Ship Science and Engineering

Marine Engineering glossary

The ship’s machinery: low-speed two-stroke and medium-speed four-stroke diesel engines from MAN, WinGD, and Wartsila, the two- and four-stroke cycles, turbocharging, scavenging, combustion and injection, and condition monitoring. Covers propulsion trains, shafting, rudders and energy-saving devices, auxiliaries (boilers, pumps, purifiers, steering gear, deck machinery), marine electrical and hybrid systems, and the fuel slate from HFO to ammonia under the IGF Code.

262 defined terms.

Showing 250 on this page (page 1 of 2).

A

Acceptance test: Factory or shop trial to verify contractual performance.
Acoustic emission monitoring: NDT/condition-monitoring technique for crack and bearing faults.
Active magnetic bearing: Bearing using controlled electromagnets, used in some turbomachinery.
Aframax (engine duty): Typical engine power class for Aframax tankers.
Aft peak tank: Aftermost ballast tank around the sterntube.
Air cooler (charge air): Heat exchanger between turbocharger and engine intake.
Air receiver: Pressurized vessel storing starting air at typically 30 bar.
Alfa Laval PureBallast: UV-based ballast water treatment system.
Ammonia (fuel): Carbon-free alternative fuel addressed by IGF/IGC future amendments.
Anti-rolling tank: Passive or active U-tube for roll damping (Frahm tank).
Auxiliary blower: Electrically driven blower for two-stroke engine starting and low load.
Auxiliary boiler: Oil-fired boiler for steam at sea when waste-heat is insufficient.
Auxiliary engine: Medium-speed engine driving a generator.
Axial pump: High-flow, low-head pump used for ballast and cooling duties.

B

Ballast water treatment system (BWTS): System complying with BWM Convention D-2 standard.
Battery hybrid propulsion: Diesel-electric plant supplemented by lithium-ion energy storage.
Bearing whitemetal: Tin-based babbitt lining of journal bearings.
Belzona repair compound: Cold polymer repair material used in marine engineering.
Bilge separator (15 ppm): Oily water separator per MEPC.107(49).
Black-start capability: Ability to restart the plant without external power.
Blue-green algae fouling: Biofouling concern in seawater cooling systems.
Boil-off gas (BOG): Vapor from LNG cargo or fuel tanks managed by reliquefaction or use.
Boiler safety valve: PSV per ASME Section I or class rules.
Bow tunnel thruster: Electric or hydraulic-driven transverse thruster.
Brake mean effective pressure (BMEP): Mean effective pressure based on brake power.
Brake-specific fuel consumption (BSFC): g/kWh fuel consumption metric.
Bunker Delivery Note (BDN): Required under MARPOL Annex VI Regulation 18.
Bypass turbocharging: System with adjustable exhaust bypass for part-load efficiency.

C

Caterpillar 3500 series: Medium-speed marine diesel family.
Centrifugal purifier: Self-cleaning separator for fuel and lube oil (Alfa Laval, GEA).
Charge air cooler: Synonym for air cooler downstream of the turbocharger.
Charge air receiver: Plenum delivering scavenge air to cylinders.
CIMAC: International Council on Combustion Engines, sets standards and round-table papers.
Closed bus tie: Switchboard operation with main busbar continuously closed.
Combined gas and steam (COGAS): Combined-cycle marine plant.
Common rail injection: High-pressure shared rail for electronically controlled injection.
Compression ignition: Diesel ignition mode without spark plug.
Compressor surge: Unstable operation of turbocharger compressor.
Condition monitoring: Vibration, oil-analysis, and performance trending of machinery.
Connecting rod: Rod between piston and crankshaft.
Controllable-pitch propeller (CPP): Propeller with hydraulic blade-pitch control.
Coolant expansion tank: Tank accommodating thermal expansion of jacket water.
Corrosion fatigue: Combined cyclic load and corrosion damage in shafting.
Crankcase explosion relief valve: Spring-loaded valve per IACS UR M9.
Crankshaft deflection: Web-deflection measurement indicating alignment.
Cross-head: Sliding crosshead between piston rod and connecting rod in 2-stroke engines.
Cylinder liner: Replaceable cast-iron liner forming combustion chamber wall.
Cylinder lubrication (BN): Alkaline cylinder lube oil neutralizing acidic combustion.

D

Daihatsu DK-20: Medium-speed marine engine family.
Deck crane (hydraulic): Hydraulically driven cargo crane.
Deck machinery: Anchor windlass, mooring winches, and cranes.
Diesel index: Empirical fuel ignition quality index.
Diesel-electric propulsion: Multiple gensets feeding propulsion motors via main bus.
Direct-coupled propulsion: Two-stroke engine directly coupled to propeller without gearbox.
Dispersant additive: Lube oil additive keeping soot in suspension.
DNV SILENT class: Underwater radiated noise notation.
Double-bottom: Structural arrangement providing tanks below cargo holds.
Dual-fuel engine: Engine running on both liquid and gaseous fuels (e.g., WinGD X-DF).
Duplex stainless steel: Used in seawater pumps and scrubber piping.

