Marine Engine Model Decoder (Naming Conventions, All Major Makers)

Why engine designations are structured

Marine engine programmes evolve over decades. A maker that ships engines from 200 mm bore aux units to 980 mm bore main propulsion has hundreds of variants in production at any given time. Without a structured naming convention, customers, classification societies, surveyors and shipyards would face a combinatorial nightmare every time an engine specification changed hands. A model number like 6S60MC-C is therefore designed to be parseable: every character maps to a property of the engine, and within a maker’s lineage the same character has the same meaning across thousands of engines.

This is not a marketing convention. Class society type approvals, IMO EIAPP certificates, engine builders’ licences and classification society plan approvals all reference the engine by its structured designation. The naming convention is the engine’s identity for regulatory and contractual purposes.

The grammars below are presented in roughly the order of fleet share, starting with the two-stroke makers that dominate large main propulsion and continuing with the four-stroke aux-engine makers.

MAN B&W (2-stroke)

MAN B&W traces to the 1898 collaboration between Rudolf Diesel and Burmeister & Wain of Copenhagen, with MAN AG of Augsburg producing the first commercial diesel engine that same year. The two firms’ 2-stroke programmes merged in 1980, and today’s MAN Energy Solutions marine division licenses the design to builders worldwide (Hyundai Heavy Industries, Mitsui E&S, Doosan, Dalian Marine Diesel, Hyundai-Himsen). The current programme accounts for an estimated 70 to 80 percent of large 2-stroke engines on order.

Grammar

<cylinders><stroke><bore><type>[-<sub>][<mark>][<fuel suffix>]

For example, 6S60MC-C parses as:

Stroke prefix

Type code

Mark numbers

A trailing decimal (e.g. ME-C9.5, ME-C10.5) indicates the mark version, a sequential refinement step within a type code. Higher marks typically improve brake-specific fuel oil consumption (BSFC), extend the rated power range, or add emissions-tuning capability. The same engine name without a mark indicates the original baseline (mark 1).

Worked examples

• 6S60MC-C: 6 cyl, super-long stroke, 600 mm bore, MC compact. Legacy programme, widely operated on bulk carriers and tankers.
• 7G80ME-C10.5: 7 cyl, ultra-long Green stroke, 800 mm bore, ME-C mark 10.5. Modern flagship for VLCCs and Suezmax tankers.
• 8G95ME-GI: 8 cyl, Green stroke, 950 mm bore, high-pressure LNG dual-fuel. Ultra Large Container Ships (24,000+ TEU).
• 6G50ME-LGIM: 6 cyl, Green stroke, 500 mm bore, methanol dual-fuel. Methanol-ready newbuild container feeders.
• 12K98MC: 12 cyl, short stroke, 980 mm bore, MC. The largest commercial 2-stroke ever built (Maersk E-class predecessor era).

For broader context on the architecture see two-stroke marine diesel engine fundamentals, crosshead diesel engine architecture, uniflow scavenging, common-rail fuel injection on two-stroke engines and Tier III compliant two-stroke engines.

WinGD

Winterthur Gas & Diesel Ltd. was created in 2015 when Wärtsilä spun off its 2-stroke business; majority ownership passed to China State Shipbuilding Corporation (CSSC) in 2016. WinGD inherited the Sulzer 2-stroke lineage that Wärtsilä had acquired in 1997. The current programme is the X-series, which replaced the older RT and RT-flex families, with a dual-fuel X-DF derivative that introduced low-pressure LNG operation to the 2-stroke market.

Grammar

<cylinders>X<bore>[<fuel suffix>]

Worked examples

• 8X92DF: 8 cyl, X92 platform (920 mm bore), dual-fuel. Flagship for 23,000+ TEU LNG-fuelled container ships.
• 6X62DF-S: 6 cyl, 620 mm bore, X-DF second-generation. Mid-size container vessels.
• 7X82: 7 cyl, 820 mm bore, conventional oil-fuelled.

The X-series is gradually displacing the legacy RT-flex on newbuilds; the smaller bores (X35, X40) entered series production from approximately 2018. See WinGD corporate history and the in-depth WinGD X-DF dual-fuel architecture article.

