Marine Engine Model Numbers: Naming Conventions by Maker

Live decoder calculator: the companion Marine Engine Model Decoder calculator parses any model string (for example 6S60MC-C, 8G80ME-C10.5, 12X92DF, 9L48/60CR, B33:45L9, 8RT-flex96C, 6UEC50LSJ, 7K98MC) and renders the per-character breakdown (maker, cylinder count, stroke prefix, bore, generation, fuel system) in real time. Forgiving input: capitalization, whitespace, dashes and brand names in front (HiMSEN H21/32) are all normalized; the decoder runs Levenshtein fuzzy match against every known example when no parser produces a confident hit. Use it alongside this article when working with builder’s nameplates, classification certificates or technical files.

Why engine designations are structured

Marine engine programs 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 under MARPOL Annex VI, engine builders’ licenses 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 EEDI Attained calculator and the EEXI Attained calculator both consume engine designations to look up reference NOx and SFOC values that determine compliance.

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. Where appropriate the article traces the lineage from each maker’s first marine 2-stroke through the current alternative-fuel variants, so that an engineer reading an older nameplate (such as a 1970s 9K45GFC) can locate the engine on the family tree and identify its modern descendant.

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 programs merged in 1980 under the MAN B&W Diesel banner, and the unified program has been progressively rebranded since: MAN Diesel (2006), MAN Diesel & Turbo (2010), MAN Energy Solutions (2018), and most recently Everllence (4 June 2025) as the corporate identity. The engines themselves continue to be marketed as MAN B&W and B&W, and that nameplate remains the canonical reference on classification certificates, builder’s nameplates and the live decoder calculator. The current marine program is licensed for series production by Hyundai Heavy Industries (HHI) in Korea, Mitsui E&S Machinery in Japan, Doosan Engine in Korea, Dalian Marine Diesel and Hudong-Zhonghua in China, and others; together these licensees account for an estimated 70 to 80 percent of large 2-stroke engines on order. See the MAN Energy Solutions corporate history wiki for the corporate-rebrand and licensing chronology.

Grammar (modern program)

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

For example, 6S60MC-C parses as:

Stroke prefix

Lineage and type codes

The B&W 2-stroke program has gone through eight major generations since the mid-1960s. Older nameplates use the legacy codes; the modern program uses MC and ME variants. The full lineage:

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). The current Mark numbers on the G-series flagship reach Mark 10.5 and 11.0, depending on bore. See the marine engine model decoder calculator for instant mark-aware lookups and the BMEP calculator for the mean-effective-pressure context that drives mark progression.

Worked examples

• 9K45GFC: 9 cyl, short stroke, 450 mm bore, GFC generation. Mid-1970s mechanical engine with constant-pressure turbocharging. Still operating on 1970s-vintage bulk carriers and licensed Mitsui-built tonnage; the modern successor in the same bore class is the 6G45ME-C9 or 6S46ME-B8.
• L80GFCA: bare-platform reference to the L80-bore fuel-economy-tuned GFCA generation (1978-1982). Common on older tankers; survivor numbers shrinking but plenty still in service.
• 6S60MC-C: 6 cyl, super-long stroke, 600 mm bore, MC compact. Legacy program, 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).
• 6S35ME-LGIM: 6 cyl, super-long stroke, 350 mm bore, methanol dual-fuel. Methanol-ready newbuild container feeders and Stena RoRo program.
• 8G70ME-GIE: ethane-fueled ME-GI for VLECs.
• 6G70ME-LGIP: LPG-fueled ME-LGI for VLGCs.
• 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 overview, uniflow scavenging, common-rail fuel injection on two-stroke engines, exhaust valve actuation in two-stroke engines, tier III compliant two-stroke engines, methanol marine engines overview and ammonia marine engines overview.

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 program is the X-series, which replaced the older RT and RT-flex families, with a rapidly expanding family of dual-fuel and alternative-fuel derivatives. WinGD’s 2-stroke business is the principal competitor to MAN B&W / Everllence for large slow-speed orders, with the recent X-DF generations winning a disproportionate share of LNG-fueled container-ship newbuilds. See the WinGD corporate history for the spin-off and CSSC-ownership chronology, and the in-depth WinGD X-DF dual-fuel architecture wiki for the technical detail.

Grammar (modern X-series)

<cylinders>X<bore cm>[DF][-<fuel M|A|P|HP>]-[S]<technology level>.<update level>

WinGD’s 2026 engine booklet gives the legend with the example 6X52DF-A-S1.0: six cylinders, X-series, 52 cm bore, dual fuel, ammonia, short stroke, technology level 1, update 0. Diesel engines carry the version without DF (10X92-1.1, 6X62-S2.0); the first X-DF engines carried no version (12X92DF). Older engines carry a letter mark (X35-B, X92-B) whose meaning WinGD doesn’t state.

Variant suffixes

Lineage and predecessors

The X-series itself replaced the Sulzer/Wärtsilä RT-flex (2001-2015), which replaced the RTA (1990s-2000s), which replaced the RT (1980s-1990s). The full Sulzer pre-RT lineage runs RD (1965-1980s, conventional camshaft with loop scavenging) → RND (1968-1980s, stretched-stroke uniflow with single exhaust valve) → RND-M (1980-1990s, higher MEP) → RLA (1977-1990s, the smaller-end long-stroke program) → RLB (1985-1995, higher-output RLA derivative). These older Sulzer engines are documented under the Wärtsilä 2-stroke (Sulzer / RT) section below; the WinGD section here covers the X-series only.

Worked examples

• 8X92DF: 8 cyl, X92 platform (920 mm bore), dual-fuel LNG. Flagship for 23,000+ TEU LNG-fueled container ships.
• 7X62DF-S2.0: 7 cyl, 620 mm bore, LNG dual-fuel, short stroke, technology version 2.0.
• 10X92-1.1: 10 cyl, 920 mm bore, diesel, version 1.1, 6,450 kW per cylinder.
• 7X82: 7 cyl, 820 mm bore, conventional oil-fueled.
• 8X82DF-HP-1.0: 8 cyl, 820 mm bore, high-pressure LNG (2028 deliveries).
• 5X52DF-A-1.0: 5 cyl, 520 mm bore, ammonia-fueled.
• 5X62DF-P-1.0: 5 cyl, 620 mm bore, LPG with ammonia-ready pre-fit.
• 6X62DF-M-1.0: 6 cyl, 620 mm bore, methanol-fueled.

The X-series is gradually displacing the legacy RT-flex on newbuilds; the smaller bores (X35, X40) entered series production from approximately 2018. WinGD’s alternative-fuel roadmap is now broader than MAN’s at the same bore class, particularly the X-DF-P pre-fit concept that monetizes both LPG cargo trades and the eventual ammonia transition without requiring two separate hull designs.

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 programs until the 2015 spin-off to WinGD. The designation lineage is sometimes called “Sulzer RT” interchangeably with “Wärtsilä RT”. The pre-RT Sulzer slow-speed program dates back to the 1930s.

Grammar

Worked examples

• 6RD76: 6 cyl Sulzer RD76 (760 mm bore). Mid-1970s flagship for VLCCs of the era.
• 7RND68M: 7 cyl RND68 with the M revision (680 mm bore, late period).
• 5RLA90: 5 cyl RLA90 (900 mm bore long-stroke).
• 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. The handful of overhaul yards still supporting RD and RND parts are concentrated in Hong Kong, Busan and Rotterdam. See Sulzer marine diesel engines history and Wärtsilä corporate history.

