Real‑World Insights from an Early Balance Catamaran Sea Trial
Introduction
Hybrid propulsion promises quieter operation, greater efficiency, and more flexibility underway — but the real question for most owners is simple: how does it actually perform on a real boat, in real conditions?
This article unpacks early sea‑trial data from an Integrel E‑Drive installation — known aboard Balance Catamarans as VersaDrive — using a Balance 482 as the test platform. Rather than focusing on lab simulations or theoretical curves, these results come from on‑water experiments conducted during commissioning, with the boat operated exactly as an owner would use it.
The goal here is not to overwhelm with raw numbers, nor to simplify the system into marketing slogans. Instead, we aim to explain what the data shows, why it behaves the way it does, and — most importantly — what it means for owners and prospective buyers considering hybrid propulsion.
While the experiments were conducted on a Balance 482, the insights translate broadly across the Balance range. Future trials across additional hulls and configurations will refine these findings further, but this first dataset already reveals some compelling and practical patterns.
Test Platform & Conditions
All experiments were conducted aboard a Balance 482 during early sea trials and commissioning, with the following consistent conditions:
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Sea state: Relatively flat, light chop
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Wind: Approximately 12–15 knots true, predominantly on the beam
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Course: Beam reach to minimise positive or negative sailing influence
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Load state: 12A Solar in and small draw from navigation instruments
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Engines: At Balance we use Yanmar 45 hp engines on our 482 (and 502) models.
Running the boat with the wind on the beam was deliberate. This ensured the results were not artificially enhanced by sailing assistance, nor unfairly penalised by headwinds. The intention was repeatability and neutrality — letting propulsion performance stand on its own.
One important procedural note: changes in RPM require approximately 30–40 seconds to stabilise. Early readings sometimes reflected transitional states rather than steady averages. For clarity, averaged values are used in interpretation, even where spoken call‑outs differ slightly.
How to Read the Data
Before diving into the experiments, it’s worth clarifying how the system reports power:
Charge / discharge values represent net battery flow
The Larger system number (centre top) includes background loads (electronics, solar input)
The Smaller, localised figures (under each icon) represent engine and motor specific behaviour
Throughout this article, emphasis is placed on trends and relationships rather than isolated peak numbers. Hybrid propulsion is about finding efficient operating zones — not chasing extremes.
The Experiments
Rather than following the chronological order of the video, the experiments are grouped here by operating mode. This makes the results easier to interpret and compare.
1. Pure Electric Propulsion
Twin Motors vs Single Motor
Running both electric motors in pure electric mode demonstrated smooth, silent propulsion — but also highlighted how quickly energy demand rises with speed.
At low RPM, twin electric motors delivered modest speeds with minimal discharge. As RPM increased, boat speed rose predictably, but discharge climbed steeply beyond mid‑range settings. At higher electric RPMs, the energy draw became substantial, limiting endurance to relatively short durations at higher speeds.
The chart below illustrates why pure electric propulsion is best suited to low-to-moderate speeds, with energy demand rising sharply beyond mid-range RPM.
Switching to a single electric motor revealed one of the most interesting early findings: comparable low‑speed performance with roughly half the discharge. For displacement speeds around 4–5 knots, a single motor provided a very usable balance between speed and efficiency.
This mode becomes especially compelling when paired with sail assistance. In light air, silent motorsailing allows meaningful boat speed without burning diesel or rapidly draining batteries — a use case that resonates strongly with owners prioritising quiet passages and low fuel consumption.
2. Diesel Propulsion with Charging
Single Diesel Charging
Engaging a single diesel engine with VersaDrive charging illustrated how available engine power can be harvested efficiently — but only within certain RPM bands.
At lower RPMs, adding electrical load actually improves engine efficiency by bringing the engine closer to its optimal operating range. Charging rates increased as RPM rose through the mid‑range, peaking before gradually tapering off at higher RPMs.
Beyond roughly 2,100 RPM, the propeller increasingly demands all available engine output, leaving less surplus power for generation. The system responds intelligently by backing off charge rather than compromising propulsion.
The takeaway: charging does not penalise boat speed — it simply adapts to available power.
The relationship between RPM, boat speed, and available charge is illustrated below.
3. Diesel Propulsion Without Charging (Baseline)
To establish a fair reference, identical RPM and speed runs were conducted with charging disabled.
These baseline passes confirmed an important principle: when charging is enabled, boat speed remains effectively unchanged. Side‑by‑side comparisons show nearly identical speed curves whether charging is active or not.
This validates a core design goal of VersaDrive — energy recovery without propulsion penalty.
4. Twin Diesels: With and Without Charging
Running both diesel engines together provided further confirmation of the system’s neutrality.
Across the RPM range, speed under twin diesels with charging closely mirrored speed without charging. Meanwhile, charging rates climbed significantly at moderate cruising speeds, particularly in the 6–7 knot range.
This region emerged as a recurring efficiency “sweet spot” — delivering solid passage speed while generating meaningful electrical energy (~13kW – wow).
Side-by-side comparisons show nearly identical speed curves whether charging is active or not.
5. Hybrid Propulsion: One Diesel + One Electric
Perhaps the most revealing mode was true hybrid operation, with one diesel engine and one electric motor both contributing to propulsion.
In this configuration, the boat achieved speeds above 6 knots while remaining at a neutral or slightly positive charge state. In other words, the system was propelling the boat forward while simultaneously replenishing the batteries.
This operating mode dramatically extends range per litre of fuel. When dialled in correctly, hybrid propulsion has been calculated to deliver 35–40% improved fuel efficiency compared to conventional motoring.
For passagemaking — particularly in light winds or motor‑sailing scenarios — this mode unlocks flexibility that traditional propulsion simply cannot match.
6. At‑Anchor Charging
While much attention naturally focuses on underway performance, one of the most compelling advantages of VersaDrive emerges at anchor.
With engines in neutral, the system demonstrated the ability to generate substantial electrical power:
Low RPM idle produced modest, continuous charge
Mid‑range RPM delivered double‑digit kilowatt output
Twin engines increased capacity further, reaching 20+ kW in optimal conditions
This capability transforms life aboard. High‑load systems — watermakers, air‑conditioning, cooking appliances — can be run efficiently while dramatically reducing noise, fuel consumption and total engine hours.
For many owners, this at‑anchor performance alone justifies the move to a hybrid system.
Key Takeaways
Across all experiments, several clear themes emerged:
Single‑motor electric propulsion offers excellent low‑speed efficiency
Charging never compromises propulsion performance
Mid‑range RPMs deliver the best charge‑to‑speed ratios
Hybrid propulsion meaningfully extends range and efficiency
At‑anchor charging dramatically improves onboard quality of life
VersaDrive doesn’t force a single “correct” way to operate the boat. Instead, it gives owners options — allowing propulsion strategy to adapt to conditions, priorities, and personal cruising style.
What This Means for Owners
For Balance owners, VersaDrive aligns closely with the brand’s ethos: engineered for performance, crafted for quality, designed for living.
Whether it’s silent motorsailing, efficient passage speeds, reduced fuel burn, or quieter nights at anchor, the system enhances both the experience of sailing and the practicality of life aboard.
These early results represent just the beginning. As more boats log miles across different hulls and conditions, the dataset will continue to grow — refining best practices and revealing new optimisation strategies.
For now, the message is clear: hybrid propulsion, when executed properly, delivers real‑world benefits that go far beyond theory.
Further data, charts, and ongoing updates will continue to be added as additional trials are completed across the Balance fleet.