Wärtsilä 2-stroke (Sulzer / RT)

Sulzer Diesel of Winterthur, Switzerland, was one of the three twentieth-century 2-stroke houses (alongside MAN B&W and Mitsubishi). Wärtsilä acquired Sulzer in 1997 and continued the RT, RTA and RT-flex programmes until the 2015 spin-off to WinGD. The designation lineage is sometimes called “Sulzer RT” interchangeably with “Wärtsilä RT”.

Grammar

Worked examples

• RTA84T-D: RTA series, 840 mm bore, T-variant (tanker tuning), D revision. 1990s-era tanker propulsion.
• RT-flex96C-B: RT-flex, 960 mm bore, C-variant (container tuning), B revision. The famous “world’s largest” reciprocating engine on the Emma Maersk class.
• RTA62U: RTA, 620 mm bore, universal variant.

These engines remain widespread on the existing fleet but are not built as new; WinGD’s X-series has succeeded them. See Sulzer marine diesel engines history and Wärtsilä corporate history.

Mitsubishi UEC

Mitsubishi Heavy Industries Marine Machinery & Equipment Co. (MHI-MME) developed the UEC (“Universal Engine, Crosshead”) family independently of the European 2-stroke houses. UEC engines have been in continuous production since the 1950s and compete in the same market segments as MAN B&W’s S and G families.

Grammar

[<cylinders>]UEC<bore><generation>

Generation codes

Worked examples

• 6UEC60LSII: 6 cyl, UEC60 platform (600 mm bore), LSII generation.
• UEC50LSE: UEC50 (500 mm bore), eco variant, no cylinder count given (used as a programme-level designation).
• 7UEC85LSC: 7 cyl, UEC85 (850 mm bore), compact-frame variant.

See Mitsubishi UE engine family overview and Mitsubishi UEC two-stroke engines for deeper history.

MAN 4-stroke

The MAN 4-stroke programme spans medium-speed engines from 210 mm to 580 mm bore. These are used as auxiliary generators, geared main propulsion (small to medium vessels), and ferries / cruise ships where electric propulsion separates the engine from the propeller. The naming convention is bore/stroke in millimetres rather than centimetres, with optional fuel-system and emissions-tier suffixes.

Grammar

<cylinders><config><bore>/<stroke>[<suffix>]

Configurations

Suffixes

Worked examples

• 9L48/60CR: 9 cyl, in-line, 480/600 mm bore/stroke, common-rail.
• 12V32/44CR: 12 cyl, V-bank, 320/440 mm.
• 9L21/31: 9 cyl, in-line, 210/310 mm. Small aux genset.
• 8L51/60DF: 8 cyl, 510/600 mm, dual-fuel.

For the broader 4-stroke architecture see medium-speed four-stroke marine engines and trunk-piston engine architecture.

Wärtsilä 4-stroke

Wärtsilä’s 4-stroke programme inherits the Vasa, Wichmann and Stork lineages and ranges from 200 mm to 640 mm bore. The engines are used for medium-speed main propulsion (cruise ships, ferries, RoRo, OSV), aux gensets, and dual-fuel LNG carrier propulsion.

Grammar

<cylinders><config>W<bore>[<suffix>]

The W prefix is sometimes elided (Wärtsilä 32, W32, 9L32 are all the same engine). When the cylinder count and configuration are written, they precede the bore.

Suffixes

Worked examples

• 9L46F: 9 cyl, in-line, W46 platform (460 mm bore), standard fuel.
• 12V34DF: 12 cyl, V-bank, W34 platform, dual-fuel.
• 16V32: 16 cyl, V-bank, W32 platform.

The Wärtsilä W-series has dedicated wiki articles per platform: W20, W31, W32, W46F, and the W50DF dual-fuel engine.

Hyundai HiMSEN

HiMSEN (“Hyundai Marine and Stationary Engine”) is HHI’s indigenously developed 4-stroke programme, in production since 2000. The designation mirrors the MAN 4-stroke pattern: H<bore>/<stroke> in millimetres, optionally prefixed with cylinder count.