Mitsubishi UEC

Japan Engine Corporation (J-ENG) designs and sells the UE two-stroke crosshead engines that Mitsubishi Heavy Industries developed. J-ENG was formed in 2017 when Kobe Diesel merged with the marine engine business of Mitsubishi Heavy Industries Marine Machinery & Engine. J-ENG’s catalog expands UEC as Uniflow scavenging, Exhaust gas turbocharger, Crosshead. The 2026 catalog lists bores from 33 to 80 cm.

Grammar

<cylinders>UEC<bore cm><series>[-Eco][-<BMEP letter><SFOC version>][-<Tier III>]

For example 7UEC60LSH-Eco-C3-HPSCR is seven cylinders, 600 mm bore, LSH series, electronically controlled, BMEP class C with SFOC version 3, and high-pressure SCR for Tier III.

Series and suffix codes

J-ENG writes the Roman numeral as a single character on its web pages (UEC33LSⅡ); the decoder reads it as LSII. The codes LSGI, LSC and HC that appear in some secondary lists don’t appear in J-ENG’s catalog, line-up or history.

Worked examples

• 6UEC50LSJ-EGR: 6 cyl, 500 × 2,300 mm, LSJ series, low-pressure EGR. 1,780 kW per cylinder at 108 rpm.
• 7UEC50LSJA-HPSCR: 7 cyl, 500 mm bore, ammonia dual-fuel, high-pressure SCR.
• 7UEC80LSE-Eco: 7 cyl, 800 × 3,150 mm, 4,440 kW per cylinder at 80 rpm, electronically controlled.
• UEC33LSII: 330 × 1,050 mm, 566 kW per cylinder at 215 rpm.
• 6UEC52LA: 6 cyl, legacy LA series, 520 × 1,600 mm.
• 6UEC60LS: 6 cyl, legacy LS series, 600 × 2,200 mm, 1,770 kW per cylinder at 100 rpm.

See Mitsubishi UE and UEC two-stroke engines for the history.

MAN 4-stroke

The MAN 4-stroke program spans medium-speed engines from 160 mm (L16/24) to 510 mm (51/60DF) bore in the Everllence Marine Engine Programme 2026. 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 type name gives bore/stroke in centimeters separated by a slash, as the key in the Everllence Marine Engine Programme 2026 states (“Bore in cm / Stroke in cm”): 48/60 is 480 mm bore and 600 mm stroke. The one exception is the high-speed 175D, where 175 is the bore in millimeters. The 58/64 is not in the 2026 program.

Grammar

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

Configurations

Suffixes

Worked examples

• 9L48/60CR: 9 cyl, in-line, 480/600 mm bore/stroke, common-rail. 1,200 kW per cylinder at 514 rpm (Everllence 2026).
• 12V32/44CR: 12 cyl, V-bank, 320/440 mm, 600 kW per cylinder at 750 rpm.
• 12V28/33D STC: 12 cyl, V-bank, 280/330 mm, distillate fuel, sequential turbocharging.
• 16V175DF-M: 16 cyl vee, 175 mm bore, methanol dual-fuel, up to 2,720 kW (170 kW per cylinder) at 1,800 rpm; the 12V and 20V reach 190 kW per cylinder (Everllence 175DF-M fact sheet, 2026).
• 12V175D-MM: the diesel 175D with a rating code after the dash; Everllence uses MH, MM and ML for propulsion duty and MEL, MEM, MEV and MA for generator sets.
• 6L27/38 Mk 2: 6 cyl, 270/380 mm, second design mark, 410 kW per cylinder at 900 rpm.
• 9L21/31: 9 cyl, in-line, 210/310 mm. Small aux genset.
• 8L51/60DF: 8 cyl, 510/600 mm, dual-fuel LNG.
• 9L49/60DF: 9 cyl, 490/600 mm, dual-fuel LNG, 1,300 kW per cylinder at 600 rpm.
• 6L21/31DF-M: 6 cyl, 210/310 mm, methanol dual-fuel. Auxiliary genset for methanol-fueled container ships and gas carriers.
• 6L35/44DF CD: 6 cyl, 350/440 mm, dual fuel with the CD appendix.

For dedicated articles see MAN 32/40 medium-speed engine, MAN 48/60 medium-speed engine, MAN L21/31 medium-speed engine and MAN L32/44CR medium-speed engine. For the broader 4-stroke architecture see medium-speed four-stroke marine engines and trunk-piston engine architecture.

Wärtsilä 4-stroke

Wärtsilä’s four-stroke engines are named by bore in centimeters, from the W20 (200 mm) to the W46 (460 mm) in the current marine range, with older W14, W26, W38, W50DF and W64 engines and the Vasa 22 and 32 still in service. They are used for medium-speed main propulsion (cruise ships, ferries, RoRo, OSV), generator sets and dual-fuel LNG carrier propulsion. The Stork-Werkspoor SW38 was continued as the Wärtsilä 38.

Grammar

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

Wärtsilä’s product guides write individual engines with the W in front and a space (W 6L46F, W 12V32); brochures drop it (6L20, 12V46TS). The stroke is never in the name: the W32 is 320 × 400 mm and the W46F 460 × 580 mm.

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.

Current marine program

Wärtsilä’s marine engines page lists these four-stroke types:

The W14, W26, W38, W50DF and W64 are no longer on that page but remain in service and decode.

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.
• 8L31DF: 8 cyl, 310 mm bore, dual-fuel.
• 6L25DF: 6 cyl, 250 mm bore, dual-fuel (new Wärtsilä 25 platform).
• 6L32-Methanol: 6 cyl, 320 mm bore, methanol-fueled.
• 16V46TS-DF: 16 cyl V-bank, 460 mm bore, Tier-compliant dual-fuel.

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

Hyundai HiMSEN

HiMSEN (Hi-touch Marine & Stationary ENgine) is HD Hyundai Heavy Industries’ own four-stroke medium-speed program, built by its Engine & Machinery Division at Ulsan since August 2000. The 2026 HiMSEN program runs from the 170 mm bore H17/28 to the 540 mm bore H54DF, on diesel and HFO, LNG dual fuel, spark-ignition gas, methanol and ammonia. HiMSEN gives bore and stroke in centimeters, as MAN does, but writes the vee letter after the bore and stroke rather than before. See the HHI Engine & Machinery Division article for the company and the HiMSEN article for the full program.

Grammar

HHI’s designation key (2026 program, p.11) is 18 H 32 / 40 _ V P - LM. In general form:

[<cylinders>]H<bore cm>/<stroke cm>[G][V][P]

[<cylinders>]H<bore cm><type>[V][P][-LM|-LA]

On the second form a type code stands in for the stroke, so 7H21C doesn’t say that its stroke is 330 mm.

HHI’s 2010 catalog used application letters after the stroke instead: (M) marine generator set, (P) propulsion, (S) stationary. A plate reading 6H21/32P or 9H25/33(M) dates from that convention.

Program families

The H35CDF, a second-generation Clean-platform LNG dual-fuel engine, passed its type approval test on 21 to 23 September 2026; HHI hasn’t yet published its stroke or ratings, so the decoder gives its 350 mm bore only.

H22/26, H27/38, a diesel H35/40, H46DF and H46/60DF appear in some third-party lists but in neither HHI’s 2010 catalog nor its 2026 program. The decoder reads their grammar but returns no rating for them.

