Electric Narrowboats Guide

Electric mobility is everywhere, and Britain’s canals are no exception. 

With going electric on everybody’s minds, this guide examines what it means on the canals. How do all-electric narrowboats work, and how much do they cost?

Types of electric narrowboat

First, an important distinction. Almost all narrowboats have electric power for running lights, TVs, home appliances, etc. What we mean by an electric narrowboat is one that is also propelled using electrical power.

Electric narrowboats break down into three varieties.

All electric

This means there is no internal combustion engine aboard and no fossil fuels. A large battery bank powers an electric drive and all the onboard systems and appliances.

Serial hybrid

These boats have an electric motor to drive the propeller. But there is also a generator on board, which burns diesel or petrol to supply the electricity to recharge the battery bank.

Parallel hybrid

In this system, an electric motor is fitted to the prop shaft alongside the traditional internal combustion engine. The motor can drive the propeller using all-electric power for short periods or boost the main engine, just like in hybrid cars. This system is most commonly retrofitted to an existing narrowboat.

What are the benefits of an electric boat?

Have you ever noticed the smell of diesel fumes that follow you along the canal as you motor? Well, there’s no exhaust from an electric motor, so all-electric narrowboats keep you breathing easily.

This is good news for other canal users and wildlife and is especially welcome at pinch points, such as around locks and marinas. But it is also good news for the planet. Narrowboat engines burn an average of 1.5 litres of fuel per hour, emitting 4kg of CO2. According to usage, a typical four-hour cruising day makes 16kg of CO2 per day or several tonnes yearly.

But diesel also emits fine soot called particulates, which are thought to be bad for health, as well as oxides of nitrogen, which can damage your lungs. Then add in the coal or wood that many narrowboats burn for winter warmth and you have something of a smog.

An all-electric narrowboat eliminates those emissions using solar panels and shore power to fill a large battery bank. Everything from propulsion to dishwashers and heating then runs off the battery.

Even a serial hybrid dramatically reduces emissions of pollutants like CO2 and particulates. Electric power propels the boat, leaving a small, highly efficient generator to recharge the batteries.

See our other tips for a greener boat.

But electric power is not just cleaner. It is also nearly silent. So, for the first time, you can listen to the sounds of the countryside around you – rustling trees and birdsong. And you can converse with someone in the galley without shouting!

Lastly, going electric can free you from the tyranny of the fuel boat. No more hunting to find an open pump or queuing in high season. The solar panels will always keep the lights on, and charging points are available in marinas across the network.

How do electric narrowboats work?

Well, at one level, it’s simple. The electric motor draws power from a battery bank to turn the boat’s propshaft. This, in turn, rotates the propeller that moves the boat backwards and forwards.

Take the 58ft 6in narrowboat Wattway from Oundle-based Mothership Marine as an example. It has a 15kW electric motor running off 28.6kWh of lead-acid batteries. But the motor only uses an efficient 1kW of power to push the boat at 3mph. And that is plenty because the absolute speed limit on the canal network is only 4mph.

There are some important differences between the serial and parallel hybrid options. In a serial hybrid narrowboat, the electric motor is the only power source for driving the propshaft, drawing on batteries which may be topped up by a small generator hidden elsewhere in the boat.

In a parallel hybrid, the internal combustion engine is attached to the propshaft in the traditional way. It is the primary means of propulsion. But in addition, there is an electric motor fixed over (and sometimes around) the propshaft, such that it can boost the turning force of the main engine. It usually clutches in and out as you need it. Using pure electric power, you should also be able to manoeuvre slowly over short distances.

A clever side effect of the parallel hybrid is that the electric motor can also be used as a giant alternator, turning excess engine power into electricity to recharge the batteries, heat water, etc.

How far can you go between charges?

Range anxiety is familiar to electric car drivers, and the question of range comes up every time with electric narrowboats. It is hard to be precise because even the air’s temperature can impact battery performance, but it is possible to make some conservative estimates.

Mothership Marine reckons that its 15kW motors only need 1kW of power to get a narrowboat up to speed at 3mph. Your 28.6kWh batteries should be able to run the motor for 28.6 hours at this rate, giving a range of 85.8 miles (28.6 x 3).

Unfortunately, the chemistry of lead-acid batteries doesn’t work this way. A good quality lead-acid battery will allow you to use a maximum of 80 per cent of its capacity, but for long life, 50 per cent is much more reasonable. So that gives us usable power of between 14.3kWh and 22.8kWh. In range terms, that means 42-68 miles between recharges.

Beware, though: this would mean all your battery power goes into propulsion. If you use the same batteries for running fridges, hobs, and the hot tub at the bow, then your range falls accordingly.