Grammar

[<cylinders>]H<bore>/<stroke>[<suffix>]

Worked examples

• 6H21/32: 6 cyl, 210/320 mm.
• 9H32/40: 9 cyl, 320/400 mm.
• H46DF: 460 mm bore, dual-fuel. (Stroke is implied; the H46 platform has stroke 580 mm.)

MaK / Caterpillar

MaK (“Maschinenbau Kiel”) was a German medium-speed engine maker that Caterpillar acquired in 1997. The programme became part of Cat Marine and is now sold under the Caterpillar brand using the legacy MaK designation.

Grammar

[<cylinders>]M<bore>[<suffix>]

Suffixes

Worked examples

• 6M32C: 6 cyl, M32 platform (320 mm bore), tier-compliant.
• 9M43C: 9 cyl, M43 (430 mm), tier-compliant.
• 8M46DF: 8 cyl, M46 (460 mm), dual-fuel.

For the MaK programme history see MaK Maschinenbau Kiel marine engines and Caterpillar Marine corporate history. Caterpillar’s own large-bore 3500 and 3600 series (e.g. 3508, 3612) use a different grammar; see the dedicated Caterpillar 3500 marine engine article and the Caterpillar 3500/3600 section below.

Daihatsu Diesel

Japanese maker of medium- and high-speed marine 4-strokes, primarily for auxiliary use. Designation prefixes:

Worked examples

• 6DK-20: 6 cyl, DK20 platform (200 mm bore).
• 6DK-28: 6 cyl, DK28 (280 mm).
• 8DK-32: 8 cyl, DK32 (320 mm).

See Daihatsu InfiNeart marine engines for the modern programme.

Niigata Power Systems

Niigata, part of the IHI Corporation group, produces medium-speed 4-strokes for auxiliary, tug and fishing-vessel use. The HX/AHX/HLX nomenclature reflects successive generations:

Worked examples

• 6L28AHX: 6 cyl, in-line, 280 mm bore, advanced HX.
• 6L33HLX: 6 cyl, 330 mm bore, long-stroke HX.
• MG28HLX: marine-genset designation, 280 mm bore.

See Niigata Power Systems marine engines.

Yanmar

Yanmar’s marine-commercial medium-speed range uses two parallel naming conventions:

Worked examples

• 6EY26: 6 cyl, EY26 platform (260 mm bore).
• 6EY22: 6 cyl, 220 mm.
• 6N330: 6 cyl, N-series 330 (330 mm bore: note that the N-series gives bore in millimetres, unlike EY which gives bore in centimetres).

See Yanmar marine engines for the corporate and product history; for high-speed pleasure-craft Yanmar variants see the Yanmar high-speed section below.

Bergen / Rolls-Royce

Bergen Engines AS of Norway makes medium-speed 4-strokes used widely in offshore vessels, gas-fuelled ferries and naval auxiliaries. Owned by Rolls-Royce Marine until 2021, then sold to Langley Holdings. The Bergen designation uses bore:stroke notation in centimetres separated by a colon, an unusual convention that distinguishes it at a glance.

Grammar

<series>:<stroke><config><cylinders>

Series prefix:

Configuration:

Worked examples

• B33:45L9: B-series, 330/450 mm bore/stroke, in-line, 9 cyl.
• B35:40V12: B-series, 350/400 mm, V-bank, 12 cyl.
• C25:33L9: C-series (compression-ignition), 250/330 mm, in-line, 9 cyl.

See the dedicated Bergen B33:45 medium-speed engine article for the most-deployed model in the family.

Pielstick / SEMT-Pielstick

SEMT (Société d’Études de Machines Thermiques) developed the Pielstick PA, PB, PC medium-speed 4-strokes from the 1950s onwards in France, in close partnership with MAN. The brand became part of MAN Energy Solutions in 2006. Pielstick engines are the dominant medium-speed plant on French and Italian frigates, ferries, and offshore support vessels of 1980s-2000s vintage. See the SEMT-Pielstick engines article and SEMT-Pielstick medium-speed engines deep dive.