Worked examples

• 6H21/32: 6 cylinders, in-line, 210 mm bore, 320 mm stroke, generator rating. Up to 220 kW per cylinder at 1,000 rpm, 1,320 kW for the engine.
• HiMSEN H21/32 or HiMSEN Diesel Engine H21/32: the same platform with the brand written in front and no cylinder count. The decoder drops the brand and decodes the platform.
• 18H32/40V: 18 cylinders, vee, 320 × 400 mm. At 500 kW per cylinder, 9,000 kW.
• 12H32/40VP: 12 cylinders, vee, propulsion rating at 750 rpm.
• 7H21C: 7 cylinders, Clean platform, 210 × 330 mm, 240 kW per cylinder.
• 9H35DF: 9 cylinders, 350 × 400 mm, LNG dual fuel; 4,320 kW as a generator set, 4,500 kW as the propulsion 9H35DFP.
• 6H22CDFP-LM: 6 cylinders, 220 mm Clean dual-fuel platform, propulsion rating, liquid methanol.
• 9H32CDF-LA: 9 cylinders, H32C platform, liquid ammonia, 5,400 kW.
• 12H54DFV TSTC: 12 cylinders, 540 × 600 mm, LNG dual fuel, vee, two-stage turbocharged, 16,800 kW.

MaK / Caterpillar

MaK engines are built by Caterpillar Motoren in Kiel. Cat literature writes the type with spaces: cylinder count, M for an in-line or VM for a vee engine, the bore in centimeters, then a generation letter or DF (6 M 25 E, 12 VM 43 C, 9 M 34 DF). The Cat Marine Power Solutions guide lists M 20 C, M 25 E, M 32 C, M 32 E, VM 32 E, M 34 DF, M 43 C, VM 43 C and M 46 DF; older types (M 453, M 551, M 552, M 601) used a three-digit code.

Grammar

<cylinders> (M|VM) <bore cm> <C|E|DF>

Suffixes

Worked examples

• 6M32C: 6 cyl, 320 × 480 mm, 500 kW per cylinder at 600 rpm.
• 9M43C: 9 cyl, 430 × 610 mm, 1,050 kW per cylinder at 514 rpm.
• 12 VM 43 C: 12 cyl vee, same cylinder as the M 43 C.
• 8M46DF: 8 cyl, 460 × 610 mm, dual-fuel, 965 kW per cylinder at 514 rpm.
• 9 M 34 DF: 9 cyl, 340 × 460 mm, dual-fuel, 550 kW per cylinder at 750 rpm.

For the MaK history see MaK Maschinenbau Kiel marine engines and Caterpillar Marine corporate history. Caterpillar’s own 3500 and 3600 series use a different grammar; see the Caterpillar 3500/3600 section below.

Daihatsu Diesel

Daihatsu Infinearth (formerly Daihatsu Diesel) builds medium-speed four-strokes from 165 to 360 mm bore for generator sets and geared propulsion, with a dual-fuel line on the DE platform. The two digits after the hyphen are the bore in centimeters, rounded: the DE-18 has a 185 mm bore and the DE-28 a 285 mm bore.

Grammar

<cylinders><series>[M]-<bore cm>[A][e] and <cylinders>DE<bore cm>DF

Worked examples

• 6DK-28e: 6 cyl, 280 × 390 mm, up to 360 kW per cylinder at 750 rpm.
• 8DC-32e: 8 cyl, 320 × 400 mm, 500 kW per cylinder at 720 rpm.
• 6DE-18: 6 cyl, 185 × 280 mm.
• 6DE28DF: 6 cyl, DE-28 platform, dual fuel.

See Daihatsu Infinearth marine engines.

Niigata Power Systems

NIIGATA engines are built by IHI Power Systems, part of the IHI group. The medium-speed range is the HX series (19 to 41 cm bore) and its successor the AHX, with a 28AHX-DF dual-fuel version; IHI also lists low-speed M-type and high-speed NSD and FX engines. The number before the series code is the bore in centimeters, rounded: the 17HX has a 165 mm bore.

Grammar

<cylinders>(MG|L|V)<bore cm><series>[-DF]

Worked examples

• 6L28AHX: 6 cyl in-line, 280 × 390 mm. The 28AHX reaches 370 kW per cylinder at 800 rpm as a propulsion (MG) engine; generator versions run at 720 or 750 rpm at lower ratings.
• 12MG28AHX: 12 cyl propulsion version of the same cylinder.
• 9L28AHX-DF: 9 cyl, dual fuel, 320 kW per cylinder.
• 6MG26HLX: 6 cyl, 260 × 350 mm.
• 16V20FX: 16 cyl vee, 205 × 220 mm, 1,650 rpm.

See Niigata Power Systems marine engines.

Yanmar

Yanmar’s medium-speed marine range is the EY series (EY17 to EY33) for propulsion and generator duty, alongside the N21, N165 and NY16. The number is the bore in centimeters for EY, N21 and NY16, but in millimeters for N165. Propulsion versions end in W; generator versions in LW.

Grammar

<cylinders>EY<bore cm>[A][L]W and <cylinders>N<bore>[A|L]-<grade>W

Worked examples

• 6EY26W: 6 cyl propulsion, 260 × 385 mm, 320 kW per cylinder at 750 rpm.
• 6EY22ALW: 6 cyl generator, 220 × 320 mm, higher-speed version.
• 8EY33LW: 8 cyl generator, 330 × 440 mm.
• 6N21A-SW: 6 cyl, 210 × 290 mm (bore in cm).
• 6N165L-SW: 6 cyl generator, 165 mm bore (bore in mm).

See Yanmar marine engines for the company history; for Yanmar’s high-speed pleasure and workboat engines see the Yanmar high-speed section below.

Bergen / Rolls-Royce

Bergen Engines AS of Norway makes medium-speed four-strokes for offshore vessels, gas-fueled ferries and power plants. Rolls-Royce owned it until 2021, when it was sold to Langley Holdings. Bergen writes bore:stroke in centimeters separated by a colon, which identifies its engines at a glance.

Grammar

<B|C><bore cm>:<stroke cm><L|V><cylinders>[ ]<P|A>

Worked examples

• B33:45L9P: 330 × 450 mm, in-line, 9 cyl, propulsion. 600 kW per cylinder at 750 rpm.
• B36:45V12 A: 360 × 450 mm gas engine, vee, 12 cyl, generator set.
• C25:33L9P: 250 × 330 mm, in-line, 9 cyl, propulsion, 333 kW per cylinder at 1,000 rpm.
• C26:33L6A: 260 × 330 mm gas engine, 6 cyl, generator set.

See the Bergen B33:45 article for the most-built model.

Pielstick / SEMT-Pielstick

S.E.M.T. Pielstick of France developed the PA (high-speed) and PC (medium-speed) four-strokes from the 1950s; the brand passed to MAN Diesel and so to Everllence, whose 2026 program still lists the PA6B, PA6B STC and PC2.6 B. See the SEMT-Pielstick engines article for the corporate history.

Grammar

<cylinders>PA<n>[ <L|V> <bore mm>][ <variant>] and <cylinders>PC<n>-<mark>[B][<L|V>]

The number after PA or PC is a type, not a bore; where the bore is written it follows the configuration letter in millimeters (8 PA4 V 200 SM, 12 PA6 V 280). B marks the improved-performance version, which lengthens the stroke: 330 mm on the PA6B, 500 mm on the PC2-6B, 660 mm on the PC4-2B. STC is sequential turbocharging; CL is the long-stroke PA6 (350 mm).

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

• 12PC2-6B: 12 cyl vee, 400 × 500 mm, 750 kW per cylinder at 600 rpm.
• 16PA6 B STC: 16 cyl, 280 × 330 mm, B version with sequential turbocharging, 405 kW per cylinder at 1,050 rpm.
• 12PC2-5V: 12 cyl vee, 400 × 460 mm, 485 kW per cylinder at 520 rpm.
• 6PA6CL: 6 cyl, 280 × 350 mm long-stroke PA6.
• 10PC4-2B: 10 cyl vee, 570 × 660 mm, the largest Pielstick at 1,400 kW per cylinder at 430 rpm.

