Company SMS states that the cargo plan should be signed by all the ship's crew involved in. The means and means of communication between the ship and the shore should be established and the procedures should be discussed and agreed.
Cargo Operation
Cargo Loading Cargo Unloading
The floating dome system also allows the mooring of the vessel as well as the transfer of oil from the bow to the collector in the middle of the ship. When ships are moored in a harbor or wharf, oil cargo is usually transferred using an articulated arm.
Cargo Loading
During loading, as far as practicable, pitch and trim should be adjusted with the aid of the load. Any discrepancy in the records should be investigated and the discrepancy reported to the Chief Officer.
Cargo Unloading
Once the drop lines are closed, the cargo begins to move to the manifold and to the terminal. As the cargo passes through the manifold, the deck watchman must secure the manifold. The deck watch must continuously check for oil leaks in the cargo space during the unloading of the oil.
If the cargo pump draws gas or air into the suction instead of liquid, then the pump will operate in a partial vacuum instead of the liquid. Once the cargo operation is completed from ship and walk side, the manifold gate valve must be closed. After completion of the cargo operation, port ports, vapor locks and all other tank openings must be closed.
Stripping
This is because, as the pump is a positive displacement pump, it can develop enormous pressure in the discharge line. All the lower and upper crossovers must be kept open to strip pump housings, separators, drains. Finally, as the cargo lines are stripped, the pump can be slowly stopped and the steam to the system can be shut off.
Therefore, to increase the pump driving pressure, the system pressure must first be increased and then the pump driving pressure must be increased. To transfer control locally on deck, set the system pressure to 120 bar and then reduce the pump pressure in CCR to 0 bar. The system pressure must be kept 15 -20 bar higher than the required pressure for the pump”.
Ballasting/ De-Ballasting Operation
Types and Regulations
Ballast/ De-Ballast Operation
Segregated Ballast Tanks (SBT): Ballast water is taken on board to maintain stability when a vessel is emptying to pick up cargo or after unloading the cargo. Clean Ballast Tanks (CBT): A cargo tank may also be referred to as CBT in an oil tanker if it is dedicated for the carriage of ballast water (once the tank is free of the cargo). Once the ballast tanks have been inspected and checked, deballasting can be started with one or more ballast pumps.
To ballast the cargo tanks first by gravity, the sea chest valve is opened and water is directed into the ballast tanks by opening the tank valve. Later, when the gravity level decreases, the pumps can be lined up to suck up the sea chest and empty it into the ballast tanks. Ballast Water Management Plan: A copy of the BWM plan which must be carried on board and contains information on ballast water requirements such as
MASTER DRY DOCK OPERATIONS
Controlling Tank Atmosphere
Inerting Purging
Highly flammable hydrocarbon (HC) gases are normally present in the cargo tank atmosphere of oil tankers. This oxygen control is accomplished by inerting, a process of replacing the tank atmosphere with an inert gas whose O2 content is less than 8%. Thus, inertization is performed to replace the tank atmosphere by introducing inert gas to ensure that the oxygen content is 5% or less by volume.
Inerting
In this method, inert gas is pushed into the tanks at high speed so that the IG reaches even the bottom of the tank. This method works on the principle that inert gas is slightly lighter than hydrocarbon gas. The inert gas therefore enters from the top of the tank; the heavier hydrocarbon escapes from the bottom through the pipeline.
Check the oxygen content of the inert gas and set the pressure in the tanks to 700 mm WG. When the oxygen content decreases to 8% or less, reduce the inert gas pressure to 150 mm WG and close the degassing cover. When inerting of all tanks is completed, increase the line and inert gas pressure in the tank to 700 mm WG.
Purging
Maintain the inert gas velocity according to the method used for purging (dilution or displacement). To enter the tank, ensure that tank gas readings indicate that the HC concentration is reduced to 2% or less and that the oxygen content is less than 8%. Degassing, as the name suggests, means removing all hydrocarbons (HC) and inert gases from the tank to make it suitable for "human entry", ie.
Fresh air is introduced into the tank via the inert gas main pipe itself using inert gas blowers. The safest way to degas an oil tank with an inert gas system is to use a fan and bleed the tank. An O2 meter must be used before entering and the tank must also be checked with an explosion meter.
Gas Freeing
Chief Officer to ensure that only personnel assigned to Gas Clearing operations are allowed on the main deck. The proposed duration for the degassing operation should be decided long before the operation in a preoperative meeting. All crew involved in the degassing activities must wear appropriate protective gear and clothing.
