 3.7 thousand tons of steel to restore the vessel. The already restored ship changed owners again and began to bear the name Jahre Viking. In March 2004, ownership of it was transferred to First Olsen Tankers, which, due to the age of the structure, converted it into an FSO - a floating facility that was used only for loading and storing hydrocarbons in the Dubai shipyard area. After the last reconstruction, the tanker acquired the name Knock Nevis, under which it is known as the largest tanker in the world. After the last renaming, the vessel was towed in the role of FSO to Qatari waters to the Al Hashin field.

Knock Nevis Tanker Dimensions

The largest tanker in the world was named Knock Nevis. He became a kind of product scientific and technological revolution. As part of the design, a longitudinal hull framing system was used, and all superstructures were located at the stern. It was during the assembly of tankers that electric welding was first used. At different periods of its existence, the tanker was known as Jahre Viking and Happy Giant, Seawise Giant and Knock Nevis. Its length is 458.45 meters. To make a complete turn, the ship needed 2 kilometers of free space and the help of tugs. The transverse dimension of the water transport is 68.8 meters, which corresponds to the width of a football field. The ship's upper deck could easily accommodate 5.5 football fields. The tanker was withdrawn from the fleet on January 1, 2010; since then it has not only had no worthy competitor, but also simply no analogue.

The largest LNG tanker in the world

The largest LNG tanker is the ship called Mozah, which was commissioned to its customer in 2008. During construction, Samsung shipyards were used for Qatar Gas Transport Company. For three decades, LNG tankers have held no more than 140,000 cubic meters of liquefied gas. The giant Mozah broke all records with a capacity of 266,000 cubic meters. This volume is enough to provide heat and electricity to the entire territory of England for a day. The vessel's deadweight is 125,600 tons. Its length is 345 and its width is 50 meters. Draft - 12 meters. The distance from the keel to the hole corresponds to the height of a 20-story skyscraper. The design of the tanker included its own gas liquefaction unit, which minimized harmful fumes and almost completely eliminated the risk of an accident, ensuring 100% safety of the cargo. In the future, it is planned to design and launch a total of 14 vessels of this series.

The largest tankers in history

The largest tanker in the world is Chinese. As generations changed, so did the ships, which by now have already been decommissioned, but the country of origin remained the same.

There are only 6 ULCC class designs that managed to exceed the 500,000 dwt mark:

• Battilus with a deadweight of 553,662. Period of existence from 1976-1985.
• Bellamya with a deadweight of 553,662, sailed the oceans from 1976 to 1986.
• Pierre Guillaumat, designed in 1977 and decommissioned in 1983.
• Esso Atlantic with a deadweight of 516,000 and a lifespan from 1977 to 2002.
• Esso Pacific (516,000 tons). Operating period: from 1977 to 2002.
• Prairial (554,974 tons). Designed in 1979, withdrawn from flights in 2003.

That is, if it is able to transport, say, frozen chickens, it will be considered as a cargo vehicle.

Types

Bulk carriers

Bulk carrier- the general name of ships intended for the transportation of solid, bulk, and packaged cargo, including containers and liquid cargo in containers. Includes universal vessels for general cargo, equipped with loading and unloading facilities, vessels for the transportation of bulk cargo, bulk carriers with a deadweight of less than 12 thousand tons, and some other vessels, for example, sinter carriers.

Bulk carriers

Bulk carrier(Also bulker) - a vessel for transporting bulk cargo in bulk in the hold (that is, without containers). Bulk carriers are used for transporting ore, coal, cement, etc. In addition to universal bulk carriers, there are specialized ones equipped for transporting certain types of cargo, for example ore carriers, cement tankers, etc. There are ships capable of simultaneously transporting both bulk and liquid cargo (then there are those that are both a bulk carrier and a tanker), for example, oil ore carriers.

Container ships

Container ship- a vessel for transporting goods in standardized containers.

Roller skates

Roller(also: ro-ro vessel) - a vessel with a horizontal loading and unloading method. Ro-Ro carriers are most often used for transporting (trucks) cars and other wheeled vehicles. The main advantage of a ro-ro carrier is the speed of unloading and loading of the vessel. These operations do not require cranes: trucks with cargo they simply drive in/out onto the cargo decks of the ship along a ramp.

Lighter carriers

Lighter carrier- a vessel carrying special barges - lighters. Lighter carriers are often used where large vessels cannot approach the pier due to insufficient depth or for other reasons. The lighters are loaded at the pier, transported by tug to the lighter carrier and lifted aboard the lighter carrier. Unloading is done in reverse order. In Russia, there is the world’s only nuclear-powered lighter carrier, the Sevmorput, which serves the villages of the Arctic Ocean. This lighter carrier is part of the Federal State Unitary Enterprise Atomflot of the Rosatom State Corporation.

Tankers

Tanker is a vessel for transporting liquid cargo.

Reefer ship

Reefer ship is a ship whose holds are equipped with cooling units. Reefer ships are used to transport perishable food products. Because of this, they received the nickname “banana carriers” among sailors.