E

Economizer (exhaust gas boiler): Waste-heat steam generator on exhaust uptake.
EGR (Exhaust Gas Recirculation): NOx control method per MARPOL Annex VI Tier III.
Electric motor (squirrel cage): Common asynchronous AC motor type.
Electrical Load analysis (ELA): Calculation of generator capacity per operational mode.
Emergency diesel generator: Independent set serving emergency switchboard per SOLAS.
Emergency fire pump: Independent fire pump per SOLAS Reg. II-2/10.
Emergency stop circuit: Hardwired shutdown loop for machinery.
Energy Efficiency Existing Ship Index (EEXI): Required technical index for existing ships.
Engine Power Limitation (EPL): Limiter device per MEPC.335(76).
Engine room console: Local control station in engine control room.
Engine Room Resource Management (ERM): STCW-mandated competency in engine watch.
Enviroil clarifier: Oily-water separator unit.
EPL Onboard Management Manual (OMM): Documentation of EPL settings.
Exhaust manifold: Common pipework collecting exhaust from cylinders.
Exhaust valve cage: Removable cylinder-head housing for exhaust valve.
Expansion tank: Header tank for cooling system.

F

Fast-acting shutoff valve: Tank shutoff valve required by IGF/IGC.
Filter, indicator type (lube oil): Duplex filter with differential pressure indicator.
Final drive (azimuth thruster): Right-angle gear of an azimuth propulsion unit.
Fire detection system (FDS): SOLAS-compliant smoke/heat detection network.
Flettner rotor: Wind-assisted propulsion using Magnus effect.
FlexView (MAN ES): Engine monitoring and trending system.
Forced lubrication: Pressurized lube oil supply by gear-driven pump.
Four-stroke engine: Otto/Diesel cycle engine with separate intake, compression, power, exhaust strokes.
FRAM filter: Brand of lube filter element historically used onboard.
Frequency converter (VFD): Variable-frequency drive for AC motors.
Fresh-water generator (evaporator): Vacuum distillation FWG, e.g., Alfa Laval AQUA.
Fuel injection pump: Plunger pump delivering high-pressure fuel to injector.
Fuel oil booster module: Skid raising HFO pressure and temperature to injection conditions.
Fuel oil viscometer: Inline viscosity control for HFO heaters.

G

Gas combustion unit (GCU): Thermal oxidizer for excess BOG on LNG carriers.
Gasoil: Marine gasoil (MGO) per ISO 8217 DMA.
GEA Westfalia separator: Disc-stack centrifuge for fuel/lube oil.
Generator excitation: AVR-controlled field current of synchronous generator.
Generator parallel operation: Synchronizing two generators on the main bus.
GHG Intensity (FuelEU): gCO2eq/MJ metric per FuelEU Maritime.
GreenSteam DBM: Performance monitoring system.
Gross calorific value (GCV): Higher heating value of fuel.

H

Hamworthy Moss reliquefaction: Reliquefaction plant for LNG carriers.
Hatch cover (Macgregor): Hydraulically operated weathertight hatch.
Heat balance: Energy accounting in propulsion and waste-heat systems.
Heavy fuel oil (HFO): Residual marine fuel, RMG 380, ISO 8217.
HFO settling tank: Tank where heated HFO settles before purification.
High-temperature jacket water: Cooling circuit at ~85-90 °C around cylinder jackets.
Himsen H21/32: Hyundai Heavy Industries medium-speed engine family.
Hot-corrosion (turbine): Vanadium-sodium attack on hot-section blades.
Hydraulic power pack (HPU): Power unit for steering, hatch covers, deck machinery.
Hydrogen fuel: Cryogenic or compressed H2, addressed in upcoming IGF amendments.
Hyundai HiMSEN: Brand of HHI medium-speed engines.

I

Idle running: Engine running at no-load minimum speed.
IGC Code: International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk.
IGF Code: International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels.
IMO NOx Tier III: NOx emission limit for ECA-built engines since 2016/2021.
Incinerator (marine): Onboard waste incinerator per MEPC.244(66).
Indicator diagram (PV): Cylinder pressure-volume diagram for performance.
Indicator power: Power computed from indicator diagram before friction losses.
Indirect cooling system: Closed fresh-water loop cooled by central seawater coolers.
Inert Gas System (IGS): Required on tankers under SOLAS II-2/16.
Injection timing: Crank-angle reference for start of injection.
Inlet guide vanes (turbo): Variable IGV controlling compressor mass flow.
Inverter (drive): DC-AC converter in propulsion drives.
IsatMarine performance suite: Performance and emissions monitoring.

