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The C12.9 marine propulsion engine is ideal for high performance marine applications including yachts, fishing vessels, military vessels, governmental vessels and various other commercial high performance marine applications. The C12.9 is designed to be integrated with both the Cat Three60 Precision Control shaft line maneuvering and engine control solution as well as other marine industry throttle controls. The electronically-controlled C12.9 is offered in two power ratings: 850 mhp at 2300 rpm and 1000 mhp at 2300 rpm. Both ratings meet EPA Tier 3, IMO II, EU Recreational Craft Directive and EU Stage IIIA regulations. In addition to high power density, the C12.9 offers high torque at low engine speeds and fast acceleration throughout the entire engine speed range due to its air system design of integrated series turbochargers and a supercharger.


  • Power Range 850-1000 mhp, 838-985 bhp, 625-735 bkW 850-1000 mhp, 838-985 bhp, 625-735 bkW


  • Speed Range 2300 rpm 2300 rpm
  • Emissions EPA Tier 3, IMO II, EU Stage IIIA EPA Tier 3, IMO II, EU Stage IIIA
  • Aspiration TA TA
  • Bore 5.31 in 135.0 mm
  • Stroke 5.9 in 150.0 mm
  • Displacement 787.0 in³ 12.9 l
  • Rotation from Flywheel End Counterclockwise Counterclockwise
  • Configuration In-line 6, 4-Stroke-Cycle Diesel In-line 6, 4-Stroke-Cycle Diesel

Dimensions & Weights

  • Height - Engine 42.7 in 1085.0 mm
  • Length - Engine 57.6 in 1463.0 mm
  • Width - Engine 43.7 in 1110.0 mm

Power Density

High power density

Electronic control system

Industry-leading torque and throttle response at low speed


Smooth, quiet operation throughout the entire operating range

Ventilation system

Closed crankcase ventilation system improves engine room cleanliness

Common rail fuel system

Common rail fuel system enables optimum combustion, low emissions and reduced noise

Engine Control Panel

Available on-engine control panel with “Start,” “Stop,” and display for engine diagnostics

Inlet Air Heater

Inlet air heater for improved cold weather startability


Low maintenance (fresh water/coolant) aftercoolers

Electrical Advantages

12V or 24V electrical system

Remote Monitoring

gplink ready for remote engine and vessel monitoring

C12.9 Optional Equipment


  • 24V 120 amp
  • 24V 160 amp
  • 12V 200 amp

Electric starting motor

  • 12V
  • 24V

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