40 ft sailboat
Repower sizing guide

40-foot sailboat electric repower

Bigger cruisers and offshore boats — where 96 V starts to make real sense.

Start sizing this boatPre-filled with realistic defaults
Fits boats like
Beneteau Oceanis 40Jeanneau Sun Odyssey 410Hallberg-Rassy 40Hanse 418Bavaria Cruiser 41Dufour 412Hylas 42Amel 41

Not an exact match? The wizard adjusts to your real numbers — these are reference hulls for the typical sizing.

20–30 kW
Continuous power
30–45 kWh
Battery pack
210–310 A @ 96 V
DC current
30–55 nm
Cruise range
What this replaces — vs a 50 hp diesel
At 50 h motored per season (typical cruiser). Slider on the full summary lets you adjust.
Diesel displaced
284 L
per season
CO₂ avoided
762 kg
per season
Quieter
−23 dB
52 vs 75 dB(A)

What this segment looks like

Why a 40 ft sailboat is a sensible repower target

At 40 feet and 9–11 tonnes, a sailboat needs 20–30 kW continuous to maintain 6 kn and meaningful headroom against wind and current. This is where 96 V bus voltage stops being optional — DC currents at 48 V become awkward to cable.

  • 96 V halves your DC current vs 48 V — cable cross-section drops to manageable levels.
  • 30+ kWh is the realistic minimum for offshore work with reserves.
  • Shaft drive is still the most common 40 ft layout; saildrive options narrow above 25 kW.
  • Plan for 5–7 kW shore charging to refill in a single overnight stop.
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Frequently asked questions

40 ft sailboat — common questions

Quick answers to what most owners ask before starting a repower.

Why go 96 V on a 40-foot sailboat?+
At 25–30 kW continuous on 48 V you're pulling 500+ A in steady state, which means cable cross-sections approach 120 mm² and bus bars become awkward. 96 V cuts current in half — cabling, fusing, and connectors all get cheaper and easier.
How much battery do I need for offshore work?+
30–45 kWh is the realistic minimum. That gets you 4–5 hours of motoring at cruise speed with reserve — enough for harbour entries, short calms, and battery-only operation when wind dies.
Is hydro regen worth it on a 40-footer?+
Yes if you do passages. At 7+ kn under sail you can recover 200–700 W per drive, which adds up over a multi-day passage and offsets house loads + occasional motoring.
What charging power should I plan for?+
5–7 kW from shore is the sweet spot — fills a 35 kWh pack overnight on a standard high-amp marina connection. Shore power inlets sized for 32 A AC give you headroom.
Shaft drive or saildrive on a 40 ft electric repower?+
Most 40 ft electric repowers stay shaft drive — saildrive options narrow above 25 kW and shaft installations reuse more of the existing infrastructure. New builds increasingly choose pod or saildrive electric for vibration and packaging reasons.
Other segments

Different boat?

30 ft sailboat35 ft sailboat40 ft catamaranElectric launchTrawler yacht

Size your 40 ft sailboat now

Wizard pre-filled with realistic defaults for this segment. Free to run; PDF from €29.

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