J

Jacket cooling water: HT cooling loop around cylinder block.
Jet pump (eductor): Stripping eductor used in cargo and bilge service.
JIS marine flanges: Japanese piping flange standard widely used on ships.
Journal bearing: Plain sliding bearing supporting rotating shaft.

K

Keel cooler: External heat exchanger on the hull for closed-loop cooling.
Knock (engine): Abnormal combustion in gas/dual-fuel engines.
Kongsberg K-Chief: Integrated automation system for marine engineering plant.
KORT nozzle: Accelerating ducted-propeller nozzle.

L

LFL (low flash fuel): Fuels with flash point < 60 °C addressed by IGF Code.
LNG bunkering manifold: ISO-standard transfer connection for LNG.
Load profile: Distribution of engine load with time used for design.
Local control panel (LCP): Engine-mounted control and indication panel.
Low-pressure dual fuel (LPDF): Otto-cycle gas engine like Wartsila 31DF.
Lubricator (cylinder): Electronic lubricator dosing cylinder oil to liners.

M

Main engine torsiograph: Instrument measuring shafting torsional vibration.
Maintenance management system (PMS): Class-approved planned maintenance software.
MaK M32C: Caterpillar medium-speed marine engine.
MAN 32/44CR: Four-stroke common-rail diesel engine.
MAN B&W G70ME-C9.5: Long-stroke 70 cm bore Tier-II two-stroke engine.
MAN B&W S60ME-C: Two-stroke 60 cm bore electronically controlled engine.
MAN ES ME-GA: Two-stroke ammonia dual-fuel engine (announced).
MAN ES ME-GI: Two-stroke high-pressure gas injection dual-fuel engine.
MAN ES ME-LGIM: Two-stroke methanol dual-fuel engine.
MAN L51/60DF: Four-stroke dual-fuel medium-speed engine.
MAN PrimeServ: After-sales service organization.
Marine gas oil (MGO): DMA distillate fuel per ISO 8217.
Marine growth prevention system (MGPS): Anti-fouling system for seawater intakes.
MARPOL Annex VI: Air pollution and energy-efficiency annex.
Master fuel pump: Pump supplying main fuel rail.
MEPC (IMO): Marine Environment Protection Committee.
Mitsubishi MET turbocharger: MHI marine turbocharger family.
Mitsubishi UEC: Two-stroke engine family licensed from Mitsubishi.
Mooring winch (split drum): Drum-type winch for berthing and harbor operations.
Motor controlcenter (MCC): Switchboard for auxiliary motors.
MTU 4000 series: High-speed four-stroke engines.

N

Niigata Z-Peller: Azimuthing propulsion unit.
Nitrogen generator (PSA): Pressure-swing adsorption nitrogen plant.
Nominal continuous rating (NCR): Sea service power, typically 0.85 MCR.
NOx Technical Code: Issued under MARPOL Annex VI.

O

Oil mist detector (OMD): Crankcase oil-mist detection per UR M10.
Oily water separator (OWS): 15 ppm separator per MEPC.107(49).
Optimarin BWTS: UV-based ballast treatment system.
Otto cycle (gas engine): Premixed spark/pilot-ignited cycle used in dual-fuel engines.
Overspeed trip: Mechanical/electrical trip on engine overspeed.

P

Pacific Brake: Brake/clutch unit on shaft generator drives.
PAO synthetic oil: Polyalphaolefin base lube oil.
Parallel operation switchboard: Switchboard with synchronization equipment.
Permanent magnet motor: PM propulsion motor used in azimuth thrusters.
PG governor: Woodward hydraulic-mechanical engine governor.
Piston cooling jet: Oil jet cooling underside of piston crown.
Pneumatic control loop: Air-signal control loop on legacy plant.
Polar Class engines: Engines with reinforced specification for ice operations.
Power management system (PMS): Generator load sharing and start/stop logic.
Power take-in (PTI): Shaft motor drawing power from main bus to assist propulsion.
Power take-off (PTO): Shaft generator extracting electrical power from main engine.
Pre-mixed combustion: Otto-cycle combustion of premixed gas/air.
Pre-swirl stator: Energy-saving device with vanes ahead of propeller.
PureSOx (Alfa Laval): Open/closed-loop exhaust gas scrubber.

Q

Quench oil cooler: Cooler for hydraulic oils in steering gear.
Quill shaft: Hollow torsion shaft used in flexible couplings.

