Electric Boat Motors: Types, Power, and What to Look For

Electric boat motors have come a long way from the trolling motors bolted to the transoms of bass boats. Today, the electric marine motor market spans everything from 1 kW pod drives for tenders to 222 kW inboard systems that rival the performance of large diesel engines. As the global electric boat market grows toward an estimated USD 10.6 billion by 2031 (MarketsAndMarkets), motor technology is advancing rapidly, and Australian boaters have more options than ever. Here is what you need to know to navigate the choices.

Types of Electric Boat Motors

Electric marine motors fall into three main categories: outboard, inboard, and pod drive. Electric outboards look and mount like their petrol counterparts but replace the combustion engine with an electric motor and controller. Brands like ePropulsion offer the Navy series at up to 6 kW, powerful enough for tenders, dinghies, and small fishing boats. These are self-contained units with integrated controllers, often with a tiller or remote throttle option.

Electric inboards are installed inside the hull and drive a shaft or saildrive. German manufacturer Torqeedo offers inboard systems up to 100 kW, suitable for cruisers, sailing yachts, and larger powerboats. Inboard systems typically deliver higher sustained power and are better suited to heavier vessels, but they require professional installation and hull penetration for the prop shaft.

Pod drives sit below the hull and combine the motor, gearing, and propeller in a single underwater unit. They are popular in catamarans because each hull can have its own independent pod, providing excellent manoeuvrability. Pod drives are also cleaner to install than shaft-driven inboards and can be rotated for steering without a rudder.

Understanding Power Ratings: kW, HP, and Equivalent Thrust

One of the most confusing aspects of electric boat motors is comparing their power to petrol equivalents. The straight conversion is 1 kW equals approximately 1.34 horsepower. So a 5 kW electric motor is nominally about 6.7 hp, and a 10 kW motor is about 13.4 hp. On paper, those numbers look modest compared to the 150 or 200 hp outboards bolted to many Australian runabouts.

But the raw conversion misses the point. Electric motors deliver what the industry calls equivalent propulsive power, usable thrust at the propeller, far more efficiently than combustion engines. A petrol outboard wastes 70 to 75 percent of its fuel energy as heat, noise, and mechanical friction. An electric motor converts 85 to 95 percent of its input energy to shaft rotation. The result is that a 5 kW electric motor delivers propulsive thrust comparable to a much larger petrol unit, particularly at displacement and semi-displacement speeds where most recreational boating occurs.

Leading Electric Motor Manufacturers

Several manufacturers are leading the charge globally, and most are now available through Australian distributors. Torqeedo, the German pioneer, offers the widest range, from the compact Travel series for dinghies through to the Deep Blue 100 kW inboard. Their systems integrate battery, motor, and controller with a polished user interface and GPS-linked range prediction.

ePropulsion, from China, has disrupted the market with aggressive pricing and solid build quality. Their Navy 6.0 delivers 6 kW in a package that weighs significantly less than an equivalent petrol outboard. For small to mid-size vessels, ePropulsion offers an excellent value proposition. Their Spirit 1.0 series is particularly notable for its maintenance-free design: there are literally no scheduled service items.

Norwegian company Evoy is pushing the performance envelope. Their Storm series delivers 222 kW, approximately 300 horsepower, with only four moving parts and an IP66 waterproof rating. The Evoy system can get a large sportboat on the plane and keep it there, proving that electric is no longer limited to slow displacement cruising. At the other end of the spectrum, Australian-distributed brands are growing rapidly, with five dedicated electric marine distributors now operating across the country.

What Cat Cruisers Uses and Why

Cat Cruisers vessels are fitted with E-Class electric motors, twin 5kW units in the 650 model, and twin 10kW units in the 750 and 870 models. We chose this configuration for a specific reason. The catamaran hull form requires roughly one-third the power of a monohull to achieve equivalent cruising speeds, so we do not need the brute force of a 100 kW or 200 kW system. Our twin 5kW motors deliver smooth, quiet propulsion with a six-hour runtime on a single charge, more than enough for a full day on Australian waterways.

The twin motor setup also provides redundancy and manoeuvrability. If one motor develops an issue, the other can bring you home. And for docking and tight-quarters handling, independent thrust to each hull is far more precise than a single-engine monohull with a rudder.

How to Choose the Right Motor for Your Boat

Selecting an electric motor comes down to four factors: vessel weight, desired cruising speed, battery capacity, and usage pattern. Heavier vessels need more power. Higher speeds demand exponentially more energy due to the cubic speed-to-power relationship. Larger battery banks extend range but add weight. And your typical trip profile, short blasts versus long cruises, determines where the sweet spot lies.

For most Australian recreational boaters, the optimal electric setup prioritises efficiency and range over top-end speed. That means matching the motor to the hull rather than overpowering it, using a propeller sized for cruising speed rather than sprint speed, and keeping weight down wherever possible. It is a different design philosophy from the petrol world, where horsepower is king: in electric boating, efficiency is the currency that matters.

If you want to see how a purpose-built electric catamaran handles on the water, and understand why motor selection is just one piece of a carefully integrated system, reach out to Cat Cruisers at catcruisers.com.au/contact. We are always happy to talk through the engineering with fellow boating enthusiasts.