Grammar

[<cylinders>]P<series><bore>[B][-<mark>][<config>]

Series letters: PA (older direct-fuel-injection), PB (improved PA with higher MEP), PC (designed-from-scratch successor in three sub-families: PC2, PC2-2, PC2-5, PC2-6, PC4).

Worked examples

• PC2-6: PC series, generation 2.6. Bore 400 mm, stroke 460 mm. The most-built medium-speed engine in French naval and merchant service.
• 12PC2-6V: 12 cyl V-bank PC2-6.
• PA6B: PA series, 280 mm bore, B revision. Common on French Type 23 frigates and OSVs.
• 16PC2-5V: 16 cyl V-bank PC2-5.
• PC4: PC series 4, 570 mm bore, 660 mm stroke. Largest Pielstick.

Cummins Marine

Cummins has built marine engines since the 1930s, with current programmes spanning the B-series (industrial duty), C/L-series (workboat duty), N-series (legacy heavy duty), and the modern QSB / QSC / QSL / QSM / QSK common-rail families. Major presence on tugs, OSVs, fishing vessels, river towboats and small-craft commercial. See Cummins Marine corporate history and the dedicated Cummins QSK marine engine article.

Grammar

<series-prefix><displacement>[<rating-suffix>]

Series prefixes encode the architecture generation:

The number is engine displacement in litres or cubic inches depending on the era.

Worked examples

• QSK60-M: Quantum K-series, 60 litre displacement, marine duty rating M. 16 cyl V-bank.
• KTA38-M2: Legacy KTA, 38 litre, marine rating M2. 12 cyl V-bank.
• QSK95: Quantum K-series 95 litre flagship. 16 cyl V-bank, ~3,200 kW.
• QSL9: Light-commercial L-series, 9 litre, 6 cyl in-line.
• QSM11: Mid-range M-series, 11 litre, 6 cyl in-line.

MTU / Rolls-Royce MTU

MTU Friedrichshafen (now part of Rolls-Royce Power Systems, soon to be rebranded mtu Solutions under the Rolls-Royce demerger) makes high-speed and medium-high-speed 4-strokes for fast ferries, yachts, naval combatants, and emergency / pump-out gensets. The flagship Series 4000 sits on yachts up to 100 m and naval frigates up to 8,000 t. See MTU 4000-series marine engine and Rolls-Royce Power Systems / MTU corporate history.

Grammar

<cylinders>V<series>[M<rating>[<suffix>]]

Series numbers correspond to platforms: 2000, 4000, 8000, plus legacy 396, 595, 1163, 1600, 1800. The marine rating mark (M53, M63, M71, M73, M93, etc.) encodes power band and emissions tier.

Worked examples

• 16V4000M93: 16 cyl V-bank, Series 4000, M93 marine rating (highest-power, sprint duty).
• 20V4000M73: 20 cyl V-bank, Series 4000, M73 (continuous duty).
• 12V4000M53: 12 cyl V-bank, M53 commercial-marine.
• 20V8000M71: 20 cyl V-bank, Series 8000, M71 (frigate-class flagship).
• 8V2000M84: 8 cyl V-bank, Series 2000, M84 (workboat / patrol).
• 16V1163TB94: legacy Series 1163, B94 designation (1980s naval).

Volvo Penta

Volvo Penta has dominated the small-craft and mid-size commercial-vessel market since the 1960s with the D-series (D1 to D16) and the IPS (Inboard Performance System) pod-drive integrations. See Volvo Penta marine engines for the corporate and product history.

Grammar

D<displacement>[-<rating>]

The number after D is engine displacement in litres (D1 = 1L, D13 = 13L, D16 = 16L). The rating suffix gives output in metric horsepower at the maximum rating.

Worked examples

• D13-1000: D13 platform, 13 litre 6 cyl in-line, 1000 hp metric (~735 kW).
• D16-900: D16 flagship, 16 litre 6 cyl, 900 hp.
• D6-440: D6 platform, 5.5 litre, 440 hp. Common on yachts.
• D4-260: D4, 3.7 litre, 260 hp. Sail-cruiser auxiliary.
• IPS1050: D11 paired with the IPS pod drive at the 1050 hp rating.