R

Radiator (engine): Air-blast cooler used on some small craft.
RaPL (ramp-up power limitation): Software-based EPL implementation.
Reduction gearbox: Single or twin-input reduction unit between engine and shaft.
Refrigeration plant: HFC/HFO/CO2 refrigeration for provisions, reefer.
Reliquefaction plant: BOG handling unit on LNG carriers.
Renk gearbox: Marine reduction gear maker.
Residual fuel: Heavy residual marine fuel grades RMG/RMK.
Resilient mount: Vibration-isolating engine mount.
Ringing (propulsion shaft): Torsional resonance in shafting.
Rolls-Royce Kamewa waterjet: Waterjet propulsion family.
Rolls-Royce Mermaid: Podded propulsor (legacy).
Rotor cap (turbo): Component of turbocharger rotor assembly.
Run-down speed (genset): Minimum stable speed for parallel operation.

S

Sacrificial anode: Zinc/aluminum anode for hull and tank protection.
Sankey diagram (engine): Energy balance visualization for an engine.
Schottel SRP: Azimuth thruster series.
Scrubber tower: Exhaust gas cleaning tower.
Sea chest: Hull recess for seawater intake.
Selective Catalytic Reduction (SCR): NOx aftertreatment using urea/ammonia.
Self-priming pump: Pump capable of evacuating air from its suction line.
Shaft alignment (cold/hot): Optical/laser alignment of propulsion shafting.
Shaft brake (hydraulic): Brake holding shaft for maintenance or PTO mode.
Shaft earthing slip ring: Brush ring grounding shaft to hull.
Shaft generator: Generator driven by main engine via PTO.
Shock load: Transient impact load on machinery, e.g., from grounding.
Shore connection (HVSC): High-voltage shore connection per IEC/IEEE 80005-1.
Single-fuel mode: Operation of dual-fuel engine on liquid only.
Sliding-pressure operation: Boiler operation with variable pressure.
Sludge tank: Tank for engine and separator sludges.
Smart Press Ship Engine (Wartsila): Engine performance optimization.
SOLAS Reg. II-1/26: Machinery installation requirements.
Soot blower: Steam/air blower for boiler tube cleaning.
Standby generator: Backup genset typically on auto-start.
Steering gear (rotary vane): Hydraulic rotary-vane actuator for rudder.
Stern tube bearing: Aft propeller-shaft bearing, white-metal or composite.
Stuffing box: Sealing arrangement around shaft penetration of bulkhead.
Sulzer RT-flex: Common-rail electronically controlled two-stroke engine.
Sulzer RTA series: Legacy Sulzer two-stroke engines.
Superchargers: Mechanically driven blowers, rare in modern engines.

T

Tail shaft: Aftermost section of propeller shaft.
TBN (Total Base Number): Alkalinity rating of cylinder lube oil.
TBO (time between overhauls): Overhaul interval for major engine parts.
Telegraph (engine order): Bridge-engine engine-speed indicator.
Tier II/Tier III NOx: MARPOL Annex VI NOx emission tiers.
Tonne CO2 equivalent: Common unit for FuelEU and EU ETS reporting.
Torsional vibration calculation (TVC): Class-approved shafting analysis.
Total catch (centrifuge): Sludge mass per processed feed in separator.
Trent 30 (Rolls-Royce): Marine aero-derivative gas turbine (legacy).
Tunnel thruster: Transverse thruster mounted in a tunnel.
Turbo compounding: Power-turbine recovery of exhaust energy.
Turbocharger (MET, TPL, A100-L): Mitsubishi, ABB, MAN-ES turbo series.
Two-stroke crosshead engine: Slow-speed engine with crosshead bearing.

U

UHP fuel pump: Ultra-high-pressure fuel pump for diesel injection (>1500 bar).
Uniflow scavenging: Scavenge arrangement with intake ports and exhaust valve.
Universal coupling: Flexible coupling on shafting.
Upper bearing (turbocharger): Bearing on the compressor side.

V

V-belt drive: Belt drive on auxiliary engines for water pumps and alternators.
Vapor return line: Cargo gas return between ship and shore on tankers/gas carriers.
Variable Geometry Turbocharger (VGT): Turbocharger with variable nozzle vanes.
Variable injection timing (VIT): System adjusting fuel injection timing with load.
Vibration isolator: Spring/elastomeric isolator for machinery foundations.
Voith Inline Thruster: Tunnel thruster with permanent magnet motor.
Voith Schneider: Cycloidal propeller for tugs and ferries.
Volute pump: Single-stage centrifugal pump with volute casing.

W

Wartsila 31: Medium-speed four-stroke engine family.
Wartsila 32/34DF: Medium-speed dual-fuel engine families.
Wartsila 46F: Four-stroke medium-speed engine.
Wartsila Sulzer X92: Large bore two-stroke for ULCV (transferred to WinGD).
Waste heat recovery (WHR): Steam/power recovery from main engine exhaust.

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