How Far Can an Electric Boat Go? Range and Speed Explained
How far can an electric boat go on a single charge? It is the first question almost everyone asks, and the answer is more nuanced than a single number. Range in electric boating depends on an interplay of hull design, battery capacity, motor efficiency, speed, wind, current, and load. But with real-world data now available from a growing number of electric vessels worldwide, we can paint a clear picture of what to expect in 2026.
The Numbers: Real-World Range Data
Across the current generation of production electric boats, the median range sits at approximately 40 nautical miles on a single charge at economical cruising speeds. Most planing-hull electric boats deliver 30 to 50 miles at their most efficient cruise setting. That comfortably covers a full day of recreational boating for the vast majority of Australians: the morning trip to a favourite fishing spot, a leisurely cruise up a river system, or an afternoon of watersports and anchoring.
The standout performer is the Candela C-8 from Sweden, which achieves 57 nautical miles at 22 knots using computer-controlled hydrofoils that lift the hull above the water, dramatically reducing drag (Candela). During a widely publicised Mediterranean crossing, the Candela consumed just 40 kWh of electricity (costing roughly eight euros) while a conventional chase boat used 50 litres of fuel at approximately ninety euros (Candela). That comparison captures both the range capability and the cost advantage of electric propulsion when the hull is designed from scratch for efficiency.
The Cubic Speed-Power Relationship
Understanding range in electric boating requires understanding one fundamental physics principle: the speed-to-power relationship in boats follows a cubic curve. Double your speed and you need roughly eight times the power. Triple your speed and the power requirement increases by a factor of twenty-seven. This is why a boat that can cruise for six hours at 5 knots might only sustain 20 knots for forty-five minutes on the same battery.
This cubic relationship is not unique to electric boats. It applies to all watercraft. But in petrol boats, the massive energy density of fuel masks the inefficiency. You can carry 200 litres of petrol and burn through it quickly at high speed. With batteries, every kilowatt-hour is more precious, so speed discipline becomes the key to range. The sweet spot for most displacement and semi-displacement electric boats sits at 50 to 60 percent of theoretical hull speed, where the hull moves efficiently through the water without trying to climb over its own bow wave.
Why Hull Design Matters More Than Battery Size
It is tempting to think that range is simply a function of battery capacity: more kilowatt-hours means more miles. But hull design has a far greater impact. A well-designed catamaran requires roughly one-third the power of a monohull to achieve the same cruising speed. Patent literature and naval architecture research document drag reductions of 20 to 45 percent for twin-hull configurations. That means a catamaran with a 30 kWh battery can match the range of a monohull with a 50 kWh battery, while carrying less weight and costing less in battery investment.
Weight is the other critical factor. Every additional kilogram you carry requires more energy to push through the water. This creates a paradox with batteries: adding more battery capacity adds more weight, which reduces efficiency. There is a point of diminishing returns where adding another battery bank actually hurts range. Smart electric boat design finds the balance point where battery weight, hull efficiency, and desired range all align.
Extending Range: Solar and Charging Strategies
Solar panels can meaningfully extend range, particularly in Australian conditions. With northern Queensland receiving over 5.5 kWh per square metre per day of solar irradiance, rooftop panels on a catamaran can contribute meaningful energy while underway or at anchor. The Solar Sal 24 demonstrated what the industry calls infinite range at 5 knots with 1,440 watts of panels, meaning the solar input matched the power consumption at low cruising speed (Solar Sal). The French vessel Energy Observer has logged over 35,000 nautical miles on solar and hydrogen power alone.
For multi-day trips, charging strategy becomes important. The emerging DC fast-charging infrastructure (led by companies like Aqua superPower, which offers up to 350 kW charging, achieving 80 percent charge in 20 to 60 minutes) will eventually make long-distance electric boating practical. In Australia, the first marine DC fast charger has been installed at The Quays Marina in Church Point, signalling the beginning of a charging network. For now, though, most electric boaters charge overnight from a standard 15-amp outlet or marina shore power.
Range in the Real World: The Cat Cruisers Approach
The Cat Cruisers 650 is designed around the way Australians actually use boats. Twin 5kW E-Class electric motors deliver a six-hour runtime on a single charge at comfortable cruising speeds. That covers the typical day trip with margin to spare. The catamaran hull form, with its inherently lower drag, means we extract maximum range from every kilowatt-hour in the battery bank without needing the massive battery installations that drive up cost and weight.
And because our vessels are amphibious and trailerable, range takes on a different meaning. You are not limited to one waterway. Tow the boat to a new destination, charge it overnight at your accommodation, and explore a different stretch of coastline the next day. The range is not just what the battery holds. It is everywhere you can tow the vessel and plug it in.
Curious about how range works in practice for an amphibious electric catamaran? The team at Cat Cruisers is happy to walk you through the real-world numbers. Get in touch at catcruisers.com.au/contact.