Caterpillar 3500 / 3600

The Caterpillar 3500 series (3508, 3512, 3516) and 3600 series (3606, 3608, 3612, 3616) are heritage large-bore 4-strokes from Cat’s 1980s power-generation platform, widely deployed in workboat propulsion, OSV main engines, fishing vessels, and dredger gensets. See the Caterpillar 3500 marine engine article and the broader Caterpillar Marine corporate history.

Grammar

<series>[<rev>][HD]

The first two digits are the series; the second two digits encode the cylinder count (3508 = 8 cyl, 3512 = 12 cyl, 3516 = 16 cyl). Revision letters B, C, E mark generations within the series. HD denotes a heavy-duty (continuous-rated) version.

Worked examples

• 3516C: 3500 series, 16 cyl V-bank, C revision (Tier 3). 170 mm bore.
• 3512C: 12 cyl V-bank, C revision.
• 3508B: 8 cyl V-bank, B revision.
• 3616: 3600 series, 16 cyl V-bank. 280 mm bore. The largest Cat reciprocating marine engine.
• 3508C-HD: 3508C heavy-duty rating.

Caterpillar C-series

The Cat C-series (C7.1 to C280) is the modern successor to the legacy 3500/3600 line. The number after C is bore in litres (smaller engines) or in millimetres (larger C175, C280). See Caterpillar C280 marine engine.

Grammar

C<displacement-or-bore>[-<cylinders>]

Worked examples

• C32: 32 litre V-bank, 12 cyl. Yacht and patrol-boat sprint engine.
• C18: 18 litre 6 cyl in-line.
• C175-16: C175 platform (175 mm bore), 16 cyl V-bank.
• C280-12: C280 platform (280 mm bore), 12 cyl V-bank. Direct successor to the 3612.
• C280-16: C280, 16 cyl V-bank.

Hanshin Diesel

Japanese maker of medium-speed 4-strokes specialising in direct-drive coastal vessels (no reduction gearbox; engine speed = propeller speed). The LH-G, LH-L (long-stroke direct-drive) and LU series dominate Japanese coastal cargo and ferry fleets.

Grammar

<cylinders>(LH|LU|EL)<bore>[<variant>]

Variant suffix: G = gear-drive, L = long-stroke direct-drive, LG / LGS = lighter LG variants.

Worked examples

• 6LH28L: 6 cyl, 280 mm bore, long-stroke direct-drive.
• 6LH-G: 6 cyl, 260 mm bore, gear-drive variant.
• 6LU38: 6 cyl, 380 mm bore, LU series.
• 6LH40LG: 6 cyl, 400 mm bore, lightweight long-stroke.

Akasaka Diesel

Akasaka is the second major Japanese coastal-direct-drive maker, with the A (medium-speed), AH (heavy-duty long-stroke) and AK (compact-frame) series. See Akasaka Diesel marine engines.

Grammar

<cylinders>A<bore>[<variant>]

Worked examples

• 6A34C: 6 cyl, 340 mm bore, C variant.
• 6AH34: 6 cyl, 340 mm bore, AH heavy-duty long-stroke.
• 6A41S: 6 cyl, 410 mm bore, S variant.
• 6AK28: 6 cyl, 280 mm bore, AK compact.

Mitsubishi 4-stroke

Distinct from the Mitsubishi UEC 2-stroke programme, MHI produces a medium-speed 4-stroke family for tugs, OSVs, fishing vessels and gensets. The S6R and S12R marine variants are particularly common in tug propulsion. See the Mitsubishi UE engine family overview for the broader corporate context.

Grammar

S<cylinders><series-letter>[<mark>]

Series letters denote bore class: A3 (170 mm), B3 (180 mm), R / R2 (240 mm), Z (newest large-bore variant).

Worked examples

• S12R-MPTK: 12 cyl V-bank, R-series (240 mm bore), MPTK rating (high-output continuous).
• S6R2: 6 cyl in-line, R2 generation.
• S16R: 16 cyl V-bank, R-series.
• S12A2: 12 cyl V-bank, A2-series (smaller bore).
• S6B3: 6 cyl in-line, B3-series.

