Hybrid Workboat Electrification
A concept study converting a diesel workboat to a battery-diesel hybrid. The question was not “can it be electrified” — almost anything can — but whether the vessel’s real duty cycle made a hybrid drivetrain worth the weight, cost and complexity. The engineering answers that with numbers, not optimism.
Does the Duty Cycle
Justify a Hybrid?
The operator was considering a hybrid conversion driven by fuel cost and emissions pressure, but had no quantified picture of whether their vessel’s actual operating profile suited it. A workboat that spends its day at steady transit power is a poor hybrid candidate; one with long idle and manoeuvring periods is a strong one.
Isca’s first job was to characterise the duty cycle honestly — how the vessel actually spends its operating hours — and only then size a battery and hybrid architecture against it.
Modelling the vessel’s typical day showed approximately [ x % ] of operating time at low load, the band where a battery displaces diesel most effectively. That figure is what makes or breaks the business case.
Sized to the Load.
Battery sizing is a balance: too small and the hybrid rarely helps; too large and you carry dead weight and cost. These figures define where that balance landed for this vessel — each to be confirmed by the worked energy model.
- Daily energy demand
- [ x kWh ]
- Usable battery capacity
- [ x kWh ]
- Peak electrical load
- [ x kW ]
- Genset rating retained
- [ x kW ]
- Added system mass
- [ x kg ]
- Indicative fuel reduction
- [ x % ]
What the Study Produced.
Duty Cycle Analysis
A characterisation of how the vessel actually operates, broken down by load band across a representative day.
Energy Demand Model
A model of daily and peak energy demand, used as the basis for all sizing decisions.
Battery Sizing Report
Recommended battery capacity with the reasoning, including the trade-off against mass and cost.
Hybrid Architecture
A single-line concept for the battery-diesel architecture, including the role of the retained generator.
Charging Strategy
How and when the battery is recharged against the vessel’s operating pattern and any shore connection.
Concept GA Impact
The arrangement implications of fitting the battery system — space, mass and stability flags for the next stage.
Profile to Concept.
Characterise the Duty
Establish how the vessel really operates before sizing anything to it.
Energy Demand
Build the daily and peak energy picture that every sizing decision rests on.
Battery & Architecture
Size the battery and define the hybrid architecture against the modelled load.
Arrangement Impact
Check the concept against space, mass and stability so the next stage starts informed.
The Engineering
Reasoning Behind It.
Marine + Electrical in One Team
Hybrid conversion sits exactly where naval architecture meets power systems. Isca does both, so the battery sizing and the stability impact are considered together, not in separate silos.
We Lead With the Duty Cycle
The honest first question is whether a hybrid suits the vessel at all. Starting there protects the client from a conversion that looks green on paper and underperforms in service.
Weight Is Engineering, Not an Afterthought
Batteries are heavy. We carry the added mass through to its stability and arrangement consequences in the same study, not as a surprise later.
A Concept That Can Be Built On
The output is structured so the next stage — detailed design — starts from sound numbers rather than re-opening the feasibility question.
Adjacent Studies.
Considering a Hybrid?
Before committing to a conversion, the question worth answering is whether your vessel’s duty cycle justifies it. That is where we start.
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