Cummins Marine

Cummins marine propulsion runs from the 6.7 L QSB6.7 to the 95.3 L V16 QSK95, with the mechanical K-series (KTA19, KTA38, KTA50) and the NTA855 still in the commercial catalog. The number is the displacement in liters. See Cummins QSK marine engine.

Grammar

<family><displacement L>[-<application>[<build number>]]

Each rating carries a Cummins duty definition (Continuous, Heavy Duty, Medium Continuous, Intermittent) printed beside it, not in the model name.

Worked examples

• QSK60-M: V16, 159 × 190 mm, 60 L, marine propulsion.
• QSK95: V16, 190 × 210 mm, 95.3 L, up to 195.8 kW per cylinder at 1,700 rpm.
• KTA38-M2: V12, 159 × 159 mm, legacy mechanical engine, build variant 2.
• X15-DM: in-line 6, 137 × 169 mm, fixed-speed auxiliary.
• QSB6.7: in-line 6, 107 × 124 mm.

MTU / Rolls-Royce MTU

mtu (Rolls-Royce Solutions, Friedrichshafen) builds the high-speed Series 2000, 4000, 1163 and 8000 for fast vessels, yachts, naval craft and generator sets; Series 396 and 595 remain in service on 1990s yachts and ferries. See MTU 4000-series marine engine.

Grammar

[MG]<cylinders>V<series>M<segment><design index>[<letters>]

mtu prints it with spaces as well (16 V 4000 M73 L). The digits after M are an application segment and a design index, not a rating; mtu rates each model for an application group in its Marine and Offshore Solution Guide.

The generation matters for the geometry. The first-generation Series 2000 (M60, M70, M90) is 130 × 150 mm and the current one 135 × 156 mm; the first-generation Series 4000 is 165 × 190 mm, the current standard-stroke 170 × 190 mm and the long-stroke 170 × 210 mm.

Worked examples

• 16V4000M73L: 16 cyl vee, Series 4000-03, 170 × 190 mm, power uprated; 20V 4000 M73L is 3,600 kW at 2,050 rpm in group 1B.
• 20V4000M65L: 20 cyl vee, long-stroke Series 4000, 170 × 210 mm; 3,200 kW at 1,800 rpm, group 1A.
• 16V4000M90: first-generation Series 4000, 165 × 190 mm.
• 16V2000M96L: 16 cyl vee, 135 × 156 mm, 1,939 kW, group 1DS.
• 20V8000M91L: 20 cyl vee, Series 8000, 265 × 315 mm.
• MG16V4000M33S: marine generator set, 60 Hz.

The decoder reports the bore and stroke for MTU engines and leaves the kW to the model’s own spec sheet, because one series spans several application groups.

Volvo Penta

Volvo Penta’s commercial marine range runs from the D3 (2.4 L, five cylinders) to the D16 (16.1 L, six cylinders). Leisure models carry the crankshaft horsepower in the name; commercial inboards carry MH for propulsion or MG for a generator set.

Grammar

D<platform>-<crank hp>, D<platform> MH|MG, D<platform>-IPS<number>

Worked examples

• D13-900: D13 platform, 131 × 158 mm, 900 crankshaft hp.
• D16 MH: D16, 144 × 165 mm, commercial propulsion.
• D9 MG: D9, 120 × 138 mm, generator set.
• D6-435WJ: D6, waterjet version.
• D7A TA: legacy D7, turbocharged aftercooled.

Caterpillar 3500 / 3600

The Cat 3500 family is a 170 mm bore V8, V12 and V16 built with a 190 mm stroke and, in the HD versions, a 215 mm stroke. The 3600 family (280 × 300 mm) was followed by the C280. See the Caterpillar 3500 marine engine article.

Grammar

35<cylinders, two digits>[B|C|E][ HD] and 36<cylinders>

Worked examples

• 3516C HD: 16 cyl vee, 170 × 215 mm, C generation.
• 3512E: 12 cyl vee, 170 × 215 mm, Tier III generation, 158.5 kW per cylinder at 1,800 rpm.
• 3508B: 8 cyl vee, 170 × 190 mm, B generation.
• 3606: 6 cyl in-line, 280 × 300 mm, 2,030 kW at 1,000 rpm on marine diesel (Cat 3600 guide LEKM8461); the 3608, 3612 and 3616 run 2,710, 4,060 and 5,420 kW.
• 3516E High Output: 16 cyl vee, 3,000 kW at 1,800 rpm on a D rating.

Caterpillar C-series

Cat C-series names give the approximate displacement in liters (C7.1, C9.3, C12, C18, C32); C175 and C280 give the bore in millimeters, followed by the cylinder count.

Grammar

C<displacement L>[ ACERT][B] and C<bore mm>-<cylinders>

Worked examples

• C32 ACERT: V12, 145 × 162 mm.
• C32B: the later C32, 1,790 kW at 2,300 rpm on an E rating.
• C18 ACERT: in-line 6, 145 × 183 mm.
• C175-16: V16, 175 × 220 mm.
• C280-8: in-line 8, 280 × 300 mm, a medium-speed engine at 900 to 1,000 rpm, 338.75 kW per cylinder.

Hanshin Diesel

Hanshin Diesel Works of Kobe builds low-speed four-stroke main engines for Japanese coastal ships, six-cylinder in its current range, plus the MX28 medium-speed engine. The two digits are the bore in centimeters. Hanshin also builds MAN B&W two-strokes under license (S30ME-B9, S35ME-B9, S35MC7). See Hanshin Diesel marine engines.

Grammar

L(H|A)<bore cm>[A][L|G][E|M], G<bore cm> and <cylinders>MX<bore cm>

Worked examples

• LH28G: 6 cyl, 280 × 460 mm, reversing gearbox, 171.5 kW per cylinder at 395 rpm.
• LH46LA: 6 cyl, 460 × 880 mm, long stroke, higher rating.
• LA28M: 6 cyl, 280 × 590 mm, methanol.
• G30: 6 cyl, 300 × 720 mm, LNG spark ignition.
• 6MX28: 6 cyl medium-speed, 280 × 380 mm, 730 rpm.

Akasaka Diesel

Akasaka Diesels of Yaizu builds low-speed four-stroke main engines in the A, AX, AT, K, E and AH types, all six-cylinder in-line, and the medium-speed U type in six and eight cylinders. The digits are the bore in centimeters. Akasaka has built Mitsubishi UEC two-strokes under license since 1960. See Akasaka Diesel marine engines.

Grammar

<type><bore cm>[letters][R|D|FD|ED] for the six-cylinder types, written without a cylinder count, and <cylinders>U<bore cm>AK for the U type.

Worked examples

• A41: 410 × 800 mm, 2,427 kW at 230 rpm (404.5 kW per cylinder); the A41S is 2,647 kW at 240 rpm.
• A45S: 450 × 880 mm, higher rating, 551.5 kW per cylinder at 220 rpm.
• AX33B: 330 × 620 mm.
• 6U28AK: 6 cyl medium-speed, 280 × 380 mm, 720 rpm.

Mitsubishi 4-stroke

Separate from the J-ENG UEC two-strokes, Mitsubishi Heavy Industries Engine & Turbocharger builds high-speed and medium-speed four-strokes at Sagamihara. The series letter doesn’t encode the bore: an S6R is 170 × 180 mm and an S6U 240 × 260 mm.

Grammar

S<cylinders><series>[rev]-[T2]<cooling code>[rev]

Mitsubishi’s own example is S 6 R2 - T2 MPTAW 3L.

