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 "Ballast water"
What is ballast water and why is it managed?
What ballast water is, why ships carry it, and why it is now exchanged or treated under the Ballast Water Management Convention.
Shipboard OperationsHow is ballast water managed and treated on board a ship?
Under the Ballast Water Management Convention, ships manage ballast water either by mid-ocean exchange or, increasingly, by treating it through an approved system before discharge.
Merchant Navy CareersWhat is an electro-technical officer (ETO) and what do they do?
An electro-technical officer is a specialist engine-department officer responsible for a ship's electrical, electronic and control systems, a rank formalised under STCW.
Shipboard OperationsWhat is a draught survey and how is cargo weight calculated?
A draught survey determines the weight of bulk cargo loaded or discharged by measuring the ship's draughts and calculating the change in its displacement.
Maritime GlossaryWhat is deadweight tonnage (DWT)?
Deadweight tonnage defined — the total weight a ship can carry — and how it differs from displacement and gross tonnage.
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 OperationsWhy are enclosed spaces on ships so dangerous?
Enclosed spaces kill because their atmosphere can be oxygen-deficient, toxic or flammable with no outward sign — and rescuers who rush in become the next victims.
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 MachineryHow does a marine centrifugal pump work?
A centrifugal pump moves liquid by spinning it with an impeller, which throws the liquid outward and converts its speed into pressure — the most common type of pump aboard ship.
Shipboard OperationsWhat precautions does a ship take in heavy weather?
In heavy weather a ship reduces speed and adjusts course to ease its motion, secures everything for sea, manages ballast and stability, and guards against dangerous rolling.