Classification by size

There is a worldwide classification of cargo ships by size. It relies on the capabilities of ports and terminals to receive ships of different sizes and on capacity the most important canals (Suez and Panama). There are several interpretations of these classes: Lloyd's scale, AFRA scale, flexible market scale.

Links

• Dry cargo ship // Great Soviet Encyclopedia: [in 30 volumes] / ch. ed. A. M. Prokhorov
• Dry cargo ship at glossary.ru

Notes

1. Cargo ship; Bulk carrier // Great Soviet Encyclopedia: [in 30 volumes] / ch. ed. A. M. Prokhorov. - 3rd ed. - M.: Soviet Encyclopedia, 1969-1978.

§ 57. TANKER CARGO DEVICE

The tanker's cargo structure consists of a pipeline system used to receive cargo, distribute it among cargo tanks and unload it, and pumps designed to pump cargo.

The pipelines are divided into cargo and stripping pipelines; for each pipeline system, separate pumps are installed. The cargo system consists of large diameter pipes (250-350 mm), allowing the cargo to be pumped using the full capacity of the cargo pumps until the cargo level in the tanks drops almost to the level of the pipeline intake openings, when the pump begins to “swallow” air. After this, the remaining relatively small amount of cargo is pumped out through the stripping system using stripping pumps, the productivity of which is significantly less than cargo pumps.

The cargo system is laid along the bottom of the cargo tanks, above the bottom set, and ends in the cargo pump room, connecting to the cargo pumps. One or more lines extend from the pumps to the upper deck, where they branch into branches extending to both sides and to the stern. Flexible hoses are attached to the extensions, connecting ship pipelines with onshore mains. Locking clinkets are installed at the ends of the extensions.

From the same line, vertically located pipes - risers - extend into the cargo tanks, which serve to receive cargo directly from the deck into the tanks, bypassing the pump room. Each riser serves not one, but a group of tanks. In each cargo tank, a branch with a receiver called a snorkel extends from the cargo line laid along the bottom. A clinker is installed on the extension, which has a rod outlet to the upper deck, ending in a flywheel. In addition to the receiving clinkets located in each tank, there are secant clinkets on the main line, separating a group (of two to three) tanks. In addition to the cargo, water ballast, which is necessary for the tanker during transits without cargo, is received and pumped out through the cargo line. On some tankers that have separate ballast tanks, a special ballast pipeline, similar in design to a cargo pipeline, is installed to pump ballast.

Oil tankers use numerous cargo piping systems. The most widespread are linear and ring systems, which create the greatest opportunities for cargo operations when transporting several types of cargo simultaneously.

The linear system on a tanker with two longitudinal bulkheads (Fig. 149) consists of several lines 1, 2 and 3, each of which has its own pump 4, 5 and 6 and serves one specific group of tanks. From each line, risers 7, 8 and 9 extend to the upper deck, connected to deck lines 10, 11 and 12. With such a system of cargo pipelines, the ship has the ability to simultaneously accept three types of cargo. To eliminate the possibility of mixing cargo, two clinkets are installed on the jumpers between the highways. In the event of a malfunction of one pump and to ensure that the pump can operate on “foreign” lines, the latter are connected to each other by jumpers 13 and 14, which also makes it possible to speed up the possibilities for cargo operations even with the same type of cargo.

With a ring system, along the bottom of the tanker (Fig. 150), which also has two longitudinal bulkheads, two lines are laid on the sides, connected by bow 1 and stern 2 transverse bridges into a ring. Receiving branches extend into each tank from both the left and right mains. To receive cargo, in addition to the pump room, risers are installed on the upper deck. Cargo pumps 3 and 4 can operate on both lines separately or together. The ring system also provides the ability to transport two or more types of cargo, since there are several secant clinkets on the highways.

Ring systems can also be made in a slightly different form, for example, on ships with one longitudinal bulkhead, and also depending on the requirements for the ship.

The stripping line is located in the cargo tanks similarly to the cargo line; it is also equipped with receiving clinkers in each tank, flywheels are located on the upper deck, and secant clinkers are installed. For the stripping line, pipes with a diameter of 100-150 mm are used. The stripping line in the pump room is connected to stripping pumps, the pressure line from which does not go out to the upper deck, but cuts into the cargo line, and sometimes, in addition, has a branch into the end cargo tank to collect the residues being stripped.

Stripping lines are usually laid using the same systems as the cargo lines. The flywheels of the clinkets located on the upper deck for quick orientation differ from each other in size and color. For example, all the flywheels of the stripping system are smaller in diameter than the flywheels of the load system. The flywheels of the tanks on the right side are painted green, those on the left side are painted red, the secant ones are painted black, etc.

In the cargo pump room, the cargo, stripping and ballast lines are interconnected, forming a complex pipeline system with a large number of clinkets. which allows cargo operations to be carried out in various options. To receive and pump out sea water, bottom seawalls are installed in the cargo pump room.

