Tanker operations glossary Flashcards
Approved Equipment
Equipment of a design that has been tested and approved by an appropriate authority such as a government department or classification society. The authority should have certified the equipment as safe for use in a specified hazardous atmosphere.
Auto Ignition
The ignition of a combustible material, without initiation by a spark or flame, when the material has been raised to a temperature at which self-sustaining combustion occurs.
Ballast
Seawater introduced into cargo or clean ballast tanks for the return leg of a voyage to the next loading port. It is the additional weight necessary to bring the vessel to a suitable draft and trim and to reduce stresses and improve stability.
Barrel
Standard unit of volume commonly used in trading oil and on US ships, equivalent to 42 gallons.
Block valve
There are different types of block valves which, when closed, may stop the oil from flowing in either direction. Types include remote gate valves and manual gate valves.
Bonding
The connecting together of metal parts to ensure electrical continuity.
Butterworth
A brand name of tank cleaning equipment, commonly applied to all portable tank cleaning equipment. Butterworth plates are plates flush with the deck that are opened to admit portable tank cleaning machines into the top of a tank.
Cavitation
A condition in the operation of a pump that occurs when the pressure in the suction line falls below the vapour pressure of the cargo.
CCR
Cargo Control Room
Check valves
These valves are designed to operate one-way and stop oil from reversing flow. Flowing oil holds this type of valve open, and they close by themselves when oil isn’t flowing or changes flow direction.
Chicksan (boom)
A mechanical steel arm or boom to connect the shore pipes with the ship’s manifold, while allowing large movement up and down and some movement sideways.
Cofferdam
A void space used to physically separate the cargo area from non-cargo areas.
Combustible (also referred to as ‘Flammable’)
Capable of being ignited and of burning.
Combustible gas indicator
An instrument for measuring the composition of hydrocarbon gas/air mixtures, usually giving the result as a percentage of the lower flammable limit.
COW
Crude Oil Washing. This uses recycled crude oil cargo to wash down tanks that are in the process of emptying or have just been emptied.
Discharge pressure
The oil pressure as it leaves a pump
Earthing (also referred to as ‘Grounding’)
The electrical connecting of equipment to the main body of the earth to ensure that it is at earth potential. On board ship the connection is made to the main metallic structure of the ship which is at earth potential because of the conductivity of the sea.
Fire wire
Emergency towing wire affixed to the ship at bow and stern on the offshore side while in port. The eye is lightly fastened just above the waterline. This fastening is broken by a towing-off vessel, allowing the wire to run out to a suitable length.
Flammable range (also referred to as ‘Explosive range’)
The range of hydrocarbon gas concentrations in air between the lower and upper flammable (explosive) limits. Mixtures within this range are capable of being ignited and of burning.
Flash point
The lowest temperature at which a liquid gives off sufficient gas to form a flammable gas mixture near the surface of the liquid. It is measured in the laboratory in standard apparatus using a prescribed procedure.
Gas free
A tank, compartment or container is gas free when sufficient fresh air has been introduced into it to lower the levels of any flammable, toxic or inert gases to those required for a specified purpose, e.g. hot work, entry etc.
Gas free certificate
A certificate issued by an authorized person confirming that at the time of testing a tank, compartment or container it was gas free for a specific purpose.
Gauze Screen (also referred to a ‘Flame screen’)
A portable or fitted device incorporating one or more corrosion resistant wire woven fabrics of very small mesh used for preventing sparks from entering a tank or vent opening or, for a short time, preventing the passage of flame.
Hot work
Work involving sources of ignition or temperatures sufficiently high to cause the ignition of a flammable gas mixture. This includes any work requiring the use of welding, burning or soldering equipment, blow torches, some power driven tools, portable electrical equipment which is not intrinsically safe or contained within an approved explosion proof housing, sand blasting, or internal combustion engines.
