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Craftsman Marine CM4.42 Keel Cooling
The Craftsman Marine Mitsubishi based diesel engines can also be fitted with keel cooling. This can be very beneficial for sailing through shallow or muddy waters or for shallow draft boats sailing through waters with limited depth. Due to unparalleled quality and superior service backed by decades of experience, these keel cooling engines are the perfect solution for smooth sailing through waters where mud, sand or debris can potentially damage and clog up a conventional water cooled system.
Our keel cooled engines are engineered using the latest cooling technology. Simply put, there is no need for a raw water pump, so eliminates one more service point from your engine. These engines reduce maintenance costs and minimise downtime. Using keel cooling, only the cooling liquid will be pumped through the engine and the keel cooler element by the engine water pump. As a consequence, a keel cooling engine requires a heat resistant exhaust system.
| Basic Engine | Mitsubishi |
|---|---|
| Cylinders | 4 In Line |
| Cylinder Capacity | 1.758 cm³ |
| Power | 30,9 kW / 42 hp |
| Max. Engine Speed | 3.000 rpm |
| Max. Torque | 105 Nm |
| Aspiration | Natural |
| Alternator | 90 A / 12 V (Bosch / SEG) |
| Cooling System | Keel Cooling |
| Flexible Engine Mounts | CM Type 5 |
| Calorifier Connection | Optional |
| Exhaust Diameter | BSP G11/2 thread |
| Electronic Protection | 10 A Circuit Breaker |
| Stop Solenoid | Energized To Stop |
| Max. Installation Angle | 15° (Backwards) |
| Weight | 175 kg |
| CM4.33, CM4.42, CM4.52 Manual 30072019_web |  |
|---|---|
| CM4_spareparts_catalogue | |
| CM433_CM442_manual_web_DE | |
| CM433_CM442_manual_web_DK | |
| CM433_CM442_manual_web_EN | |
| CM433_CM442_manual_web_FI | |
| CM433_CM442_manual_web_NL | |
| CM433_CM442_manual_web_NO | |
| CM442_Engine_with_ZF25_GearBox | |
| CM442_Engine_without_GearBox |  |
| CM442_performance | |
Applications & Compatibility
Keel cooling on the CM4.42 fits mid-sized builds operating where a raw water intake is a liability:
- Motor cruisers and trawlers running shallow, muddy, or debris-prone waters
- Workboats needing CM4.42-class torque without a raw water cooling circuit
- Compatible with the ZF25 gearbox for straightforward drivetrain integration
- Repower projects stepping up from a keel-cooled 2- or 3-cylinder Craftsman Marine engine
Built for Boat Builders & Dealers
As with the standard CM4.42, Craftsman Marine backs the Keel Cooling version with a shared Mitsubishi parts base, manuals in six languages, and a specification that stays the same from unit to unit, useful for a distributor stocking both cooling variants of the same engine. Bulk orders and OEM runs follow the same process either way, and the same distributor network supports both after the sale.
Technical Advantages
Moving the CM4.42 to keel cooling changes a specific set of maintenance points; here’s what that actually removes or alters:
- No raw water pump needed, removing one service point from the cooling circuit
- Only cooling liquid circulates through the engine and keel cooler element
- Heat-resistant exhaust system with BSP G1 1/2 thread connection, matched to keel cooling
- 10 A circuit breaker for straightforward electrical protection
Why Choose the CM4.42 Keel Cooling System
The CM4.42 Keel Cooling gives builders the same mid-range torque as the standard CM4.42, designed for boats that need to avoid a raw water intake; the sales case is about water conditions, not a different engine.
- Mitsubishi-based industrial engine platform, proven and supported worldwide
- Keel cooling removes the raw water pump as a maintenance point in silty or shallow waters
- Heat-resistant exhaust system matched to the keel cooling configuration
- Complies with RCD II regulations for recreational craft
- 175 kg build with CM Type 5 flexible engine mounts for straightforward installation
Frequently Asked Questions
Output stays at 30.9 kW (42 hp) from the same 1.758 cm³ Mitsubishi block; the cooling method (Keel Cooling) and the exhaust connection (BSP G1 1/2 thread, larger than the smaller engines’ keel-cooled variants) are what differ.
Yes, it’s a common choice where a raw water intake is a liability, shallow, silty or debris-prone commercial waters, while still delivering the same 105 Nm of torque as the standard CM4.42.
It removes the raw water pump as a service point entirely; everything else, the electric fuel lift pump, cupronickel components and 10 A circuit breaker, stays the same as the standard model.
The ZF25 gearbox, the same pairing documented for the standard CM4.42, listed in the Downloads section on this page.
Yes, CM Type 5 flexible engine mounts at 175 kg, with the same 15° maximum backward installation angle.
It shares the CM4 spare parts catalogue and CM4.33/CM4.42/CM4.52 manual with the standard CM4.42, listed in the Downloads section on this page.