Cargo pump rooms can be located both in the middle and in the stern parts of the vessel. Some large tankers have two pump rooms. When the pump room is located aft, it is located between the cargo tanks and the engine room.

Preparing the tanker to receive cargo. One of the main requirements when transporting bulk cargo is to ensure that the quality of the transported cargo is maintained. Before accepting the cargo
tanks must be cleaned of silt, dirt that gets into the tanks along with ballast water, and rust that has fallen off the sides. This work is also carried out if homogeneous petroleum products were previously transported. When transporting fuel oil and crude oil, you should only remove dirt and solid residues that settle on the bottom.

Cargo tanks are usually prepared during ballast passages when en route to the loading port. Tanks are washed and cleaned one by one. If there are separators on the ship, washing water is passed through them, and the separated residues are collected in tanks for delivery ashore. To improve working conditions, the tanks are equipped with fans, and air is sucked through the cargo pipeline from the bottom of the tank. Ventilation is carried out at night, when tank washing stops.

All clinkets of the cargo and stripping lines must be checked for density by the water pressure in the pipeline created by the pump. All leaks noticed in connections and wedges must be eliminated. The density is checked immediately after washing the tanks and the pipelines themselves. If tanks have cargo heating coils, these should also be inspected for defects that could allow cargo to penetrate the coils. If cargo of several grades is accepted, then the transverse and longitudinal bulkheads separating the different grades must also be checked for water tightness.

Immediately before loading, all tanks are inspected and any foreign objects found are removed from the tanks. When carrying out cleaning work, non-sparking tools (shovels, scoops, buckets, scoops) must be used. All fire safety measures must be taken (grounding washing hoses, prohibiting the use of shoes with metal nails, taking into account the possibility of sparks from static electricity).

Cargo samples. The quality of petroleum products transported in bulk in cargo tanks may decrease due to the ingress of water, mechanical impurities in the form of dirt or silt, as well as mixtures with other petroleum products. To protect the interests of the shipowner and to prove that the transported petroleum products upon delivery were of the same quality as during loading, cargo samples are periodically taken during the latter.

At certain intervals (1-2 hours), cargo samples are taken from the discharge valve of the onshore pipeline at the side of the vessel. At the end of loading, all samples are mixed and the mixture is poured into two vessels with a capacity of about 1 liter each, which are sealed and stored for the required time - one at the sender of the cargo, the other on the ship. Such samples are taken separately for each type of cargo. If presented
the recipient of claims regarding the quality of the transported cargo, it is determined by the arbitrator by comparing control samples taken during loading with samples taken during unloading.

Water test. When the cargo is received, it may contain water that has got there from onshore tanks or from ship pipelines, in which it may remain after washing tanks or pumping out ballast. The presence of water in the cargo and its quantity are determined using water-sensitive paste or paper. The weight, attached to the measuring tape, which is used to measure the height of the level of the load in the tank, has a small groove, or flat, onto which paste is applied. If paper is used, it is simply attached to the weight. The tape measure is lowered into the tank through the measuring tube and when the weight reaches the bottom of the tank, it is held for some time necessary for the paste to dissolve with water. Having raised the tape with the weight, they notice the height reading at the boundary of paste dissolution on the weight and, using calibration tables, determine the volume of water, which is then excluded from the volume of the load.

Cargo measurements. Upon completion of loading, measurements are taken to determine the weight of the accepted cargo. The level of cargo in each tank can be measured with a metal measuring tape, graduated in centimeters, lowered into the measuring tube. After the weight suspended at the end of the tape measure touches the bottom, the tape measure is raised and a reading is noted based on the level of wetting of the tape that corresponds to the height of the load level in the tank with an accuracy of fractions of a centimeter. To speed up the measurement process, which is especially necessary at the end of loading, instead of a tape measure, a metro rod is used - a wooden slatted length

1.5-2.5 m with a crossbar in the upper part and having the same graduation along the entire length as a tape measure. The metro rod is quickly lowered until it stops with the crossbar into the measuring tube or into the inspection neck. Noticing the level of wetting of the foot rod, note the height of the void in the tank from the level of the load to the conventional point - the stop of the cross.

To determine the volumetric amount of cargo in the tanks on the ship, there are calibration tables, with the help of which, based on the measurements of the level of cargo or emptiness in the tank, the number of cubic meters of cargo is determined. By introducing amendments to specific gravity of the cargo, its temperature and the trim of the vessel, the weight of the cargo in tons is obtained, which is entered into the cargo documents.

Unloading. Preparatory work for unloading must be carried out before the vessel arrives at the port. If viscous petroleum products are transported, then a certain time before arriving at the port they need to be heated using standard steam heating coils located on the bottom of the tanks. It is necessary to prepare the necessary equipment - pallets, adapters, mats, rags, etc.
Upon arrival at the unloading port, all outboard scuppers on the cargo deck are closed with specially made wooden plugs. After completion of mooring on the ship, in the presence of representatives of the cargo recipient and the quality inspector, cargo samples are taken and its quantity is measured.