Doosan

Doosan Engine (now HD Hyundai Infracore) license-builds large MAN B&W 2-strokes for the Korean shipbuilding market and produces its own indigenous medium-speed 4-strokes (L126, L136, MD196, AD222, V222) for OSVs and fishing vessels.

Worked examples

• L126TI-D: in-line 6 cyl, 126 mm bore, turbocharged inter-cooled, D rating.
• MD196TI-D: 196 mm bore, marine duty.
• AD222LC: 222 mm bore, LC rating.
• V222TI-DM: V-bank 222 mm bore, marine duty.

Anglo Belgian Corporation (ABC)

ABC of Ghent makes mid-size medium-speed 4-strokes for tugs, dredgers, and harbour craft. The DXC, DZC and DL36 families dominate European coastal-fleet engine rooms. See the dedicated ABC DZC marine engine article.

Grammar

<cylinders>(DXC|DZC|DL36|DZD)[V|L]

Worked examples

• 6DZC: 6 cyl in-line DZC, 256 mm bore.
• 8DZC: 8 cyl in-line.
• 12DZC: 12 cyl V-bank.
• 6DXC: smaller DXC variant.
• DL36: 360 mm bore flagship.

Stork-Werkspoor

The legacy Dutch Stork-Werkspoor (later Stork-Wärtsilä, then absorbed into Wärtsilä) made the SW280, TM410, TM620 and F240 medium-speed series widely deployed on 1980s-1990s ferries and OSVs. See Stork-Werkspoor marine engines.

Worked examples

• SW280: Stork-Werkspoor 280 mm bore.
• TM410: 410 mm bore. Higher-output ferries.
• TM620: 620 mm bore. Slow-speed crosshead variant.
• 9SW280: 9 cyl in-line SW280.

Weichai / Yuchai / Zichai

The dominant Chinese 4-stroke makers, supplying domestic shipbuilding and increasingly the international workboat / fishing market. Weichai is the largest by volume; the Baudouin–Weichai marine engines article covers the joint venture lineage. Yuchai and Zichai focus on smaller-bore commercial. The licensed-MAN-B&W and licensed-Wärtsilä production by Chinese yards (Hudong-Zhonghua, Yichang Marine Diesel) is documented in CSSC marine engine subsidiaries and Mitsui E&S DU marine engines.

Worked examples

• X6170ZC: 6170 platform, ZC marine variant.
• 8170ZC: 8 cyl 170 platform.
• 12V190: 12 cyl V-bank, 190 mm bore.
• 6190ZLC: 6 cyl in-line, 190 platform, ZLC variant.

Scania Marine

Scania medium-speed marine engines (DI09, DI13, DI16) are the workhorse for fast ferries, patrol boats, and pilot boats in the 300-1,000 kW band.

Worked examples

• DI13-077M: DI13 platform (12.7 litre), 770 hp metric, marine duty.
• DI16-091M: DI16 (16.4 litre) 6 cyl in-line.
• DC09-072M: DC09 common-rail variant.

FPT / Iveco

FPT Industrial (Fiat Powertrain Technologies, formerly Iveco) supplies the NEF (4 cyl) and Cursor 9 / 13 / 16 (6 cyl) families to small-craft and workboat builders.

Worked examples

• C16-1000: Cursor 16, 16.1 litre 6 cyl, 1000 hp metric.
• C13-560: Cursor 13, 12.9 litre, 560 hp continuous.
• NEF-450: NEF 6 cyl, 6.7 litre, 450 hp.

John Deere PowerTech

John Deere PowerTech marine engines (4045, 6068, 6081, 6090, 6125, 6135) cover workboat propulsion and aux-genset duty up to ~750 kW.

Worked examples

• 6135HFM85: 6135 platform (13.5 litre), 6 cyl in-line, marine 85-rating (~485 kW continuous).
• 6090SFM85: 6090 (9.0 litre), marine.
• 6068TFM: 6068 (6.8 litre), turbocharged marine.
• 4045TFM: 4045 (4.5 litre), turbocharged marine.

