24 terms.
- Tailshaft Survey
A classification survey of the propeller shaft withdrawn from the stern tube to inspect for corrosion, cracking, and bearing wear.
- Tank Cleaning
The process of removing cargo residues and gas from cargo tanks using water, chemicals, or crude oil washing prior to loading a new cargo.
- Technical Superintendent
A shore-side engineer responsible for overseeing planned maintenance, drydockings, and technical compliance of assigned vessels.
- Territorial Waters
The belt of coastal waters extending up to 12 nautical miles from the baseline over which a coastal state has full sovereignty.
- Third Engineer
A junior engineer officer responsible for a watchkeeping duties and maintenance of assigned machinery and systems.
- Third Mate
The most junior certificated deck officer, typically responsible for maintaining fire-fighting and life-saving appliances.
- Three-Point Bearing
A position fix obtained by simultaneously measuring horizontal angles between three charted objects using a sextant or compass.
- Tokyo Memorandum of Understanding
A regional port state control arrangement covering the Asia-Pacific region, established in 1993 with 21 member authorities.
- Tonnage Certificate
A statutory certificate stating a ship's gross and net tonnage calculated under the International Tonnage Convention 1969.
- Tonnes Per Centimetre
The mass required to change a vessel's mean draft by one centimetre, used to calculate draft changes during loading or discharging.
- Traffic Separation Scheme
An IMO-adopted routing measure separating opposing traffic into lanes to reduce collision risk in congested waters.
- Transit
Two or more objects in line with each other, used as a position line or to verify vessel alignment in a channel.
- Trim
The difference between forward and aft draft; a vessel trims by the head if forward draft exceeds aft draft.
- Trim by the Head
A trim condition where the forward draft exceeds the aft draft, reducing steering effectiveness and increasing wave-making resistance.
- Trim by the Stern
A trim condition where the aft draft exceeds the forward draft, generally preferred for sea passage to improve propulsive efficiency.
- True Bearing
A bearing measured clockwise from true north, used for chart plotting and unaffected by magnetic variation or compass deviation.
- Turbocharger
A device driven by exhaust gas that compresses intake air to increase diesel engine power output and fuel efficiency.
- Turbocharger Surge
An abnormal flow reversal in a turbocharger compressor, evidenced by a loud banging or barking noise, caused by sudden load changes.
- Turnbuckle
A threaded tensioning device fitted in a lashing rod or wire to adjust and tighten cargo securing arrangements.
- Turning Gear
An electric motor-driven gear unit that slowly rotates the main engine crankshaft for maintenance, cooling-down, or warming-through.
- Twenty-foot Equivalent Unit
Standard unit of cargo capacity equivalent to one 20-foot ISO shipping container, used to measure container ship capacity.
- Twistlock
A securing device that fits into container corner castings and locks by a 90° twist to stack and secure containers.
- Two-Stroke Engine
A type of internal combustion engine completing the power cycle in a single up-and-down piston stroke, common in large slow-speed marine main engines.
- Typhoon
A tropical cyclone of the western North Pacific with sustained winds exceeding 64 knots, the regional name for a hurricane.