Unloading from tanks is carried out in the order specified in the unloading plan drawn up by the cargo assistant and approved by the captain of the vessel.

The responsibilities of the watchman during unloading include: opening and closing the clinkers on the upper deck as directed by the cargo assistant; measurement of voids; monitoring the position of the cargo level in tanks for timely switching of cargo pumps to stripping pumps; monitoring the absence of possible leaks from flange connections of pipelines and drain valves, etc.

During unloading, the ship rises in relation to the berth, so the sailor must monitor the condition of the cargo hoses, preventing them from rubbing against the protruding parts of the ship’s hull, and also promptly remove the mooring cables.

Upon completion of unloading and cleaning of the tanks, the recipient’s representative, together with the cargo assistant, makes sure that there is no cargo in each tank, taking measurements using a tape measure, as well as visually using an explosion-proof electric flashlight.

In some cases, cargo operations, such as supplying fuel to other ships, can be carried out at sea both while underway and while the ships are drifting. When transferring cargo underway, the vessel receiving the cargo or bunker is towed by the tanker astern. Then, from the tanker, with the help of a conductor, a hose is transferred to the towed vessel, where it is connected to the receiving line.

Unloading can also be carried out at a time when the vessels, without moving, are moored side by side. Such an operation can be successfully carried out without the use of special large soft fenders only in the complete absence of waves, which happens extremely rarely in the open sea or ocean. Even slight disturbances cause motion, during which ships standing side by side can easily get damaged to their hulls and superstructures. To avoid damage, it is necessary to use large fenders, which must be made either specially, as is done for fishing floating bases, or from auxiliary material - logs, old car tires, etc. In the practice of whaling fleets, carcasses of killed animals are used as fenders whales

The mooring ends of ships moored in the sea are always subject to strong jerks due to uneven movements of ships in rough seas, which often leads to cable breaks. To avoid this, it is recommended to use synthetic cables or combined cables - steel with a synthetic cable spring. It is not recommended to feed short cables, as they quickly break.

To successfully carry out the transfer of liquid cargo or fuel at sea, which is a complex operation, the coordinated actions of the entire crew are required.

Management of cargo operations on a tanker and their mechanization. Cargo operations on tankers, due to the explosiveness of the cargo being transported, create a number of specific conditions. For example, cargo and stripping pumps are located in the cargo pump room, and their drives, both electric motors and steam turbines, are located behind a tight bulkhead in the engine room. Therefore, to control the pump drives, a control panel is installed in the area of ​​the pump room at the level of the transition bridge. To avoid overly complex designs, especially for steam drives, starting the pumps from the remote control is not provided. This operation is performed by the driver on duty in the engine room according to orders transmitted from the console via telephone or speaking tube. For the same purpose, on some ships a telegraph is installed in the cargo pump room, through which the necessary orders are transmitted to the engine room.

The console contains the necessary instruments - pressure gauges, vacuum gauges and others used to monitor the operation of the pumps. Changing the speed of the pumps, as well as stopping them, can be done from the remote control. For an emergency stop of the pumps, for example, in the event of a hose break or cargo overflow, an emergency pump stop button is installed, usually in the area of ​​the ladder, where the sailor on watch is constantly located.

Measuring the level of cargo on modern large tankers with 30-40 cargo tanks, and the operations of opening and closing a large number of clinkers when moving from one tank to another, are very labor-intensive. In some cases, for example, at the end of loading, as a result, it is necessary to reduce the loading speed, for fear of overloading the cargo, since actions with large cross-section clinkers and a large number of flywheel revolutions manually are limited by human capabilities. However, despite the apparent simplicity of mechanization of relatively simple processes - manipulation of clinkers and measuring levels, these works have not yet been translated into a convenient, reliable and simple mechanized system. The main obstacle to this is the lack of an explosion-proof remote system for measuring the level of cargo in tanks, which would provide reliable readings with the required constant accuracy. However, on some tankers these
the work is still mechanized, although the performance of these systems does not reach the required level of accuracy.

On a vessel equipped with such systems, cargo operations can be performed by one person - an operator at the central control panel. All clinkers, cargo, stripping and cutting, located both in tanks and in the cargo pump room, have a hydraulic drive located directly on the clinket body and are controlled from a remote control by simply pressing a button. The remote control has indicators for the clinker positions “open - closed”. From the same console, all pumps are remotely controlled and the operation of their drives is monitored. Cargo levels are also measured remotely using a pneumatic gauge system that converts the pressure of the height of the liquid column in the tank into an electrical impulse transmitted to the central control station. A device that converts the air pressure signal into an electrical one is installed outside the tank in a safe place.

Such a system does not have the accuracy necessary to calculate the amount of cargo received and gives an approximate reading of the level. To accurately determine the amount of cargo received, it is necessary to measure voids manually.