Worked examples

• S6R2-T2MPTK3: 6 cyl, R2 series, 170 × 220 mm, Tier II, seawater-cooled charge air, revision 3.
• S12R-MPTK: 12 cyl, R series, 170 × 180 mm, 100.8 kW per cylinder at 1,800 rpm.
• S16R-MPTAW: 16 cyl, R series, freshwater-cooled charge air.
• S6U-MPTK: 6 cyl, U series, 240 × 260 mm, 186.5 kW per cylinder at 1,100 rpm.

Doosan

Two companies carry the Doosan name in older documents. Doosan Infracore, now the engine business of HD Hyundai, builds high-speed marine diesels. Doosan Engine, now Hanwha Engine, builds MAN B&W and WinGD two-strokes under license; those engines carry the licensor’s designation and decode under MAN B&W or WinGD. See the Hanwha Engine corporate history.

Grammar

[4]<L|V|AD|MD><code>[T|TI|C]

The numeric code is not a bore. T means turbocharged, TI turbocharged and intercooled, and no letter naturally aspirated. AD models are the marine auxiliary versions.

Worked examples

• L136TI: 6 cyl in-line, 111 × 139 mm, turbocharged and intercooled, propulsion.
• 4V158TI: V8, 128 × 142 mm.
• 4V222TI: V12, 128 × 142 mm, 73.6 kW per cylinder at 2,300 rpm.
• AD126TI: 6 cyl auxiliary engine, 123 × 155 mm, 1,800 rpm.

Anglo Belgian Corporation (ABC)

ABC of Ghent builds three platforms: DZ (256 mm bore, in-line DZ and vee VDZ, with dual-fuel, methanol and hydrogen versions), D36 (365 mm bore, DL36 and DV36) and E23 Evolve (230 mm bore, EL23 and EV23). See the ABC DZC article.

Grammar

<cylinders>D(L|V)36, <cylinders>E(L|V)23, <cylinders>[V]DZ[C|D], and the product-guide key <cylinders> DZ - <rpm> - <BMEP × 10> - <A|K>

The product-guide key reads 6 DZ - 1000 - 166 - A: six cylinders, DZ type, 1,000 rpm, 16.6 bar BMEP, counter-clockwise rotation (A; K is clockwise).

Worked examples

• 6DZC: 6 cyl, 256 × 310 mm, 234 kW per cylinder at 1,000 rpm.
• 16VDZC: 16 cyl vee DZ.
• 8DL36: 8 cyl, 365 × 420 mm, 659 kW per cylinder at 750 rpm.
• 20EV23: 20 cyl vee, 230 × 310 mm, 360 kW per cylinder at 1,200 rpm.
• 8DZ DF MeOH: 8 cyl DZ, methanol dual fuel.

Stork-Werkspoor

Stork-Werkspoor Diesel of the Netherlands built medium-speed engines now out of production and supported by QuantiParts, a Wärtsilä company. The designation puts the cylinder count before the type, and the number is the bore in millimeters (6 SW 280, 12 TM 410). The SW38 was continued as the Wärtsilä 38. See Stork-Werkspoor marine engines.

Worked examples

• 8SW280: 8 cyl, 280 mm bore.
• 12 TM 410: 12 cyl vee, 410 mm bore.
• 9TM620: 9 cyl in-line, 620 mm bore, a medium-speed trunk-piston engine.
• 6F240: 6 cyl, 240 mm bore.

Wichmann of Norway, also supported by QuantiParts, built two-stroke engines: the AX family (300 × 450 mm, 1969 to 1985) and the type 28 (280 × 360 mm, 1986 to 1998). Designations such as 6AXA and 9AXAG decode under that maker.

Weichai / Yuchai / Zichai

Three Chinese makers use three unrelated systems, so the decoder treats them separately. Chinese-built MAN B&W and WinGD two-strokes carry the licensor’s designation; see CSSC marine engine subsidiaries.

Weichai builds the medium-speed 170 series (170 × 200 mm) and CW200 series (200 × 270 mm), where the digits after the cylinder count are the bore in millimeters, and the high-speed WP and WD engines, where the number is a size class. In the full model code the number after ZC or C is the rated power in metric horsepower (PS), and on WP and WD engines the number after the dash is the rated speed in hundreds of rpm. The Baudouin-Weichai article covers the Baudouin subsidiary.

Yuchai names marine engines by platform letters after YC6 (YC6K, YC6T, YC6C), not by bore; the number in the full code is the rated power in PS.

Zichai builds the 300 series, 300 × 380 mm, where the digits after the cylinder count are the bore in millimeters.

Worked examples

• X6170ZC818-5: Weichai 170 series, 6 cyl, 818 PS (601 kW).
• CW16V200ZC: Weichai CW200, 16 cyl vee, 200 × 270 mm.
• WP13C450-18: Weichai WP13, 450 PS at 1,800 rpm.
• YC6C960L-C23: Yuchai YC6C, 200 × 210 mm, 960 PS (706 kW).
• 6300ZLCA-4: Zichai 300 series, 6 cyl, 300 × 380 mm.

Scania Marine

Scania marine engines are the DI09 (in-line 5, 9.3 L), DI13 (in-line 6, 12.7 L) and DI16 (V8, 16.4 L). The data-plate code is DI plus the displacement in whole liters, a three-digit performance and certification code, and the application letter M. The DC codes are Scania’s industrial and generator engines with application letter A, not marine.

Worked examples

• DI13 072M: in-line 6, 130 × 160 mm, marine.
• DI16 076M: V8, 130 × 154 mm, marine.
• DI09 070M1: in-line 5, keel-cooled two-circuit version.

FPT / Iveco

FPT Industrial marine engines come from the NEF (N40, N45, N60, N67), Cursor (C90, C13, C16) and small S30 families. Commercial names are family plus rated horsepower (C13 825, N67 570 EVO); data sheets also give an engine code such as N40 ENT M25. Ratings run from A1 (high performance) to D (heavy duty).

Worked examples

• C13 825: Cursor 13, 135 × 150 mm, 825 hp.
• N67 570 EVO: NEF 6.7, 570 hp.
• C16 1000: Cursor 16, 141 × 170 mm, 1,000 hp.

John Deere PowerTech

John Deere PowerTech marine engines are 4.5, 6.8, 9.0 and 13.5 L in-line engines. The model code gives cylinders, displacement, air intake, user type, application and emissions code.

Grammar

<cylinders><displacement ×10, three digits><air intake><user type>M<emissions code>

6135SFM85 reads: 6 cylinders, 13.5 L, S turbocharged and aftercooled air-to-seawater, F OEM user type, M marine, 85 emissions-regulated. The air-intake letters are D naturally aspirated, T turbocharged, A aftercooled air-to-coolant and S aftercooled air-to-seawater. Duty classes M1 to M5 are printed with the rating, not in the model code.

Worked examples

• 6135SFM85: 6 cyl, 132 × 165 mm, 13.5 L.
• 6068SFM85: 6 cyl, 106 × 127 mm, 6.8 L.
• 4045TFM50: 4 cyl, 107 × 127 mm, turbocharged, non-emissions-regulated.

Perkins Marine

Perkins Sabre marine engines in Perkins Installation Manual TPD1317E are the four-cylinder M92, M92B and M115T and the six-cylinder M130C to M300Ti. The number is a nominal horsepower; the six-cylinder engines share a 100 × 127 mm, 6.0 L block.

Grammar

M<nominal hp>[B|C|T|Ti]: C commercial version, Ti turbocharged and intercooled pleasure version, T turbocharged, B the revised M92 with a 105 mm bore.