Once installed, hydro blowers can be operated continuously from water pipes and are used for gas release in addition to inert gas blowers. Initially, the tank atmosphere can be vented through the gas release port for some time. During the gas release operation, atmosphere tests should be done at several levels and in each compartment of the tank.
Cargo Hold Cleaning
Crude Oil Washing Tank Cleaning
The cargo tanks are crude oil that is washed during the discharge operation using one of the deep well pumps. Ensure that at least 7-8 meters from the load head is present in the right tilt tank. As the line pressure increases, open the COW machine valves.
When the COW cycle is complete, the discharge valve of the inclined starboard pump must first be closed and the 2W cargo tanks completely removed to shore. COW of about one-fourth of the total number of tanks should be carried out keeping in mind effective sludge control. However, COW of the same tank twice in four months for the same purpose is not required.
Tank Cleaning
After the water has been filled into the waste water tank, open the machine valves of the tank cleaning line and the branch valves for all tanks to empty any remaining cargo in the tank. Align the bilge pump on the starboard side so that the seawater is directed into the main tank cleaning line. As the pressure builds, slowly open the bleed valve to pressurize the main pipe purge tank.
Align the tank cleaning pump to take suction from a fresh water tank or a designated water tank. Open the space on the tank cleaning main line to add the main line to the cleaning pump. Start the tank cleaning pump and pressurize the outlet sides to 7 or 8 bar, then open the discharge valve of the pump.
Testing
Pressure Testing of Cargo & Ballast Line
Foam Fire Fighting System Testing
Testing Cargo & Ballast Line
The compression of the lever will be used to increase the pressure in the line. Slowly increase the pressure of the system to the test levels and hold it there for some time. The strength of the hold/tank boundaries is tested by the ship's personnel under the supervision of the master.
This is done to ensure full loading of the internal bulkheads of the cargo tank. The ship's crew must create the required pressure testing conditions in accordance with the tank testing procedure specified in the vessel's SMS message. The master must also check the pressure head intended to fill the tank with regard to the state of stability.
Tank Structure Testing
The test is carried out either by using the cargo itself or by the ballast water. To test the relevant limit strength of the tank, the ship can be loaded in a checkerboard pattern such as. After successfully testing the strength of the cargo tank, the results must be entered with the date, time and.
After the ballast water has been filled, the boundaries and associated welds between the tank being tested and the adjacent cargo oil tanks should be thoroughly inspected to ensure that there is no indication of water leakage. The tank test results are recorded in designated paperwork and also in the ship's logbook. The internal and external condition of the tank boundaries and associated structure is found satisfactory by the surveyor at the time of the overall and close survey.
Fixed Foam Fire Fighting System Test
Testing the solid foam extinguishing system is done by testing the components one by one. The details of the pressure test are listed in the ship's SMS manuals for any special testing requirements. If leakage is detected from the foam monitor valve, check that it is properly closed.
Close the foam isolation valve one at a time and check that the water from the foam monitor stops completely. The foam pump operates by recirculation and the performance of the pump is measured for its rated capacity. The fire pump is an important part of the foam system and is tested during fire drills by checking the rated pressure of the pump.
Brake Testing of Mooring Winches
A brake holding capacity test is performed to determine if the winch brakes are working. The fastening part (ball carrier) is attached to the body of the winch at the hole with the help of nut screws. The hydraulic jack applies force to the clamp, which in turn torques the winch cover plate and tries to rotate it against the operation of the winch brakes.
The holding capacity of the winch brake is determined by the hydraulic pressure. There have been many incidents in the past where the symmetry between the rigging, hoist and deck cladding was not required and due to the tremendous force applied by the hoist, the rigging came loose from the cover plate and flew off, causing severe head and facial injuries to crew members ". When the pressure drops to zero, loosen the clamp nut bolts, remove the clamp and open the winch brakes to the normal position.
Emergency Inerting
Similar size flanges are provided on the inert gas main line to connect flexible hoses to the inert gas line. Another arrangement consists of a spool piece between main inert gas line and ballast line which can be rotated to connect both lines. Close all inert gas branch valves and open the flanged end cap provided in the main gas line.
Start the inert gas system and select delivery to the deck and open the deck's main shut-off valve. Twist the coil piece between the ballast lines and join it to the inert gas main line. Set up the ballast line to supply inert gas to the required tanks by opening valves on the line along with the tank valves.