The mechanization of cargo operations should not only improve the operational performance of the vessel, reducing docking time, but also significantly facilitate the work of the crew and create the prerequisites for the comprehensive mechanization of ship operations and reducing the number of crew.

Protection of tanks from corrosion. The surfaces of cargo tanks and the equipment located in them (pipelines, clinkers, rods, ladders, etc.) when transporting light petroleum products (gasoline, kerosene, naphtha, etc.), as well as crude oil, especially with a high sulfur content connections are subject to severe corrosion. During ballast passages, which sometimes take up to 50% of the operating time, salty sea water is taken into the cargo tanks for ballast, which also contributes to the rapid oxidation of steel.

The pipelines through which liquids are pumped from high speed. The resulting electrochemical processes also contribute to the formation of general corrosion or individual, deep local lesions and fistulas. As a result, after four to six years of operation, a significant part of the pipelines requires replacement, with the tanker being taken out for repairs for a considerable period of time.

To protect the internal surfaces of cargo tanks from corrosion, protective coatings are applied to all surfaces in the form of a paint film, as well as electrochemical protection.
For painting, various compositions are used that are resistant to petroleum products, made on the basis of ethinol varnishes, epoxy and vinyl resins and many other chemical compounds. The application of protective coatings, however, poses a number of difficulties, since most of them are toxic and require the use of special protective devices and intensive ventilation. The vapors of these paints are explosive and require careful implementation of all fire safety measures. In addition, to ensure the strength of the coating and its good adhesion - sticking to the metal - its surface must be very thoroughly cleaned.

The best results are obtained by treating all surfaces with sandblasting or shot blasting machines. Therefore, the application of protective films, as well as the correction of local damage, can only be carried out in the factory during the construction of the vessel or its repair.

A tread system is used as electrochemical protection. It consists of protectors - castings from magnesium or aluminum-magnesium alloys in the form of disks or cones, evenly placed in close proximity to the internal surfaces of the tank. Having a reduced potential with respect to steel and being in salt water during ballast transitions, which in this case is an electrolyte, the magnesium electrode begins to work as a cathode, the particles of which are transferred to the surface of the steel, creating on it protective film. The protector itself is destroyed.

It should be borne in mind that aluminum-magnesium alloys, when struck against corroded steel, cause a spark, so the fall of such a protector in a non-degassed tank can lead to an explosion. This property significantly limits the use of tread protection on tankers.

To protect tanks from corrosion, inhibitors are also used - special chemicals that are introduced into the transported cargo, and they settle on the surface of the tank, creating a protective film.

Measures to prevent sea pollution from petroleum products. On modern transport ships, the mechanisms and boilers of which operate on diesel fuels and fuel oils inevitably generate waste oil products, accumulating in the bilges of engine rooms and tanks for collecting dirty and waste oils. A large number of oil tankers carry out tank cleaning work during ballast passages, as a result of which a large amount of water is heavily contaminated with oil products. Pumping overboard bilge water, and especially washing water, from tankers creates a serious

pollution threat sea ​​water petroleum products, leading to the death of fish, birds and marine animals, as well as oil pollution of seashores, beaches, canals, rivers and ports.

Therefore, back in the twenties of our century, this issue began to be seriously studied in order to create effective measures to combat sea pollution with oil products. Various recommendations have been developed. However, the first document was the Resolution of the International Convention for the Prevention of Marine Pollution by Oil, adopted in 1954.

In subsequent years after the adoption of this Convention, practice showed the need for additional measures to prevent the discharge of oil from seagoing vessels. To this end, the Intergovernmental Maritime Consultative Organization (IMCO) convened International conference on the Prevention of Marine Pollution by Oil, which took place in London in the spring of 1962. The Conference significantly revised the 1954 Convention, supplemented it, and clarified the scope of application, norms and requirements.

The conference resolutions state that the only known and fully effective method of preventing oil pollution of the sea is a complete ban on the discharge of persistent oil into the sea. However, before completely banning the discharge of oil into the sea, it is necessary to equip ships with appropriate devices for receiving oil-contaminated ballast from them.

Therefore, the Convention did not set a date for a complete ban on the discharge of polluted waters into the sea, but established exclusion zones as a temporary measure. Oil-contaminated water can be pumped overboard within these zones only through devices that ensure water purification until the oil content does not exceed 100 mg per 1 liter of mixture. In the absence of such devices on the ship, contaminated water must be pumped outside the prohibited areas or upon the ship's arrival at the port into special containers.

Each ship is required to keep a special log, which records the time and place of draining contaminated water, receiving and discharging ballast water, washing cargo tanks, etc.

The Soviet Union has developed a whole range of organizational and technical measures to combat marine pollution with oil products. In April 1961, the Ministry navy The “Temporary Instructions for the Prevention of Marine Pollution by Oil”, prepared taking into account the basic requirements of the 1954 Convention, were put into effect, control over the implementation of which was entrusted to port captains.

