The propulsion architecture of Azzam exists because a single propulsion technology cannot efficiently satisfy all operational requirements of a 180-meter ultra-high-speed yacht.

The engineering problem was:

Build one of the world’s largest yachts while still achieving military-like speed characteristics.

That creates conflicting requirements:

RequirementEngineering ConflictHigh top speedRequires enormous peak powerLong cruising rangeRequires fuel efficiencyLow vibration/noiseConflicts with turbine operationReliabilityRequires redundancyManeuverabilityDifficult at 180m scaleShallow-water operationLimits conventional propeller design

The solution was a hybrid propulsion architecture.

Core Propulsion Architecture

Azzam reportedly uses:

• 2 × MTU diesel engines

• 2 × GE LM2500 gas turbines

• Advanced waterjet propulsion system

This is essentially a CODAG/WARP-style naval propulsion philosophy adapted for civilian superyacht use.

(CODAG = Combined Diesel And Gas)

Why Diesel Engines Are Needed

The diesel engines handle:

• economical cruising

• long-distance range

• lower-speed operation

• fuel-efficient transit

• hotel electrical stability

• redundancy

Diesel Advantages

1. Fuel Efficiency

Diesel engines are dramatically more efficient during:

• low-speed cruising

• long-range passages

• steady-state operation

Gas turbines are extremely inefficient at partial load.

Without diesels, operating costs would become irrational even at billionaire scale.

2. Reliability

Marine diesels:

• can run continuously for long durations

• have proven maritime reliability

• are easier to maintain globally

• tolerate variable operating conditions

For ocean-crossing capability, diesel propulsion remains essential.

3. Lower Acoustic Signature

Luxury yachts require:

• low vibration

• reduced cabin noise

• smooth cruising behavior

Diesels operating at optimized RPM are quieter and more stable for passenger comfort than turbines at continuous high output.

Why Gas Turbines Are Needed

The GE LM2500 turbines exist for one reason:

Peak Power Density

Azzam’s speed target (>30 knots) is extremely difficult at 180 meters.

A conventional diesel-only architecture would require:

• much larger machinery spaces

• enormous engine mass

• excessive shaft loading

• lower acceleration performance

Gas turbines solve this.

Turbine Advantages

1. Massive Power in Small Volume

Gas turbines generate extremely high horsepower relative to their size and weight.

This allows:

• higher top speed

• better acceleration

• lower machinery footprint

• improved hull packaging

The LM2500 is derived from aerospace technology and widely used in naval vessels.

2. Sprint Capability

Turbines are ideal for:

• temporary high-speed operation

• rapid acceleration

• maximum-output phases

They are effectively “boost engines.”

Azzam does not need turbines running continuously during standard cruising.

3. Weight Reduction

At this scale:

• every ton matters

• machinery weight affects stability

• hull dynamics become critical

Gas turbines produce superior power-to-weight ratios versus marine diesels.

Why Waterjets Instead of Conventional Propellers

This is one of the most important engineering decisions.

Conventional Propeller Limitation

At very high speeds:

• cavitation increases

• vibration rises

• efficiency drops

• propeller diameter becomes problematic

For a yacht targeting >30 knots at 180m, large conventional propellers become increasingly inefficient.

Waterjet Advantages

1. High-Speed Efficiency

Waterjets become advantageous at:

• high-speed planing regimes

• extreme propulsion loads

• fast maneuvering

They reduce cavitation effects at speed.

2. Shallow Draft Capability

Azzam reportedly required operation in relatively shallow Gulf waters.

Waterjets allow:

• reduced underwater appendages

• lower draft sensitivity

• safer shallow-water operation

3. Reduced Vibration

Critical for luxury applications.

Waterjets produce:

• smoother ride characteristics

• lower transmitted vibration

• quieter passenger experience

4. Maneuverability

Waterjets allow:

• vector thrust control

• tighter maneuvering

• improved port handling

Important for a vessel of this scale.

Why This System Is Technically Unusual

Most superyachts optimize for:

• comfort

• interior volume

• efficiency

Azzam optimized simultaneously for:

• extreme speed

• massive scale

• luxury comfort

• shallow-water capability

• low vibration

• transoceanic range

That combination is extraordinarily difficult.

The propulsion architecture resembles:

• naval engineering

• military fast-response ships

• advanced maritime defense platforms

more than traditional yacht engineering.

Estimated Operational Characteristics

ParameterEstimateTotal power~94,000 HPTop speed30–34 knotsFuel burn at max speedup to ~13 tons/hourPrimary cruise modedieselSprint modediesel + turbinesPropulsion typewaterjets

Engineering Conclusion

Azzam’s propulsion system is essentially a compromise optimizer between:

• speed

• luxury

• range

• acoustic comfort

• hull efficiency

• shallow-water operation

• machinery footprint

No single engine technology could achieve all of those goals simultaneously.

That is why the yacht uses:

• diesel engines for efficiency and endurance

• gas turbines for extreme peak power

• waterjets for high-speed hydrodynamic performance

The result remains one of the most sophisticated civilian marine propulsion systems ever built.