Worked examples

• M225Ti: 6 cyl, 100 × 127 mm, turbocharged intercooled.
• M130C: 6 cyl commercial version.
• M92B: 4 cyl, 105 × 127 mm.

Yanmar high-speed

Yanmar’s six-cylinder high-speed marine diesels include the 6LPA (4.2 L), 6LY (5.8 L) and 6LF (6.7 L). Model names give the cylinder count, series, revision and an installation or rating code (6LY3-ETP, 6LPA-STP2), or the crankshaft horsepower on common-rail models (6LY440, 6LF530). The decoder recognizes these designations but holds no ratings for them.

Worked examples

• 6LY3-ETP: 6 cyl LY series, revision 3.
• 6LF530: 6 cyl LF series, 530 mhp.
• 6LPA-STP2: 6 cyl LPA series.

Detroit Diesel

Detroit Diesel two-stroke marine engines (Series 53, 71, 92 and 149) are named <cylinders>-<series> in-line and <cylinders>V<series> vee, with N, T, TI and TA suffixes. Series 60 is a four-stroke in-line 6. The decoder holds the grammar and cylinder options for these engines, not ratings.

Grammar

<cylinders>-<series>[N|T|TI|TA] or <cylinders>V<series>[T|TI|TA]: T turbocharged, TI turbocharged and intercooled, TA turbocharged and aftercooled.

Worked examples

• 6-71N: in-line 6, Series 71.
• 8V92TA: V8, Series 92, turbocharged and aftercooled.
• 16V149TI: V16, Series 149, turbocharged and intercooled.

Baudouin

Baudouin (S.I. Baudouin, Cassis, part of the Weichai group) builds marine diesels from the 6W105M (136 kW) to the 12M55 (2,536 kW). W-series names carry the bore in millimeters; M- and F-series names carry the displacement per cylinder in deciliters, with .2 for mechanical and .3 for electronic engines.

Worked examples

• 6M26.3: 6 cyl, 150 × 150 mm, 2.6 L per cylinder, electronic.
• 12M33.2: V12, 150 × 185 mm, mechanical.
• 6W126M: 6 cyl, 126 mm bore, marine propulsion (S would be a generator set).
• 12M55: V12, 180 × 215 mm.

MAN Engines high-speed

MAN Engines (MAN Truck & Bus, Nuremberg, separate from Everllence) builds common-rail marine diesels on its 126 and 128 mm bore truck platforms: the in-line 6 D2676, the V8 D2868 and the V12 D2862. The code reads D diesel, two digits for the bore (28 = 128 mm), a stroke digit and a cylinder digit, then LE (turbocharged with intercooling, built-in engine) and a three-digit marine variant number.

Worked examples

• D2862 LE466: V12, 128 × 157 mm, up to 122.6 kW per cylinder at 2,300 rpm.
• D2676 LE453: in-line 6, 126 × 166 mm.
• D2868 LE436: V8, 128 × 157 mm.

Deutz and MWM

Legacy Deutz and MWM marine engines include the high-speed TBD 616 and TBD 620 and the medium-speed SBV 628 and 640. In SBV 8 M 628, S is marine, B turbocharged, V four-stroke and M water-cooled; the 6 is the generation and 28 the stroke in centimeters.

Worked examples

• SBV 6 M 628: 6 cyl, 240 × 280 mm.
• SBV 8 M 640: 8 cyl, 400 mm stroke.
• TBD 620 V16: V16, TBD 620 series.

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-marinized 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.

Makers outside the decoder database

The decoder covers the makers documented above. Engines from regional and historical makers are not in its database and return fuzzy suggestions rather than a decode. Their designations are covered, where the site has an article, in the maker’s own entry: Mirrlees Blackstone, Crossley Brothers, Ruston, Paxman, English Electric, Cooper-Bessemer, Atlas Polar, NOHAB Polar, Bolinder, Doxford opposed-piston, Kockums, Götaverken, Harland and Wolff, Krupp, Hesselman and Deutz.

License-built engines need no separate entry. HD Hyundai (Everllence B&W and WinGD engines), Hanwha Engine, Mitsui, CSSC’s yards and the other licensees build MAN B&W, WinGD and J-ENG two-strokes under the licensor’s designation, so a 6G70ME-C from any of them decodes under MAN B&W.

How the calculator interprets each segment

The marine engine model decoder calculator parses a string in eight steps:

1. Normalization: the input is uppercased, whitespace collapsed and the Roman numeral Ⅱ read as II.
2. Compact form: a copy with dashes and spaces removed (slashes and colons kept) feeds the parsers that ignore them. The WinGD and MAN four-stroke parsers read the dashed form, because X92-1.1 and X921.1 differ.
3. Per-maker parsers: fifteen grammar parsers are tried in order: Sulzer/Wärtsilä two-stroke, J-ENG UEC, WinGD, MAN B&W, MAN four-stroke, Wärtsilä four-stroke, HiMSEN, MaK, Daihatsu, Niigata, Yanmar, Bergen, MTU, Detroit Diesel and Weichai, then a lookup against every maker’s listed examples. Last comes a family match for makers without a grammar parser: a known model name with a cylinder count in front or up to five rating, gear or application letters after it (6AH41AK, K28BLFD, QSK50-M).
4. Brand and descriptive words: if nothing matches, a leading brand (HiMSEN, MAN B&W, Everllence B&W, Wärtsilä, Hanwha) and words such as “diesel engine” are removed and the parsers run again, preferring the maker the brand names. A licensee’s name prefers the licensor’s grammar.
5. Segment coloring: each captured piece becomes a colored segment: cylinders, stroke, bore, type, mark, fuel, configuration.
6. Family lookup: the parsed key (G70ME-C9.5, H32/40V, UEC50LSJ, M43C) indexes the database. Families whose figures couldn’t be traced to a maker document are held for decoding only, and the breakdown says so.
7. Generation: the family’s status gives current, legacy or flagship.
8. Fuzzy suggestions: for unmatched input, the four nearest listed designations by Levenshtein distance are offered.

Everything runs in the browser. The data is the single file shared/engines.json.

Why a forgiving parser matters

Operators, surveyors and superintendents type engine designations into spreadsheets, emails, work orders and inspection reports, and the typography rarely matches the maker’s:

• Capitalization varies (6s60mc-c).
• Dashes are inconsistent (6S60MCC, 6S60MC-C, 6S60 MC-C).
• Spaces appear anywhere (6 S 60 MC C); MaK and mtu print their own designations with spaces (12 VM 43 C, 16 V 4000 M73 L).
• Brand names come first (HiMSEN H21/32, HiMSEN Diesel Engine H21/32, MAN B&W 6S60MC-C).
• Cylinder counts are left out at platform level (UEC50LSE, K42EF).
• Mark numbers come with or without dashes (ME-C10.5, MEC10.5).

When the canonical form differs from the input, the calculator shows a “normalized to” line naming the engine it matched, so the user can see what was read. Unmatched input gets the four nearest designations as suggestions.