In September 1968, the Council of Ministers of the USSR adopted a resolution “On measures to prevent pollution of the Caspian Sea.”
Transportation of bulk and other cargo by tankers. In addition to petroleum products, tankers also transport other cargoes in bulk, such as vegetable edible oils, alcohols, molasses, ammonia, liquefied gases etc. Transportation of products such as vegetable oils, alcohols or molasses, does not require special devices and equipment. It is only necessary to thoroughly rinse and ventilate the tanks, since one of the main requirements for cargo tanks is the cleanliness of their surfaces and the absence of odors. Some edible oils, such as coconut oil and molasses, have a high pour point and must be heated before unloading. It must be borne in mind that each product has its own heating temperature, exceeding which leads to a loss of cargo quality.

Sometimes raw sugar is also transported on tankers.

Bulk grain cargo is transported on tankers relatively often. Preparing tanks for grain transportation also involves thoroughly washing and ventilating the tanks until oil odors are eliminated. In order to prevent grain from getting into the pipelines, the receiving snorkels of the cargo and stripping lines must be carefully tied with canvas. If the voyage involves a transition from one climatic zone to another, with a sharp change in water and air temperatures, at which the internal surfaces of the tanks begin to sweat, then to protect the cargo from moisture, all surfaces of the bottom and sides must be covered with insulating material before loading, sometimes even in several layers. Straw mats have good insulating properties, but burlap or canvas can also be used.

For the transportation of liquefied gases, specialized tankers are used, adapted for the transportation and loading and unloading of liquids under relatively high pressure.

Oil and its products are transported, including by sea, using special ships that fall into the category of tankers. Oil tankers are real monsters of the commercial fleet, having received the status of world record holders in terms of their dimensions and carrying capacity.

Design features of tankers

At the present stage of shipbuilding, an oil tanker is a single-deck vessel with built-in tanks (tanks), capable of transporting hundreds of thousands of tons of cargo. The world's first self-propelled oil tanker, the Zoroaster, had much more modest characteristics and could transport a maximum of 250 tons of raw materials.

Zoroaster was built in Sweden by order of the Russian company Nobel Brothers Oil Production Partnership. The ship went to sea in 1877. Before its construction, conventional sailing ships were used to transport oil throughout the world, with the cargo being poured into wooden barrels.

Nowadays, the hulls of tankers, like most other ships, are built on the basis of a frame to which a metal skin is attached. The specificity is that inside the tanker hull is divided into several tank compartments - tanks, which are filled with oil and petroleum products during loading. The volume of one such tank is at least 600 cubic meters, in large-tonnage ships - more than 10 thousand cubic meters.

Tanker projects that were developed until the seventies provided for the construction of three-axle ships with a mid-structure with a wheelhouse, an extended poop and a forecastle. Now tankers are produced without a middle superstructure. Living quarters and control stations are located on the poop deck of increased height.

Cargo spaces occupy up to 70% of the ship's length. The number of additional longitudinal bulkheads in the tank sector reaches two or three units. Bulkheads are installed to prevent cargo from spilling over. Currently, all tankers with a carrying capacity of more than a thousand tons are equipped with heaters for high-viscosity oil or solidifying raw materials, powered by steam, electricity or the heat of gases from the ship’s engines.

Tanker projects provide for the implementation of modern shipbuilding solutions - installation of bow and stern thrusters, adjustable pitch propellers, systems remote control operation of power plants and cargo operations.

Operational safety

To a large extent, the design features of tankers are influenced by the safety requirements for the transportation of oil cargo. Since 1996, under the terms of the International Maritime Organization (IMO), tankers have been equipped with double hulls, and the volume of tanks is also limited.

On the one hand, compliance with such requirements makes it possible to reduce the threat of pollution marine environment, on the other hand, it makes the hull heavier, which ultimately leads to the inexpediency of building ships with a deadweight above 450 thousand tons. One of the newest popular concepts for building a tanker with a high degree of safety and reliability involves a design with dual systems - not only the hull, but also two engines, engine rooms, propellers and rudders.

In order to ensure fire safety the space of the tanks that is not occupied by oil is filled with inert gases. If a fire does occur, steam and foam are supplied to the tanks to extinguish the fire. A number of ship models provide for fire extinguishing by supplying oxygen-poor engine exhaust gases to the fire zone.

Due to the fact that a number of petroleum products, including their vapors, have penetrating properties, the cargo compartments are separated from the remaining modules of the ship by special control compartments - meter-long vertical cofferdams.

If the tanker has a middle superstructure, it is also separated from the tanks by a two-meter horizontal compartment. The safety compartments are constantly open and ventilated. They are used as storage areas for loading hoses.

To prevent accumulation petroleum gases There is no double bottom in cargo areas. However, such a design solution does not affect the high level of unsinkability of tankers, since their hulls are equipped with a large number of bulkheads, and the tanks are hermetically sealed. Storage facilities for fuel and water supplies are located at the end parts of the hull, including in the double bottom area of ​​the engine room.