Perkins Marine

Perkins (Caterpillar group) makes the Sabre M85 to M225Ti family for workboats and the smaller Perama M20-M35 for sail-cruiser auxiliaries.

Worked examples

• M225Ti: Sabre flagship, 225 hp turbocharged inter-cooled.
• M185C: Sabre 185 hp, common-rail.
• M135: Sabre 135 hp.
• M35: Perama, 35 hp small-yacht aux.

Yanmar high-speed

Distinct from the Yanmar EY/N medium-speed line, the Yanmar high-speed marine range (6LP, 6LPA, 6LY, 6LF) targets pleasure craft, sport-fishing, and small-commercial vessels. See Yanmar marine engines for the corporate context.

Worked examples

• 6LPA-STP2: 6LP common-rail 315 hp.
• 6LY3-ETP: 6LY 480 hp.
• 6LF-DTP: 6LF 380 hp.

Detroit Diesel

The legacy Detroit Diesel marine line covers the famous 2-stroke Series 71 and Series 92 (still operating on 1980s vintage tugs and fishing vessels worldwide), plus the 4-stroke Series 60 that succeeded them. See Detroit Diesel marine 71 / 92 series.

Grammar

<cylinders>V<series>[N|TIB|TI]

The series number 71, 92, 60 is fixed; cylinder count varies (4, 6, 8, 12, 16); turbo / aftercooler suffixes encode the rating.

Worked examples

• 8V71N: 8 cyl V, Series 71, naturally aspirated. Iconic harbour-tug engine.
• 12V71TI: 12 cyl V, Series 71, turbocharged inter-cooled.
• 16V92TA: 16 cyl V, Series 92, turbocharged aftercooled.
• Series 60 14L: 4-stroke 6 cyl in-line, 14 litre, marine variant.

GE aero-derivative gas turbines

Aero-derivative gas turbines are the dominant prime mover for warships and fast monohull / catamaran ferries, plus combined-cycle LNG-carrier propulsion. The GE LM-series is the market leader.

Grammar

LM<base-rating>[+G<gen>]

The base rating is the original aero-engine power class. The +G<gen> suffix marks the marine-marinised generation upgrades.

Worked examples

• LM2500: 25 MW class. Mainstay of US Navy DDG-51 destroyers and many cruise ships.
• LM2500+G4: 32 MW upgraded variant on the latest USN ships.
• LM6000: 50 MW class. Hybrid-electric and combined-cycle marine.
• LM500: 5 MW class for small naval / fast ferries.

Rolls-Royce MT-series

The MT30 is the highest-power marine gas turbine in production (~36 MW), used on the UK Type 26 frigate, US Navy LCS, and the Italian PPA-class.

Worked examples

• MT30: 36 MW class flagship.
• MT7: 4-5 MW, used on US Navy LCAC follow-on hovercraft.

Solar Turbines

Solar Turbines (Caterpillar subsidiary) makes industrial gas turbines used as marine prime movers in some FPSOs, accommodation barges, and combined-cycle plants on offshore vessels.

Worked examples

• Centaur-50: ~5 MW class.
• Taurus-60: ~5.5 MW.
• Mars-100: ~10 MW.
• Titan-130: ~14 MW.

Long-tail makers

Beyond the thirty-four makers documented above, the database also recognises designations from a number of regional and specialty manufacturers. Notable examples:

• Russian / Soviet: Kolomna D49, ZTM Penza M-503/M-504 high-speed naval, Bryansk 6CHN-series.
• Chinese indigenous: CSSC CHD-series, Anqing CSSC Diesel, Yichang Marine Diesel.
• Polish: Cegielski (license-built MAN B&W and Sulzer plus indigenous H-series).
• Indian: Kirloskar Oil Engines, Greaves Cotton, Cummins India.
• Historical European: see Mirrlees Blackstone, Crossley Brothers, Ruston, Paxman, English Electric, Cooper-Bessemer, Atlas Polar, NOHAB Polar, Bolinder, Doxford opposed-piston, Deutz.