Identifying an engine in the field

Surveyors, port-state-control officers and superintendents frequently need to identify an engine from incomplete or partly-obscured nameplate data. A few rules of thumb derived from the structured naming conventions above:

• Two-stroke vs four-stroke at a glance: a stroke letter or series code followed by a bore in centimeters with no stroke (S60, X72, UEC50, RTA84) denotes a two-stroke crosshead engine. Two numbers separated by a slash or colon denote a four-stroke trunk-piston engine, and the numbers are bore and stroke in centimeters: MAN 48/60 is 480 × 600 mm, HiMSEN H21/32 is 210 × 320 mm, Bergen B33:45 is 330 × 450 mm. Stork-Werkspoor, Pielstick and the Chinese 170 and 300 series are the makers that write a bore in millimeters.
• MAN B&W vs WinGD vs Mitsubishi at a glance: B&W = S/L/K/G stroke prefix; WinGD = X prefix; Mitsubishi = UEC prefix. RT, RTA, RT-flex without an X are pre-2015 Sulzer/Wärtsilä legacy.
• MAN 4-stroke vs Wärtsilä 4-stroke: MAN uses bore/stroke notation with slash (9L48/60CR); Wärtsilä uses bore-only notation with the optional W prefix (9L46F, W46F).
• MaK vs Cat 3500 at a glance: MaK has M prefix and bore in centimeters (6M32C = 320 mm bore); Cat 3500/3600 has a 4-digit series number where the last two digits are cylinder count (3516C = 16 cyl).
• HiMSEN vs MAN 4-stroke: both write bore/stroke in centimeters with a slash. HiMSEN puts H before the bore and the vee letter after the stroke (16H32/40V); MAN puts L or V before the bore (12V32/44CR). HiMSEN C, DF, CDF and G models drop the stroke (7H21C, 9H35DF).
• Pre-MC B&W vs MC: pre-MC engines (1965-1982) use the EF, GF, GFC, GFCA, GB, GBE, BS suffixes; MC and later (1982 onwards) always start with M. A nameplate reading 9K45GFC is unambiguously pre-1982.

The decoder calculator applies these rules automatically and surfaces the maker name in the first row of every successful decode, so a user who has typed only 6UEC60LSII immediately sees “Mitsubishi UEC” attribution without needing to consult a reference card.

Database scope and updates

The database covers 40 makers and over 1,600 listed designations across two-stroke main engines, medium-speed and low-speed four-strokes, high-speed engines and gas turbines. In October 2026 every maker’s data was rechecked against its own documents: the Everllence Marine Engine Programme 2026, WinGD’s 2026 engine booklet, J-ENG’s 2026 UE catalog, HD Hyundai’s 2026 HiMSEN program, and the Wärtsilä, Caterpillar, Bergen, ABC, Daihatsu, IHI, Yanmar, Hanshin, Akasaka, Cummins, mtu, Volvo Penta, Scania, FPT, John Deere, Perkins, Baudouin and MAN Engines guides.

That check changed four kinds of data. Ratings moved to the current mark (the G95ME-C to 6,870 kW per cylinder, the Wärtsilä 32 to 580 kW per cylinder at 750 rpm, the MaK M46DF to 965 kW per cylinder). Designations that appear in no maker document were removed: the HiMSEN H22/26, H27/38 and H46DF, the WinGD X92-1.2, the UEC LSGI and LSC codes, the Daihatsu DK-32 and DK-46, the mtu Series 8000-M90. Letter meanings were corrected: UEC means Uniflow scavenging, Exhaust gas turbocharger, Crosshead; HiMSEN C means Clean; Daihatsu DC doesn’t mean vee; mtu L means power uprated. Families whose figures rest only on trade press or secondary lists were kept for decoding but show no rating.

A second pass in October 2026 added the historical engines still in the fleet and the newest releases. MAN B&W MC and MC-C ratings now come from MAN B&W’s own engine pages and the MAN 2010 program; Sulzer RTA and RT-flex versions from Wärtsilä’s catalogs and technology reviews; the J-ENG UEC LS, LA, LSII and LSE generations from engine lists published by the UE licensee Akasaka; the Caterpillar 3600 series from Cat’s 3600 Marine Application and Installation Guide (LEKM8461); Hanshin LU and EL from Hanshin’s Technical News; Detroit Diesel bore and stroke from Detroit Diesel operator manuals; Cummins, Volvo Penta, John Deere and some Yanmar figures from US EPA marine engine certification data; and other Yanmar, John Deere and FPT figures from maker data sheets published by their distributors. New engines in the same pass include the Everllence 175DF-M methanol engine, the J-ENG UEC35LSGH, the HiMSEN H35CDF, the Cat C32B and 3516E High Output, and the Niigata 28ADF ammonia engine. Pre-1982 Burmeister & Wain types, the Sulzer RD, RND, RLA and RLB, and the Bergen K-series still decode without ratings: their figures appear only in trade press or secondary lists.

A weekly check reads the makers’ own pages and documents for designations the database doesn’t hold: the Everllence Marine Engine Programme, product pages and market update notes, WinGD’s engine portfolio, J-ENG’s line-up and catalog, HD Hyundai’s HiMSEN pages and news, Caterpillar’s product catalog, and the product pages of Wärtsilä, Bergen, ABC, Akasaka, Hanshin, IHI, Weichai, Baudouin, mtu, Cummins, Volvo Penta, Scania and MAN Engines. A new designation opens a review task; it reaches the database only once a maker document gives its figures.

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
• BMEP calculator
• Brake Thermal Efficiency calculator
• BTE from SFOC calculator
• System - Emergency Genset: High-speed diesel

Additional related wiki articles:

• Marine diesel engine
• Two-Stroke Marine Diesel Engine Fundamentals
• Four-Stroke Marine Diesel Engine Fundamentals
• Marine Auxiliary Engines and Generators
• HiMSEN Medium-Speed Marine Engines (Hyundai)
• WinGD X-DF Dual-Fuel Architecture
• MAN B&W ME-C electronic control overview
• Methanol marine engines overview
• Ammonia marine engines overview
• 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
• Marine engine fuel injection systems
• Marine engine common-rail technology
• Marine engine turbocharging
• Engine load diagram and operating envelope
• Engine performance monitoring (PMI)
• Engine derating for slow steaming
• Slow steaming and engine cleanliness
• Two-stroke engine future developments
• Exhaust valve actuation in two-stroke engines
• Cylinder lubrication systems for two-stroke engines
• Cylinder liner design for two-stroke engines
• Piston ring pack design for two-stroke engines
• Piston crown cooling in slow-speed engines
• Uniflow scavenging in two-stroke marine engines
• Crosshead diesel engine architecture overview
• Trunk-piston engine architecture
• Medium-speed four-stroke marine engines
• High-speed four-stroke marine engines
• Marine engine combustion analysis
• Marine engine camshaft and valve train
• Marine engine crankshaft and main bearings
• Marine engine cylinder liners and pistons
• Engine bedplate construction
• Engine alignment and bedplate flexure
• Engine torsional vibration analysis
• Engine starting air system
• Engine governor systems
• Engine reversing system
• Engine telegraph and remote control
• Engine emergency stop circuits
• Engine sea trial procedures
• Engine room automation and monitoring
• Engine maintenance scheduling overview

Calculators that use engine designation as input

• EEDI Attained calculator: IMO Energy Efficiency Design Index, parameterized 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, parameterized 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 catalog.

Background reading on engine architecture and lineage

• MAN Energy Solutions corporate history
• WinGD corporate history
• Wärtsilä corporate history
• Sulzer marine diesel engines history
• Mitsubishi UEC two-stroke engines
• Caterpillar Marine corporate history
• Hanwha Engine corporate history
• HHI Engine Machinery Division
• Two-stroke engine future developments

Engineering specifications matrix

This section gathers the bore, stroke, stroke-to-bore ratio, cylinder-count permutations, rated power per cylinder (L1 / MCR), and total power-output range for the principal commercial marine engine programs in service. It is intended as the encyclopedic counterpart to the live decoder calculator: once the calculator has identified a maker and a model, this matrix supplies the dimensional and power context.