Despite serious design solutions to ensure the safe operation of tankers, emergency incidents still happen to them - both due to breakdowns and crew errors. Let us recall recent cases: in December 2016, due to a tanker malfunction, traffic through the Bosphorus Strait was blocked, and in February of this year, a tanker from Panama ran aground.

How tankers are loaded with oil

Tankers are loaded using oil loading complexes. The construction of oil berths started at the beginning of the last century, which was associated with the rapid development of the tanker fleet and the laying of oil pipelines. The first oil loading pier in Russia was built in Batumi in 1906. Through its facilities, kerosene was loaded onto ships.

Modern berths are deep-water and provide loading and accounting of raw materials, bunkering and other operations with tankers in automatic mode. The infrastructure of the berth complexes includes stands, metering units, safety, control and shut-off valves, units for preventing accidents during loading and fire extinguishing systems.

With the help of pumping units, oil and its refined products are pumped through pipeline systems, including underwater ones, to fixed or floating oil loading berths, after which they are delivered to the tanker. In turn, the ship is unloaded using ship pumps through pipelines laid in tanks or along the deck. Raw materials are pumped out of tanker tanks and delivered to the tanks of sea and river transshipment points and bases, which include berths.

When empty (without cargo), water ballast is pumped into the ships' tanks. Before receiving cargo, it is moved to port treatment facilities or oil depots. There are tankers (such modifications were also built in the USSR), the design of which provides for the presence of ballast tanks between the double hulls. This solution allows not to pollute ballast water with petroleum products. At the same time, ballast water does not require treatment before discharge.

Classification of oil tankers

Tankers are classified according to various criteria, including deadweight (carrying capacity), dimensions and draft. Deadweight division is a specialized classification of oil tankers that applies only to that class of vessel.

According to deadweight, tankers are divided into categories:

1. General Purpose (GP) - small-tonnage and general purpose tankers, designed to transport from 6 thousand to 24.999 thousand tons of oil or petroleum products, including bitumen.
2. Medium Range (MR) - medium-tonnage (from 25 thousand to 44.999 thousand tons).
3. Large/Long Range1 (LR1) - large-tonnage first class (from 45 thousand to 79.999 thousand tons).
4. Large/Long Range2 (LR2) - large-tonnage second class (from 80 thousand to 159.999 thousand tons).
5. Very Large Crude Carrier (VLCC) - large-capacity tankers of class 3 (from 160 thousand to 320 thousand tons).
6. Ultra Large Crude Carrier (ULCC) - supertankers with a deadweight of 320 thousand tons, which are used to transport oil produced in the Middle East and in the Gulf of Mexico.
7. Floating Storage and Offloading unit (FSO) - supertankers with a deadweight of more than 320 thousand tons, used only for unloading raw materials at sea onto tankers of smaller classes.

Classification by size and draft is carried out according to the criterion of the possibility of tankers passing through straits, canals, other water bodies and hydraulic structures. This classification applies not only to tankers, but also to other types of vessels.

Tankers are classified according to their dimensions and draft as follows:

1. Seawaymax - can pass through the North American St. Lawrence Seaway.
2. Panamax are capable of passing through the Panama Canal.
3. Aframax are designed for use in the Black Sea, Mediterranean waters, East China and Caribbean Seas, on canals and in ports that are unable to accommodate tankers of a larger class.
4. Suezmax is a class assigned only to oil tankers and designates their ability to pass through the Suez Canal.
5. Malaccamax tankers transport oil from the Persian Gulf to China, passing through the Strait of Malacca between Malaysia and Indonesia. The draft limit reaches 25 meters.
6. Post-Malaccamax, whose draft is greater than that of ships of the previous class, is forced to set a course for China through the deep-water Lombok Strait (Indonesia).
7. The Capesize class includes tankers of the VLCC and ULCC categories, which due to their size are not able to pass through the Panama and Suez Canals. They follow routes along Cape Horn (Chile) or the Cape of Good Hope (South Africa).

Giant tankers

Among the tankers, which, due to their impressive dimensions, are real giant ships, have their own record holders. The most famous representative of supertankers was the ULCC class vessel Knock Nevis (at various times also called Jahre Viking, Happy Giant, Seawise Giant and Mont), which changed several owners during its operation.

Knock Nevis is still considered the largest ship in human history in terms of deadweight - 564.763 thousand tons. The length of the tanker was 458.45 meters, the braking distance exceeded ten kilometers. When fully loaded, the tanker's draft did not allow it to pass through the Pas de Calais Strait (English Channel) and the Suez Canal. In addition, due to its size, the ship was not able to pass through the Panama Canal.

The ship was built by the Japanese company Oppama and commissioned in 1976. Before the conversion, the length of the tanker was 376.7 meters, deadweight - 418.610 thousand tons. Three years later, after changing ownership to the Hong Kong corporation Orient Overseas Line, it underwent restructuring, during which the deadweight was increased by almost 150 thousand tons. After modernization, the tanker acquired the status of the largest ship on the planet.

