The province of Ontario in Canada provides a huge range of boating opportunities, from historic man-made canals to more than 250,000 inland lakes, the 30,000 islands archipelago of Georgian Bay, to near-oceanic conditions on the vast Great Lakes.

Naturally, no single vessel can be ideally suited for all these waters: sailboats, large powerboats and cruisers are at home on the Great Lakes; houseboats and smaller cruisers on the canal; and canoes, small powerboats, sailboats, and pontoon boats can best find their way around the archipelagos and inland lakes.

Nevertheless, when making the leap from canoeing to the acquisition of a powered vessel, I wanted an easily trailerable craft that would enable as broad a spectrum of family boating as possible.

In addition, coming from the silence and eco-friendliness of a canoe, I wanted to minimise the fossil fuel impact – which for the sailors among the readers would mean a sailboat, of course!

However, finding the art of learning to sail a bit daunting, and the prospect of trailering a sailboat a bit too cumbersome, I set about searching for a suitable hull for a hybrid electric vessel – to allow silent electric cruising on the canals and around the marinas, and hybrid gasoline/electric propulsion in rougher water and to cover larger distances – common in Canada! – at higher speeds.

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The discussion you often find is around electric boats versus gasoline boats, but mixing outboard types is also feasible and, I think, a good compromise to maximise flexibility in energy use.

Hull considerations

The first question was that of a displacement versus planing hull. Clearly, for electric propulsion, displacement would have been the way to go, as the most efficient hull would be needed.

But powering along at slightly higher speeds seemed attractive to me; as a relative newcomer to power boating, I figured this would give some sense of security due to the ability to head to shore if the weather should turn quickly.

I therefore decided on a trailerable planing catamaran as an efficient and yet stable planing hull which might also do reasonably well in displacement cruising mode.

Interestingly, despite extensive research, I could only find potentially suitable small, light, yet affordable catamaran hulls in Australia, New Zealand, South Africa, and the UK – so when Kiwi came up for sale in the UK, I bought her immediately without further inspection.

A 2003 PowerCat 525 Cuddy cabin built in Cornwall, she had spent her life as a private fishing boat around the Isle of Arran, Scotland and was equipped with two Yamaha F15 outboards.

Kiwi arrived in Canada after a truck journey to Glasgow; container ship voyage via Liverpool, Antwerp, and Bremerhaven to Montreal; cargo train to Toronto; and a flatbed truck the rest of the way just before Christmas and Covid. Refitting Kiwi in our garage helped keep me sane during those long Covid lockdowns.

Electric propulsion

The first order of business was installing the electric propulsion system. I chose an ELCO EP-20 48V outboard clamped between the twin Yamahas onto the transom. While this location does cause some spray when zipping along on the plane, it is not very severe.

This motor apparently has maximum thrust comparable to a 20hp petrol outboard, but that’s at full throttle which means a draw of 180A at 48V – a rate which would quickly drain a battery bank.

So the electric outboard’s petrol ‘equivalent’ practical performance should be considered when being run at a sustainable level of current draw, which in this case is roughly at 30-40% of full throttle.

Battery power

The Achilles’ heel of electric boating remains the batteries, which have a much lower energy density than fossil fuels.

To keep the weight down, I chose lithium-ion phosphate batteries (Lynac Lithium Technology) instead of Absorbent Glass Mat (AGM) – and while I could have saved a few kilograms with a single battery pack, I wanted to mount the batteries along each side to keep the main cuddy free to use as sleeping quarters.

To minimise wiring runs, I installed four 13V 240Ah batteries in series instead of parallel 48V units, using balancers compatible with the batteries’ built-in battery management system (an absolute must for safety). This gave me a 12.7kWh total capacity at a system voltage of 53-54V, at a total weight of 120kg.

There are two ways to charge the batteries: via an onboard NOCO charger running on 120V shore power and giving 16 charging amps at the system voltage, or with an external Elcon PFC5000 charger fitted with the North American J1772 input and running at 240V, for quick-charging the system at roadside electric automobile charging stations when the boat is on the trailer.

The chargers and wiring were fitted into the existing deck box. It was all rather straightforward for an amateur like myself with only a basic knowledge of boat wiring and circuits, frequently checking wire gauge and load charts, occasional glances at sections of the American Boat and Yacht Council code and helpful websites like newwiremarine.com

Weighty modifications

The transition from fishing runabout to overnight family cruiser compliant with Canadian pleasure craft boating regulations, required significant other modifications. This all added weight, but I used ¼ in exterior grade softwood plywood and aluminium where possible.

