Maritime Knowledge Base
Browse questions and answers across marine machinery, merchant navy careers, shipboard operations and maritime glossary terms.
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Marine Machinery
Troubleshooting guides for pumps, boilers, purifiers, compressors and auxiliary systems.
Merchant Navy Careers
Questions about joining the merchant navy, exams, cadetships, ranks and sea-time.
Maritime Glossary
Plain-English definitions of shipping, engine-room, navigation and regulatory terms.
Shipboard Operations
Practical Q&A for watchkeeping, safety, maintenance routines and onboard documentation.
Results for "Tank cleaning"
How is a cargo tank cleaned on a tanker?
Cargo tanks are cleaned with fixed or portable washing machines using water or crude oil, followed by draining, gas-freeing and ventilation, before a change of cargo, entry or repair.
Shipboard OperationsWhat is an inert gas system on a tanker and why is it needed?
An inert gas system fills a tanker's cargo tanks with oxygen-poor gas so the atmosphere cannot support combustion, preventing explosions in and around the cargo.
Shipboard OperationsWhat is crude oil washing (COW) on a tanker?
Crude oil washing cleans a tanker's cargo tanks during discharge by spraying them with the crude cargo itself, which dissolves clingage and reduces residue, sludge and pollution.
Marine MachineryWhat is the difference between a purifier and a clarifier?
A purifier separates both water and solids from oil, while a clarifier removes only fine solids from oil that contains little or no water — often the two run in series.
Marine MachineryWhy does the oily water separator 15 ppm bilge alarm keep activating?
The 15 ppm alarm on the oily water separator stops overboard discharge when the oil content is too high — the causes lie in the separator, the monitor or the feed.
Marine MachineryHow does a marine centrifugal oil purifier work?
A marine purifier cleans fuel and lubricating oil by spinning it at high speed so that water and solids separate out — here is the working principle.
Marine MachineryHow does a ship's sewage treatment plant work?
A marine sewage treatment plant breaks down the ship's sewage — usually biologically — and disinfects it so that the treated effluent meets MARPOL Annex IV discharge standards.
Marine MachineryWhat is a central cooling system on a ship and why is it used?
A central cooling system uses seawater to cool a closed freshwater circuit, which in turn cools the machinery — reducing seawater corrosion and fouling in the equipment.
Marine MachineryHow does a ship's fuel oil system store, treat and deliver fuel to the engine?
The fuel oil system takes bunkers from the storage tanks, settles and purifies them, heats heavy fuel to the right viscosity, and delivers clean fuel under pressure to the engine.
