Thoughts on Electric or Hybrid Drives

Thoughts on Electric vs Hybrid Drives

Open any yachting magazine, and you’ll see mention of electric and hybrid drives. More than a trend, these propulsion systems offer significant advantages. New technology is exciting, but it’s essential to understand what you’re stepping into before investing in a costly system.

What is a Hybrid Drive?

Hybrid drives in yachts follow the EV principle used in cars: combining a traditional internal combustion engine (ICE) with an electric motor. The torque and power of both systems are matched to create a performance profile that wouldn’t otherwise be possible.

Example application: a harbor tug operating at low power most of the time, then needing full power for short bursts. By integrating an electric trolling option and a battery bank, the diesel engine can run intermittently at moderate load to charge the batteries, then shut off until more power is required. Benefits include:

• Improved fuel efficiency

• Reduced engine wear

• Lower emissions

Series vs Parallel Hybrid Systems

• Series Hybrid: Diesel engines run generators to charge a battery bank, powering electric motors connected to the propellers.

• Parallel Hybrid: Diesel engines and electric motors can both drive the propellers directly.

For Vanguard, we selected a parallel hybrid system to maintain traditional diesel capability while gaining the advantages of hybrid operation, offering greater redundancy and easier resale in a conservative market.

Choosing the Right Manufacturer

We evaluated five suppliers: Marine Hybrid, Esco, Praxis, Transfluid, and TEMA. Key requirements:

• Compatibility with slow-running John Deere diesel engines

• Ability to power two propellers from one engine

• Large battery bank for silent, low-speed operations (~20 kW for trolling/maneuvering)

The hybrid motor sizing was dictated by the need to charge batteries rapidly, not to power the yacht at full speed.

Advantages of Our Hybrid Drive

1. Silent operation in sensitive areas or during dynamic positioning (DP) at night

2. Space savings by removing main and standby diesel generators

3. Dynamic positioning capability with instant torque and quick direction changes

4. Reduced engine hours, driving two props from a single engine when possible

5. High redundancy—flexibility to operate in multiple configurations

Future-Proofing

Our system is designed to expand as battery technology improves, particularly with advances in electric vehicle (EV) power density. This ensures Vanguard can adopt new tech without compromising traditional diesel propulsion.

Conclusion

Do we need a hybrid system? Perhaps not. Do we want to experiment and gain the flexibility it offers? Absolutely. For Vanguard, the hybrid drive enhances efficiency, reduces emissions, and adds fun tech play without affecting traditional propulsion reliability.

Fun fact: as a Star Trek fan, I now get to tell my son, “No. 1 – engage hybrids and take us out of here!”