Lyntas/mining_domain_knowledge_reference_dataset huggingface dataset:
Area: Oil Tanker & Ship Building
COW Lines (Crude Oil Washing)
On the main deck you will find the cow main line with branches leading to the ships crude oil washing machines. This line comes from the cow cross over line on the delivery side in the pump room.
Area: Oil Tanker & Ship Building
Inert Lines
To control the atmosphere in the cargo tanks you will find inert lines on the main deck leading to each tank. These lines are for supplying inert gas during discharging or tank washing. Some inert gas systems are connected to a main riser, which are fitted with a press/vacuum valve for regulation of the pressure and vacuum in the cargo tanks. Other inert gas systems have these press/vacuum valves installed on each cargo tank with the same function as the riser.
Area: Oil Tanker & Ship Building
Cargo heating
In addition to the provision of cargo compartments, pipelines and pumps for handling the oil, the oil tanker must also provide adequate heating systems for some types of oil and cooling systems for others. Properly constructed ventilation systems are necessary in all oil tankers in order to avoid excessive loss of cargo from evaporation and to control the escape of dangerous gases.
Steam is used to heat the oil in a ship's tank. It is piped from the boilers along the length of the vessel's deck.
In ships carrying heavy lubricating oils which require heating, the coils are generally ordinary steel pipe, but vessels carrying crude oils which have to be heated, are now equipped with cast iron or alloy coils.
Area: Oil Tanker & Ship Building
Ventilation
Cargo pump rooms shall be mechanically ventilated and discharges from the exhaust fans shall be led to a safe place on the open deck. The ventilation of these rooms shall have sufficient capacity to minimize the possibility of accumulation of flammable vapours.
Area: Oil Tanker & Ship Building
Gas freeing
It is generally recognized that tank cleaning and gas freeing is the most hazardous period of tanker operations. This is true whether washing for clean ballast, gas freeing for entry, or gas freeing for hot work.
Area: Oil Tanker & Ship Building
Oil Tankers
Based on size, oil tankers have been categorised into the following types:
1.Small Range (Product) Tanker: 10,000 to 60,000 tons DWT.
2.Panamax Tanker: 60,000 to 78,000 tons DWT.
3.Aframax (Average Freight Rate Assessment) Tanker: 80,000 to 1,20,000 tons DWT.
4.Suezmax Tanker: 1,20,000 to 2,00,000 tons DWT.
5.VLCC (Very Large Crude Carrier): 2,00,000 to 3,20,000 DWT.
6.ULCC (Ultra Large Crude Carrier): 3,20,000 to 5,50,000 DWT.
Area: Oil Tanker & Ship Building
The most important design drawing that is to be studied in order to identify the design of a ship, is its General Arrangement Drawing. Figure 3 illustrates the profile view of an oil tankers general arrangement. It basically shows the arrangement of all the spaces within the ship, and gives a frame-by-frame location of every space, bulkheads, and other primary structures
The main deck of an oil tanker is usually mounted with a network of pipelines that are used to load and unload cargo oil to and from the ship. Flexible hoses are attached to the pipelines for completion of the process.
The engine room and superstructure, as usual, are located at the aft. But, one notable feature in oil tankers, that is not found in other types of ships is the pump room, that is usually located just forward of the engine room. The pump room houses all the pumps required for cargo oil loading and discharge.
Area: Oil Tanker & Ship Building
Bulbous Bow:
Today, all tankers are equipped with a bulbous bow, so as to increase the power efficiency of the ship. Though these are slow speed ships, a bulbous bow reduces the wave making resistance considerably.
Area: Oil Tanker & Ship Building
Structural Design:
The structural design of oil tankers vary according to the type and size of the tanker. To understand them, we will study their midship sections in detail.
Area: Oil Tanker & Ship Building
Double Hull Tankers:
All oil tankers of length above 120 m are required to be double hulled, as per MARPOL rules. Panamax, Aframax, Suezmax, VLCC and ULCC tankers are all double-hulled. The primary reason for providing two hulls is to prevent the contact of cargo oil with the external environment in case of any structural damage to the hull.
Today, irrespective of the classification society certifying the design of a tanker, the structural design of double hull tankers is done according to The Harmonised Common Structural Rules (CSR) for Tankers, by IACS.
Area: Oil Tanker & Ship Building
Power and Propulsion:
Since tankers are low speed vessels (average maximum cruising speed is 15.5 knots), and are not restricted by space constraints, they can afford to be run by large slow speed marine diesel engines. These engines occupy more space than high speed marine diesel engines, but provided more shaft efficiency, and gearbox losses are eradicated since the RPM of the engine is same as that of the propeller. Usually, large diameter and low RPM propellers are used for more propulsive efficiency.
Area: Oil Tanker & Ship Building
Systems On-board: 
Oil tankers have a number of systems that are unique to its operation. We will discuss the most important ones in brief.
Cargo Oil Heating System: Ships carrying crude oil are equipped with this system, as crude oil is heavy and becomes very sluggish and thick in cold environments, which can block the pumps and pipelines during discharge. So, cargo oil heating system is used to maintain the suitable temperatures and viscosity of cargo oil in holds.
Cargo Tank Venting System: Did you know that cargo oil tanks are never pressed full so as to allow space for oil vapour? But, at the same time, these vapours, being highly inflammable, are not allowed to accumulate in the cargo tanks. Proper venting systems allow the vapours to escape from enclosed spaces.
Overflow Control System: This system uses a level and pressure cascade control to ensure that the level of oil in the tank does not exceed the design head. High level alarms and spill valves are connected to the system in order to take correct action in case of anomaly.
Inert Gas System: The space between the free surface of the cargo oil and the top plating of the tank is to be kept inert, in order to prevent access of oxygen, so that even in case of any accumulation of oil vapour, a situation of fire is avoided. This is done by continuous supply and regulation of inert gas in cargo oil tanks. The space above the oil surface is ensured to be completely occupied by inert gas. The most common gases used for this purpose are Argon and Carbon-dioxide.
Fire Fighting System: The fire-fighting systems on board an oil tanker is the most vital for the ships safety, and is designed as per the MARPOL rules. Fire hoses, extinguishers and sprinklers are distributed along the ships length and breadth for access to all points. CO2 bottle room just above the engine room to allow CO2 flooding in the engine room during engine room fire.
Most oil tankers are provided with at least one deck-crane so as to handle the cargo oil hoses during discharge and loading of cargo oil, when the hoses are to be removed from stowage points and connected to the discharge manifolds on the ships deck.