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The Cat® C18 ACERT commercial marine propulsion engine has a high performance rating of 885 mhp (918 bhp) at 2200 rpm. It packs more of what you need without adding size and weight. So you can take more offshore without taking more on-board. Along with proven Caterpillar reliability and durability, the C18 ACERT marine propulsion engine offers expanded power capabilities with virtually smoke-free operation, maintaining a smaller impact on the environment. Exclusive ACERT Technology optimizes fuel economy, performance, and emission control with the C18 ACERT meeting Commercial Marine EPA Tier 2, CCNR Stage II, EU Stage IIIA Inland waterway, IMO by GL and ABS.


Intermittent Ratings - Maximum Power 873.0 bhp 651.0 bkW Less
High Performance Ratings - Maximum Power 1136.0 bhp 847.0 bkW Less


Configuration In-line 6, 4-Stroke-Cycle Diesel In-line 6, 4-Stroke-Cycle Diesel Less
Aspiration TA, TTA TA, TTA Less
Rotation (from flywheel end) Counterclockwise Counterclockwise Less
Stroke 7.2 in 183.0 mm Less
Bore 5.7 in 145.0 mm Less
Displacement 1106.0 in3 18.1 L Less

Dimensions & Weights

Minimum Dry Weight 3700.0 lb 1678.0 kg Less
Maximum Dry Weight 4200.0 lb 1905.0 kg Less
Minimum Length 59.2 in 1505.0 mm Less
Maximum Height 46.5 in 1182.0 mm Less
Minimum Width 42.1 in 1068.0 mm Less
Maximum Width 44.0 in 1118.0 mm Less
Minimum Height 45.0 in 1144.0 mm Less
Maximum Length 62.6 in 1591.0 mm Less


With phenomenal acceleration and outstanding performance the C18 proves to be a top competitor in the 1000 brake horsepower class.

Power & Acceleration

The new C18 propulsion engine has 25% more power, faster acceleration than the 3406E, and has an excellent power-to-weight ratio of 1.56 kg per metric horsepower or 3.49 lbs per brake horsepower. Even though the C18 has a slightly larger package it weighs approximately the same as the 3406E.

Electronic Control System

The ADEM III electronic control system provides engine speed governing, automatic air/fuel ratio control, engine parameter monitoring, and system diagnostics, as well as cold start strategy, engine synchronization, trolling mode strategy, and slow vessel mode. The C18 has a 70-pin customer connector compatible with the optional display systems – Marine Power Display, Marine Analog Power Display, and Engine Vision. C18 is also compatible with the Multi- Station Control System when available.

Excellent Power-to-Weight Ratio

With a 25% increase in power at approximately the same weight of the 3406E, the C18 engine has an outstanding power-to-weight ratio of 1.56 kg per metric horsepower or 3.49 lbs per brake horsepower.

Larger Bore, Stroke, and Displacement

The larger bore and stroke give the C18 24% greater displacement from a slightly larger package size than the 3406E.

Higher Capacity Fuel Injectors

Higher flow fuel injectors provide more fuel for combustion and in turn produce more power.

Faster Response

The two smaller turbochargers require less inertia to engage and thus provide more boost at lower engine speeds.

Outstanding Acceleration and Performance

This additional power provides quicker acceleration and allows the vessel to come up on plane faster.

Seawater Aftercooling and Integral Heat Exchanger System

The C18 engine has seawater aftercooling (SWAC) which also contributes to greater power output. The titanium plate heat exchanger incorporates the expansion tank, deaerators, thermostats, shunt line and crossover pipe providing a compact design.

Extremely Low Emissions

The design of the camshaft helps the engine develop higher injection pressures for lower smoke levels. The closed crankcase ventilation system removes oil vapor from the engine room.