How to read the tables

• Bore is the cylinder diameter in millimeters. In a two-stroke name the bore is given in centimeters (a G95ME-C has a 950 mm bore, an X62 a 620 mm bore). Four-stroke names from MAN, HiMSEN and Bergen give bore and stroke in centimeters (MAN 35/44DF is 350 × 440 mm).
• Stroke is the piston-travel distance per stroke in millimeters. The stroke-to-bore ratio is the design lever that distinguishes K (short), L (long), S (super-long) and G (ultra-long “Green”) variants in the MAN B&W lineage, and that distinguishes legacy loop-scavenged Sulzer (RD / RND, ratios near 1.7) from modern uniflow-scavenged WinGD (ratios 3.7 to 4.5).
• Cylinder permutations lists the standard cylinder counts the maker offers in series production for that platform. Two-stroke engines are exclusively in-line; four-stroke engines use the configuration prefix L (in-line) or V (vee-bank).
• Power per cylinder (L1) is the manufacturer’s reference rating at the upper-left corner of the layout diagram (maximum continuous rating at maximum speed). Real-world ratings are usually de-rated to L2 / L3 / L4 to suit the propeller match and the operating profile of the vessel; consult the maker’s project guide for the layout-diagram envelope of any given Mark version.
• Total power output range spans the smallest-cylinder-count to the largest-cylinder-count variant at L1.

The dimensional and power profiles below apply to the current Mark version of each platform unless otherwise noted. Within a model line, alternative-fuel variants (MAN ME-GI / GA / LGIP / LGIM / LGIA; WinGD X-DF / DF-M / DF-A / DF-P / DF-HP) maintain the bore, stroke, cylinder count and L1 power of the baseline diesel platform; the differences are in the fuel-supply train, injector type, control strategy and emissions behavior, not the structural dimensions. Earlier Mark versions of the same model name carry slightly lower L1 per cylinder; the Everllence and WinGD project guides list the exact L1 / L2 / L3 / L4 layout points for every Mark.

MAN B&W / Everllence two-stroke specifications

The figures are each engine’s L1 rating: maximum continuous rating at the upper-left corner of the layout diagram. Rows labeled with a full mark (G95ME-C10.7) come from the Everllence Marine Engine Programme 2026 or, for engines no longer in it, from the most recent MAN program or project guide that lists them; “legacy” means the engine has left the current program. MAN B&W stroke letters encode the stroke-to-bore class: K short, L long, S super-long, G “Green” ultra-long.

Earlier marks of the same bore carry lower ratings: the G70ME-C9.5 is 3,640 kW per cylinder at 83 rpm against 3,770 at 86 rpm for the G70ME-C10.7. The decoder reports the rating for the exact mark typed, and the current-program rating when no mark is given. Legacy MC and MC-C rows carry the mark the source rated: the bare K98MC and K98MC-C rows are Mk 6 figures from MAN B&W’s own engine pages, and K98MC7 and K98MC-C7 come from the MAN 2010 program.

WinGD two-stroke specifications

From WinGD’s 2026 engine booklet and model pages, at the R1 rating point. Dual-fuel rows give the gas-mode rating.

Sulzer and Wärtsilä two-stroke specifications

From Wärtsilä technology reviews and press releases. The RD, RND, RLA and RLB families and several RTA types decode by grammar only, because no rating for them was traced to a Sulzer or Wärtsilä document.

J-ENG UEC two-stroke specifications

From the J-ENG UE catalog 2026 and J-ENG model pages.

Medium-speed four-stroke specifications

Medium-speed engines run at roughly 500 to 1,200 rpm, with stroke-to-bore ratios between 1.1 and 1.6. In-line versions (L) cover the smaller cylinder counts and vee versions (V) the larger. The tables give each family’s highest standard rating per cylinder; generator and propulsion ratings differ, and the engine’s own technical file governs.

MAN / Everllence four-stroke (Everllence Marine Engine Programme 2026 and the 2024 MAN program):

Wärtsilä (Wärtsilä product guides and product pages):

HD Hyundai HiMSEN (HiMSEN program 2026; legacy rows from HHI’s 2010 catalog):

MaK / Caterpillar (Cat Marine Power Solutions guide and Caterpillar Motoren documents):

Bergen (Bergen Engines data sheets):

Anglo Belgian Corporation (ABC product guide):

Pielstick (SEMT and Everllence documents):

Daihatsu Infinearth (Daihatsu catalog):

Niigata / IHI Power Systems (IHI engine selection guide):

Yanmar (Yanmar Europe product pages):

Caterpillar 3500 and 3600 (Cat 3600 Marine Application and Installation Guide LEKM8461, Cat marine spec sheets). Cat rates each engine by duty class, from A (unrestricted continuous) to E (high performance), and the kW per cylinder here is the class the spec sheet gives: the 3600 rows are maximum continuous ratings, the 3516E and 3516E High Output rows D (intermittent) ratings. On a C (maximum continuous) rating the 3516E is 2,525 kW, 157.8 kW per cylinder.

Caterpillar C-series (Cat marine spec sheets). Ratings are per Cat duty class: the C32B row is an E (high performance) rating and the C175-16 row a B (heavy duty) rating.

Low-speed four-stroke specifications

Hanshin and Akasaka build direct-drive or geared four-stroke main engines for Japanese coastal ships, running at 220 to 470 rpm with stroke-to-bore ratios near 2, closer to a two-stroke than to a medium-speed engine.

Hanshin (Hanshin product pages):

Akasaka (Akasaka catalog):

Cross-platform power-class summary

For quick orientation, the table below maps modern engine families to vessel-installed-power categories. Use this to scope the propulsion options for a given DWT or TEU capacity; specific selection requires the detailed bore-stroke-cylinder tables above plus the EEDI Attained calculator and SFOC sensitivity calculator to compare candidates on regulatory compliance and operating-cost terms.

For the per-character grammar that lets the decoder calculator extract maker, cylinder count, bore, stroke prefix, generation and fuel system from any input string, see the MAN B&W grammar table and the WinGD X-series grammar table above. For the fuel-injection-system context that distinguishes mechanical MC from electronic ME, see common-rail fuel injection on two-stroke engines and exhaust valve actuation in two-stroke engines. For the dual-fuel architecture that distinguishes high-pressure ME-GI / X-DF-HP from low-pressure ME-GA / X-DF, see Tier III compliant two-stroke engines and WinGD X-DF dual-fuel architecture.

Sources

• Everllence (formerly MAN Energy Solutions): Marine Engine Programme 2026, the source of the MAN B&W two-stroke and MAN four-stroke designation keys and ratings.
• WinGD: engine portfolio and the 2026 engine booklet, with the X-series designation legend.
• Japan Engine Corporation: UE engine line-up and the UE catalog 2026.
• HD Hyundai Heavy Industries Engine & Machinery: HiMSEN engine program 2026, designation key on page 11. HHI’s product pages for HiMSEN diesel engines and HiMSEN dual-fuel engines, and its pages for the Everllence B&W and WinGD two-strokes it builds under license.
• Wärtsilä: marine engines and generating sets and the product guides for the W20, W31, W32 and W46F.
• Caterpillar Marine: Cat Marine Power Solutions guide (MaK M-series) and Cat 3500 and C-series spec sheets.
• Bergen Engines: B33:45L propulsion data sheet and the other 2025 engine data sheets.
• IHI Power Systems (NIIGATA), Daihatsu Infinearth, Yanmar, Hanshin Diesel and Akasaka Diesels: product catalogs and selection guides.
• Rolls-Royce Solutions: mtu Marine and Offshore Solution Guide, with the designation key and application groups.
• Cummins, Volvo Penta, Scania, FPT Industrial, John Deere, Perkins, Baudouin and MAN Engines: marine product guides and spec sheets.
• IMO: MARPOL Annex VI Regulation 13 and the NOx Technical Code 2008, under which engines are certified by designation.

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