On the other hand, Wattway also has 1.8kW of solar panels on the roof. On a sunny summer’s day without shade, this could put 6-7kWh back into your battery – enough for 20 miles of free motoring. So, if you’re prepared to navigate slowly in smallish hops, the battery can run indefinitely!

Recharging is easy

If the solar panels are not keeping up with the demands of your electric narrowboat – perhaps you’re on a shady stretch of canal, or the weather is poor – there are other ways to recharge the batteries.

The easiest option is to pull in at one of the network’s many marinas, where you can plug into shore power overnight. Of course, you’ll have to pay for this, but it allows you to have an unlimited shower or do some laundry ashore.

If the marina offers 16-amp Commando sockets, you can pump electricity back into your batteries at up to 3.8kW. The more standard 10-amp sockets are slower at 2.4kW. Either way, you can refill the battery during a good overnight stay. Just remember that lead-acid batteries need a period of slow trickle charging at the end of the charging cycle to keep them in good condition. That means it always takes a little longer than you expect.

Lithium batteries are the gold standard and are much faster all around. You can run them down to empty without damaging them and recharge them rapidly to full. They weigh around half that of lead-acid batteries and cost about three times the price. But if your budget allows, it’s a no-brainer!

To understand this, you need to know that a motor using 15kW of power for one hour will use up 15kWh of battery capacity. A 1.8kW solar array in full sun for an hour can theoretically put 1.8kWh back into the batteries.

Do electric narrowboats handle differently?

Handling an electric narrowboat is similar to a standard diesel-powered variety. You’ll need to factor in time and space to turn, as normal, and it also takes time to get up to cruising speed or bring the boat to a halt.

An electric motor makes a difference because it delivers power to the propeller much more efficiently. This can make it easier to handle an electric narrowboat when manoeuvring at close quarters and low speeds.

It’s all a question of torque or turning force. Electric motors deliver optimum torque across nearly their whole range of speeds from a standing start. Diesel engines, on the other hand, only give the best torque at around 2000rpm. At lower and higher speeds, you’ll burn much more fuel for less power.

Going all-electric – is it feasible?

Technically, it is possible to run an all-electric narrowboat. That is, a boat whose primary energy source is the batteries, which cover everything from propulsion to hot water. There is no generator, no wood stove – everything is electric.

But as figures from The Fitout Pontoon show, you would need a big battery bank and an even bigger solar panel array to make it work. They estimate that average summer use – motoring to a lunch spot, then on to a mooring for the night – would consume 30kWh of power each day. Living the same way during the winter with electric heating would munch through some 50kWh of power daily. That’s a lot!

For this to work, you would need as much as 50-100kWh of batteries and a fast charger at the pontoon. That’s why it’s often said that the all-electric narrowboat is best suited to weekend cruisers or those who spend several days in the marina between hops.

And the million-dollar question: how much does an electric narrowboat cost?

There’s no simple answer regarding cost. Narrowboats come in a range of different sizes, from around 30ft up to 70ft, and the more boats you buy, the more they cost. It’s the same story with the boat’s interior. The difference between a tired, old interior and a stylish one with all the mod-cons can be two—or threefold.

That said, there are lots of clues online. Mothership Marine says prices for its 57-62ft serial hybrid electric narrowboats start at £250,000 (inc VAT), including the fit-out of your choice. A new boat with all the technical systems in place but a bare interior (a ‘sailaway’ in narrowboating lingo) costs £150,000.

Ortomarine of Shenstone, Worcestershire, recently listed a 58-foot secondhand serial hybrid called Minerva for £190,000. The boat has been fully refitted in contemporary classic style and has a 20kW motor, 2.4kW solar panels, and a lithium-ion battery bank.

Ovation Boats breaks the pricing down easily. Its 27-42ft Hobbit range costs just £3,000 more with an electric motor instead of a diesel engine. If you want a generator, it’s another £13,000 and counts on £6,300 to £8,400 for solar panels. So, a full serial hybrid option costs about 20 per cent more than the diesel equivalent.

And the cost of charging the battery? Well, there’s the cost of the marina berth for the night – perhaps £20-40/night. Then, you’ll usually pay the unit cost of electricity – currently averaging around 22p/kWh. That means you could ‘fill up’ your Mothership for less than a fiver! Diesel for 14 hours of motoring would set you back over £20.

Specialist narrowboat insurance through Insure4Boats

If you're thinking about buying an electric narrowboat, then you may want to consider specialist narrowboat insurance for that extra peace of mind.

With Insure4Boats, the cover protects your boat against theft, accidental damage, malicious damage, and salvage charges.

You can also opt to include Third Party Liability and contents protection, so you have nothing to worry about when cruising the waterways.

Click here to discover more about how we can help, or get an instant online quote today.