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 "Permit to work"
What is a permit to work (PTW) system on ships?
A permit to work is a formal written authorisation that controls hazardous, non-routine jobs by confirming the hazards are assessed and the right precautions are in place.
Shipboard OperationsWhat is a toolbox talk and when is it done?
What a toolbox talk is, when it happens before shipboard work, and how it turns the risk assessment and permit into a shared plan.
Shipboard OperationsWhat safety precautions are taken for working aloft on a ship?
Working aloft — up the mast, funnel or high structures — demands a permit, a safety harness, secured tools, and control of hazards such as radar, whistle and overside work.
Shipboard OperationsWhat is lock-out tag-out (LOTO) and why is it used aboard ship?
Lock-out tag-out is the practice of isolating a machine's energy sources and physically locking and tagging them off before maintenance, so it cannot be started or energised while someone is working on it.
Shipboard OperationsWhat is a hot work permit and when is it needed?
A hot work permit controls any work involving heat, flame or sparks outside a designated safe area, confirming the space is gas-free and fire precautions are in place.
Marine MachineryHow does a marine incinerator work and what can it burn?
A marine incinerator burns the ship's waste oils, sludge and solid garbage in a combustion chamber, subject to MARPOL rules on what may be incinerated and where.
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 the correct enclosed space rescue procedure?
Enclosed space rescue must never be attempted by rushing in — it demands raising the alarm and using a trained team with breathing apparatus and retrieval equipment.
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.
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.
Merchant Navy CareersWhat medical and eyesight standards are required to join the merchant navy?
Seafarers must pass a seafarer medical examination covering general fitness, eyesight and colour vision, and hearing — the standards protect safety at sea.
Shipboard OperationsWhat must be checked before enclosed space entry?
The core precautions before entering an enclosed space — atmosphere testing, permit, ventilation, standby and communications — because these spaces still kill seafarers.
Shipboard OperationsWhat are the key steps in a safe bunkering operation?
The essentials of safe bunkering — the agreed plan and checklist, scuppers and SOPEP readiness, communication, monitoring and verifying the figures.
Shipboard OperationsWhat is a risk assessment on a ship and how is it done?
A shipboard risk assessment systematically identifies the hazards of a task, evaluates the risk and puts controls in place before the work begins.
Shipboard OperationsHow is cargo secured and lashed on a ship?
Cargo is secured against the forces of the ship's motion using lashings, twistlocks and dunnage, in accordance with the ship's approved Cargo Securing Manual.
Shipboard OperationsHow 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 a Safety Management System (SMS) on a ship?
A Safety Management System is the documented set of policies and procedures, required by the ISM Code, by which a company manages the safe operation of its ships and prevention of pollution.