The ship was cruising around the Cape of Good Hope, carrying oil from Middle Eastern countries to the United States. In May 1986, while Iran and Iraq were at war, Knock Nevis was attacked by an Iranian fighter in the Strait of Hormuz. A fire broke out and three people died. The tanker ran aground. It was raised and restored by the Norwegian company Norman International only two years later.

After tankers without a double hull were banned from entering American and European ports, the vessel’s transport “career” ended and it was used as an oil storage facility in the Qatari Al Shaheed field. The ship made its last voyage to the coast of India, where during 2010 it was cut into metal due to the end of its service life. Only one of the 36-ton anchors remained from the tanker, which became an exhibit at the Hong Kong Maritime Museum.

However, a number of experts question the title of Knock Nevis record holder, assigning the status not only to large tanker, but also the largest ship launched in the same year, the ULCC Batillus class oil tanker. The fact is that Knock Nevis received its outstanding characteristics only after restructuring. Batillus, according to the project, initially had a length of 414.22 meters and a deadweight of 553.662 thousand tons. Thus, immediately after leaving the stocks, it outperformed the Knock Nevis. The tanker was built by the French company Chantiers de l’Atlantique for Shell (UK-Netherlands).

Since launch, Batillus has completed 25 voyages, mostly from the Persian Gulf to Northern Europe. The tanker has been idle in ports for a long time more than once. The company's management was not satisfied with the low frequency of flights and in 1985 decided to sell the tanker for scrapping. The ship was scrapped in Taiwan that same year.

After the dismantling of the largest tankers Knock Nevis and Batillus, the status of the largest operating ships of this type passed to four ULCC-class vessels of the same type - TI Oceania, TI Asia, TI Africa and TI Europe, built by the South Korean Daewoo Heavy as part of the Hellespont project in 2002–2004 years.

These ships have a deadweight of 441.585 thousand tons and a hull length of 380 meters. The owner of TI Oceania and TI Africa (original names Hellespont Fairfax and Hellespont Tapa, respectively) was the Canadian shipping company Shipholding Group, and TI Asia and TI Europe (Hellespont Alhambra and Hellespont Metropolis, respectively) were acquired by the Euronav operator (Belgium).

The tanker industry operates efficiently and earns money not only thanks to its large transport capabilities, but also to established traditions and even some tricks. Transportation on oil tankers, like any other major economic sector, has impressive indicators and its own unique features:

• The tanker fleet accounts for a third of the world's merchant shipping tonnage. The total carrying capacity of tankers reaches 489 million tons. There are currently 9,435 tankers of various classes worldwide.
• Due to the low cost of freight, oil transportation by sea is characterized by high economic efficiency. This transportation scheme is inferior in this criterion only to the supply of raw materials through pipelines.
• The vast majority of tanker owners are companies from Greece. The same is true for the commercial fleet as a whole. The tanker shipping market is extremely opaque, with operators often resorting to “flag of convenience” schemes (usually Malta, the Bahamas and Marshall Islands, Liberia or Panama).
• Environmental threats during transportation by tankers are practically absent due to the high degree of safety and technological excellence of the vessels.
• The main risks of the industry are related to geopolitics. Ships have to pass through canals and straits, the closure of which can not only disrupt contracts, but also affect the price of oil. Thus, in the event of a conflict between Saudi Arabia and Iran, the movement of tankers through the Strait of Hormuz may be stopped. Currently, up to 17 million barrels of “black gold” are transported along this route per day. Another example is that closing the Strait of Malacca will completely deprive China of oil delivered by sea.
• IN last years The trend of oil companies using tankers as storage facilities for raw materials in anticipation of a more favorable market situation is gaining momentum. Now they simultaneously store up to 180 million barrels of oil, which is more than double the 2014 figure. There are up to four hundred storage tankers in the ports of Singapore.
• Crews, when carrying out illegal operations related to the illegal transfer of oil at sea to other ships (as the Iranians did during international sanctions), turn off transponders, which makes it possible to hide the location and draft of the offending tankers, that is, essentially making data on the change inaccessible the weight of their cargo. Such ships have to be tracked using alternative methods, including satellite imagery. Pronedra wrote earlier that Iran, in particular, sells oil directly from tankers.
• The degree of automation of modern tankers is so high that even the largest vessels of this type can be operated by one person. Supertanker captains are secretly considered to be among the maritime elite.
• To prevent heating and evaporation of cargo, the exterior of the deck of oil tankers is sometimes painted white, but to prevent harmful effects To protect the crew's vision of bright reflected light, sailors are given sunglasses.
• The average service life of a supertanker is 40 years.

Tanker transportation is not just a separate segment of oil logistics, but also a powerful independent economic sector, a whole world of leisurely steel giants that deliver colossal volumes of “black gold” to different parts of the globe. The contribution of shipbuilders who create tankers is not only to the development of the oil business and the commodity market, but also to the progress of engineering, the improvement of maritime transport system and the increase in the degree of environmental safety is difficult to overestimate.