The catamaran hull’s forgiving seagoing characteristics were helpful here to manage the weight. A few drill samples suggested to me that the condition of the existing transom was not good enough to support the three motors, so I replaced the transom wood to be on the safe side.

My list of new kit was quite lengthy:

• VHF radio with AIS and GPS
• Deck and cabin lighting
• Horn
• Additional navigation lights (to comply with Canadian regulations)
• Speedometer
• Depth finder
• Analogue ammeter and digital battery monitors
• A variety of fuses and fuse boxes for the separate (apart from their common ground)
• 12V, 48V, and 120V shore power electrical systems
• Throttle for the electric motor
• Shore power inlet and ELCI panel with ground fault circuit interrupter outlets and failsafe galvanic isolator
• Automatic bilge pumps in both sponsons
• A Panasonic Toughpad – second-hand from eBay – which got its GPS feed from the radio via a NMEA to USB converter – to be used as the navigation system

All of this required the addition of a house battery, also lithium, which is charged either via shore power, solar panel input, or from the starboard engine via a DC-DC converter.

To keep the batteries cool, the cabin windows were externally covered with acrylic-compatible reflective film, and the front cabin window converted to an opening hatch.

Meanwhile, a custom camper enclosure, self-contained head, and a captain’s seat which opens to reveal a compact galley – complete with sink, pop-up electric tap, and concealed fresh-water and grey water tanks – and the large bed in the cuddy, together with the bench on deck, allow short overnight trips for our family of four.

To add room for my feet when sitting at the controls – rather than standing as the original design called for – a $10 stainless steel gravy container from a restaurant supply store was installed sideways into the cuddy wall!

Sea trial

After a nerve-wracking first trip during which one of the old carburetted outboards stalled on open water on Lake Huron, I replaced the outboards with a pair of new fuel-injected Yamaha F25’s, to boost power, reduce emissions, and not add much weight.

Propeller pitch had to be reduced from stock 11in to 9in of pitch (3-blade) on the Yamahas, while the electric outboard turns a high-thrust four-blade 5in pitch kicker propeller.

Fully loaded with camping gear and four people, the top cruising speed on plane with all three engines full throttle is 15 knots, and without gear and just one or two on board we can hit 18 knots.

The addition of two hydrofoils to the petrol outboards was necessary to successfully counter the bowrise which occurred, likely due to the weight distribution. However, moving the batteries more forward negatively impacted the handling in electric-only displacement mode.

An aluminium rudder was also added to improve manoeuvring with the low-power electric motor, with the rudder mounted upside down so it would rise out of the water when on the plane.

Verdict

Around the marina, docking, getting the boat on or off the trailer, and for relaxed cruising on the Trent or Rideau canals at around 4 knots we use electric power alone, and power-tilt the Yamahas out of the water to minimise resistance.

At this speed the electric motor draws around 60-70A at 53V, giving a runtime of three hours and a range of 25km. At an even more leisurely pace of 3 knots, power draw is nearly half, and theoretically the range would exceed 40km although we have not had the patience to try that yet.

Kiwi’s ‘sweet spot’ seems to be around 7 knots, with the electric motor drawing 50A and the petrol outboards very quietly running at 2,800rpm, with low fuel consumption. This is the minimum speed and thrust at which Kiwi stays on the plane with four people aboard in calm conditions.

Certainly, wind and waves may always require a bit of an adjustment, but as we gain experience in experimenting with the relative positions of the three throttles and moving the weight around the boat, we continue to enjoy exploring more of what Ontario’s lakes, canals, and rivers have to offer while trying to do our part to minimise the environmental cost of our fun. And as a conversation starter (“I’ve never seen a boat like that in my life”) Kiwi never disappoints!

Costs

Electrification

Elco EP-20 electric outboard with controls: £4,000
Lithium battery bank: £4,000
Boat hull with original engines: £6,950
New twin Yamaha F25s after selling old F15s, net: £6,000

Relocation

Transport from UK to Canada: £3,000
Wiring for propulsion system, fuses, charger, battery monitor: £1,200
Radio, call sign registration fees, navigation equipment, lights, horn, materials for transom and galley: £1,500

Total: £26,650

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This feature appeared in the August 2023 edition of Practical Boat Owner. For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

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