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Independent engine comparison
Cummins Marine Engine vs MAN Marine Engine
Performance motor yachts, sportfishing boats and high-output shaft drives. This guide compares real selection and ownership factors for Australian boats rather than declaring a winner from headline horsepower.
Where this marine engine comparison is valid
Comparing yacht-rated engines for the same displacement, performance target, shaft system and annual use.
Cummins and MAN can overlap in performance-vessel conversations, especially where conventional shafts are retained. The specific models, however, may differ greatly in displacement, rated speed, output density and service envelope.
Cummins publishes distinct marine ratings across engine families. MAN’s yacht range is aimed at high-output leisure and sportfishing applications. Require written application approval and performance prediction from both sides.
Representative model matchup
Cummins QSM11 715 vs MAN D2676 LE446 730 Marine Engine
A light-duty or performance-commercial comparison in the low-700 hp class. Exact application rules still need to be aligned even though output and installed scale appear close.
On a phone, swipe across the table to compare both model specifications.
| Published specification | Cummins QSM11 715 | MAN D2676 LE446 |
|---|---|---|
| Rated output | 526 kW / 715 mhp | 537 kW / 730 hp |
| Rated speed | 2,500 rpm | 2,300 rpm |
| Cylinder layout | 6 in-line | 6 in-line |
| Displacement | 10.8 L | 12.42 L |
| Published dry weight | 1,188 kg published product weight | About 1,215 kg dry |
| Rating or duty context | High Output | Light duty |
| Driveline context | Conventional marine gear and shaft | Conventional marine gear and shaft |
What the numbers mean: The MAN publishes 15 hp more at 200 rpm less and uses greater displacement. Compare permitted annual hours/full-load share, gear ratio, torque curve and emissions configuration—not peak power alone.
Specification boundary: Manufacturer data can change by market, emissions build, gear, cooling system and option package. Values above are a shortlisting snapshot, not installation approval. Obtain the current Australian datasheet and dimensioned drawing identified by model and specification revision.
Key marine engine differences
On a phone, swipe across the table to compare both marine engine options.
| Decision factor | Cummins Marine | MAN Marine |
|---|---|---|
| Rating | Confirm model, output, rpm, High Output or other applicable yacht rating. | Confirm exact yacht model, output, rpm and manufacturer application limits. |
| Machinery space | Check complete width, height, service side, exhaust and air demand. | Check V-engine service access, turbo and aftercooler space, exhaust and ventilation. |
| Driveline | Match gear input rating, ratio, shaft torque and propeller curve. | Match gearbox, shaft, propeller and hull performance prediction. |
| Lifecycle | Price cooling, aftercooler, injector and turbo work with access labour. | Price scheduled major service, access requirements and specialist support. |
For both candidates, also compare exact yacht rating and permitted operating profile; installed dimensions, weight and ventilation demand; gearbox, shaft torque and propeller calculation; major-service access and regional technician capability. Never treat a higher intermittent or recreational output as equivalent to a lower continuous or commercial rating without reading the manufacturer’s rating definition.
Maintenance and ownership in Australia
On a performance yacht, low annual hours do not eliminate calendar maintenance or the cost of inaccessible components. Include lifting points, deck openings and furniture removal in the service plan before accepting the installation.
Ask who will commission the installation, who can access model-specific diagnostics, where routine parts are physically stocked and what the plan is if the boat operates outside a capital city. “Available in Australia” is not the same as a part being available near the vessel when it is immobilised.
Keep the engine model, serial number, gearbox or drive identity, control generation and specification sheet together in the vessel record. This prevents future parts orders from being based on appearance or a boat builder’s brochure.
Comparing used marine engines
A used engine is a condition-and-installation purchase, not a brand vote. Hours without load history, calendar age, cooling maintenance and oil evidence say little. Inspect the cold engine and retain photographs and readings from the trial.
- Download engine, control and drive event histories and verify displayed hours
- Review aftercooler, heat-exchanger, injector, turbo and major-service evidence
- Inspect conventional gear and shaft alignment or pod-drive underwater service history
- Confirm control, display, software and diagnostic generations remain supported
For a high-value purchase, arrange an independent inspection and consider oil analysis, cooling-system pressure testing and electronic history where supported. Read the pre-purchase engine checklistand sea-trial evidence guide.
Marine engine quote checklist
Give both suppliers the same vessel data and require these items in writing:
- Complete engine, driveline, controls and display architecture
- Installed weight, ventilation, exhaust, service access and removal plan
- Performance prediction, propeller or drive selection and acceptance criteria
- Commissioning data, sea trial, crew handover and regional support agreement
- Removal, installation, freight, haul-out, fluids, exclusions and tax
- Commissioning values, sea-trial acceptance criteria and warranty party
Compare the installed total, not an engine crate against a complete package. Use the repower measurement guideand comparable engine quote guide.
Which marine engine should you choose?
Decision rule: Use a naval-architect or propulsion-engineer comparison based on loaded performance and full installation scope, not a cost-per-horsepower shortcut.
Score the two exact proposals against non-negotiables first: correct duty, physical fit, driveline compatibility, safe service access and credible commissioning. Only then compare price, noise, controls and preferences. If either supplier cannot document the rating or installation, the proposal is not ready to compare.
Frequently asked questions
Which is better: Cummins Marine or MAN Marine?
Neither brand wins every installation. Compare exact models with equivalent duty ratings, then choose the complete package that fits the vessel, driveline, operating profile and available Australian support.
Can I replace Cummins Marine with MAN Marine?
Potentially, but it is not a like-for-like swap until mounts, shaft height, gearbox or drive, controls, exhaust, cooling, electrical system, service clearance, propeller match and removal path have been checked.
What should an engine comparison quote include?
It should name the exact engine model, output, rpm and duty rating plus the gearbox or drive, controls, mounts, cooling and exhaust changes, installation labour, propeller work, commissioning, sea trial, warranty party and exclusions.
Are the model families in this guide all sold new in Australia?
Not necessarily. Australian boats contain current and legacy engines. Confirm current supply, specification, certification, warranty and dealer support with the manufacturer or authorised Australian distributor.
Are Cummins QSM11 715 and MAN D2676 LE446 direct replacements?
No model should be treated as a direct replacement from a specification table alone. Verify duty approval, dimensions, mounts, shaft height, gearbox or drive, propeller match, cooling, exhaust, controls, electrical system, service clearances and the complete installed mass.
More marine engine comparisons
Practical summary
Make the comparison decision-ready
Compare like with like
Align duty rating, output, driveline, emissions basis and included equipment.
Verify fit
Check dimensions, mounts, shaft height, cooling, exhaust, ventilation and service access.
Price installed
Include controls, gearbox or drive, propeller work, labour, commissioning and haul-out.
Choose support
Name the Australian warranty party, commissioning technician and parts route before ordering.
- 1Engine envelope
- 2Mount centres
- 3Shaft height
- 4Service zones
- 5Removal path