Top Quality Appearance

High quality white urethane paint is standard with an optional superior quality

C18 ACERT Tier 2 Standard Equipment

Air Inlet System
  • Corrosion-resistant sea water aftercooled, air cleaner/fumes disposal (closed system), jacket water cooled turbocharger, turbocharger inlet OD straight connection

Exhaust System
  • Manifold & Turbocharger, water cooled

Fuel System
  • Fuel priming pump, fuel transfer pump, fuel filter - RH or LH service, flexible fuel lines

  • Electronic service meter, instrument panel (24V), start/stop switch, emergency stop button, maintenance due light, diagnostic light, warning light, maintenance clear switch, start motor magnetic switch, 15 and 3A breakers

Lube System
  • Crankcase breather; oil cooler; spin-on oil filter, RH service on port, LH service on starboard; center sump deep oil pan; oil filler; dipstick, RH service on port, LH service on starboard; gear-driven oil pump

Mounting System
  • Front support - adjustable

Power Takeoffs
  • Hydraulic pump drive, SAE A, 11 tooth spline
  • Crankshaft pulley

Protection System
  • A4 ECU Electronic Monitoring System provides customer programmable engine de-rate strategies to protect against adverse operating conditions

  • Vibration damper
  • Lifting eyes
  • Variable engine wiring

ISO Certification
  • Factory-designed systems built at Caterpillar
    ISO 9001:2000 certified facilities

Flywheel and Flywheel Housing
  • SAE No.0 Flywheel(136 Teeth) SAE No.0 Flywheel Housing

Control System
  • Electronic governing
  • Cold mode start strategy (3 cyl cutout)
  • Programmable low idle
  • Electronic diagnostics and fault logging
  • Engine and transmission monitoring(speed,temperature,pressure)
  • Fuel/air ratio control

Cooling System
  • Thermostat and housing
  • Jacket water pump, gear driven
  • Sea water pump, bronze impeller, self-priming, gear driven
  • Sea water pump, rubber impeller, self-priming, gear driven (D Rating)
  • Keel cooling- seperate circuit (keel cooled models only)
  • Heat exchanger, titanium plate with expansion tank (heat exchanger models only)

  • 2007 EPA Marine Tier 2 Commercial Emissions standards.
  • IMO (Annex VI)
  • EU Stage IIIa Inland Waterway (directive 97/68/EC)
  • CCNR Stage II

C18 ACERT Tier 2 Optional Equipment

Air Inlet System
  • Air Cleaner – Regular duty
  • Aftercooler Condensate drain

Charging System
  • Battery Charger, 10A
  • Charging Alternator, 24V 60A
  • Ammeter Gauge—24V

Cooling System
  • Rubber Impeller Sea Water Pump w/ 110 deg inlet (D Rating)

Exhaust System
  • Dry Elbow
  • Dual Dry Elbow (D Rating)
  • Watercooled Elbow
  • Flexible Fittings
  • Outlet Flange

Flywheels & Flywheel Housing
  • SAE #0 – RH and LH Service

Fuel System
  • Primary fuel filter
  • Primary Fuel/Water Separator
  • Duplex Fuel Filters
  • Fuel Cooler (Hex)
  • Fuel Cooler (Keel, shipped loose)

  • Variable Engine Wiring
  • Tachometer, Digital
  • Tachometer Mounting
  • Marine Power Display

Lube System
  • Manual Sump Pump – RH & LH
  • Transmission Oil Cooler
  • Duplex Oil Filters

Mounting System
  • Heavy Duty Front Support
  • Vibration Isolators

Power Take-Offs
  • Pulley and Damper, Crankshaft
  • Damper and Stub Shaft
  • Front Enclosed Clutch
  • Hydraulic Pump Drive Adapter

Starting System
  • Electric Starting Motor 24V – RH & LH
  • Air Starting Motor – LH
  • Jacket Water Heater, 120V or 240V
  • Battery Set — 24V, Dry
  • Air Pressure Regulator
  • Air Start Silencer

  • Bilge Pump Drive
  • Custom Paint
  • Damper Guard
  • Filter Cover Kit
  • Wiring Harness Removal 

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Extended Warranty and Support

Caterpillar offers a variety of integrated solutions to help you protect your investment, minimize owning and operating costs, and maximize up-time.

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