Why a forgiving parser matters

Operators, surveyors and chandlers type engine designations into spreadsheets, emails, work orders and inspection reports many times a day. Real-world inputs rarely match the canonical typography:

• Capitalisation varies (6s60mc-c is common in informal correspondence).
• Dashes are inconsistent (6S60MCC versus 6S60MC-C versus 6S60 MC-C).
• Spaces appear at every position (6 S 60 MC C).
• Cylinder counts are sometimes elided when the context is a programme-level reference (UEC50LSE rather than 6UEC50LSE).
• Mark numbers are written with or without leading dashes (ME-C10.5 versus MEC10.5).

The live decoder calculator handles all these variations: it normalizes the input by uppercasing, collapsing whitespace, stripping dashes, then matches against each maker’s grammar in order. When the canonical form differs from what the user typed, the calculator surfaces a “normalized to” confirmation so the user knows which engine the system locked onto.

For unknown inputs, the calculator falls back to a Levenshtein-distance fuzzy suggestion against the database of known examples and surfaces the four nearest candidates as clickable suggestions. This handles typos and surfaces close-but-not-exact matches without forcing the user to remember the precise canonical typography.

Database scope and updates

The decoder’s database covers 34 makers with bore, stroke, output per cylinder and rated speed for the dominant model families within each maker’s programme: roughly 700 canonical model designations and 380 model families across two-stroke main propulsion, four-stroke medium-speed, four-stroke high-speed / small-craft, and aero-derivative gas turbines. The database is versioned (current: v2026.05.07) and refreshed periodically as makers release new variants.

The full live decoder is at the Marine Engine Model Decoder calculator.

Related resources

Additional calculators:

• System - Auxiliary Engine: Medium-speed 4-stroke
• Mean Piston Speed
• System - Emergency Genset: High-speed diesel

Additional formula references:

• Engine Volvo Penta D16 Ips 900
• System Auxiliary Engine Medium Speed 4 Stroke
• Engine Volvo Penta D13 800
• Engine Volvo Penta D16 Mh Mg

Additional related wiki articles:

• Four-Stroke Marine Diesel Engine Fundamentals
• Marine Auxiliary Engines and Generators
• HiMSEN Medium-Speed Marine Engines (Hyundai)

Calculators that use engine designation as input

• EEDI Attained calculator: IMO Energy Efficiency Design Index, parameterised by main engine bore, stroke and rated power.
• EEXI Attained calculator: the in-service equivalent applied to existing ships at MEPC 76.
• CII Attained calculator: annual carbon-intensity rating, dependent on main engine SFOC.
• EU ETS EUA Liability calculator: allowance surrender, parameterised by engine fuel consumption and carbon factor.
• SFOC sensitivity calculator: converts engine fuel-consumption deltas into BSFC and emissions changes.
• Admiralty power calculator: first-pass shaft power required for a given displacement and speed.
• The full calculator catalogue.

Background reading on engine architecture

• Two-stroke marine diesel engine fundamentals
• Crosshead diesel engine architecture overview
• Trunk-piston engine architecture
• Medium-speed four-stroke marine engines
• Uniflow scavenging in two-stroke marine engines
• Common-rail fuel injection on two-stroke engines
• Pilot injection in dual-fuel engines
• Tier III compliant two-stroke engines
• SCR retrofit on two-stroke engines
• EGR retrofit on two-stroke engines
• Methanol marine engines overview
• Ammonia marine engines overview
• Engine load diagram and operating envelope
• Engine performance monitoring (PMI)
• Marine engine turbocharging
• Engine derating for slow steaming
• Slow steaming and engine cleanliness
• Two-stroke engine future developments

Sources

• MAN Energy Solutions: Two-stroke engine programme and Four-stroke marine engines.
• WinGD: Engine programme and X-DF technology overviews.
• Wärtsilä: Marine engines and generating sets.
• MHI-MME: UEC engines.
• Hyundai Heavy Industries: HiMSEN engines.
• Caterpillar Marine: M-Series engines.
• Bergen Engines: Marine engine portfolio.
• Daihatsu Diesel: Marine engines.
• Niigata Power Systems: Product portfolio.
• Yanmar: Marine commercial engines.
• Wikipedia: MAN B&W ME-C, Wärtsilä-Sulzer RTA96-C.