Narrowboat Heating Part 1 – Stoves

By Tim Davis Onboard Solar

As a long term live aboard and ex boat builder I have been involved with many different heating systems over the years. The aim of this article is to look at all the options and to give some insight into the relative advantages and disadvantages of each of the different options.

When we look at heating systems on a  boat we are generally considering two things.

  1.  Heating the cabin space
  2. Heating the domestic water

First, let’s tackle the heating of the cabin. This broadly divides into two common methods.

  1. The solid fuel (or “multi fuel”) stove
  2. Some form of central heating

Part 1 – Solid Fuel Stoves

Let’s start with solid fuel stoves. The first point to make here is that heating using a solid fuel stove is generally the most reliable way of heating the cabin space. The vast majority of boats out there have a stove in the saloon area. Traditional boats with a back cabin will almost certainly have a small cooking range just inside the aft doors on the port side.

In the days of working boats when this was the only accommodation this would have been the source of heat, hot water (via a kettle) and cooking and would have been used 24 hours a day all year round. Many historic boats that have been converted by having extra cabin added over the hold space retain this range as do newer boats built in a replica style to a vintage boat.  This can be an advantage – in my boat for example which is a replica BCN tug, I have a stove in the saloon and a range in the back cabin.

The solid fuel stove is generally the most reliable and effective source of heat in a boat. Once up to temperature the saloon is kept very warm. It is a dry heat too, sucking in any moist air from the cabin and effectively drying it out so and condensation is quickly dispersed. Boat stoves are of the multi fuel variety which means they can burn coal and wood.

For the most effective heat a mix of the two works well. A bed of coal to start with then use logs on top once it has got well under way. Care needs to be taken in the choice of both the coal and the logs though! Coal generally is available as either “house” coal or “smokeless” and within smokeless there are many different makes.

The house coal is traditional coal that has been used for centuries. It lights very easily and quickly and gives a very good heat with lots of flame BUT gives a lot of smoke which, depending on where you moor, might cause problems. This also means that both chimney and fire get quite sooted up and thus need regular brushing and cleaning.

The general feel of using house coal is that it is quite dirty all round.  House coal also does not tend to stay “in” very well – that is, it does not stay alight all night as it’s a much quicker burn.

Smokeless coal however comes in the form of manmade “briquettes” which are smooth in appearance. These take a lot more effort to light so lots of kindling wood and paper or firelighters are needed to get it going. It also takes a lot longer to come up to temperature, once there though it will burn for hours on end.

Normal procedure is to get the fire up to temperature with all the vents open then close the vents right down so the fire just simmers with a red glow. There tends not to be much in the way of flames with smokeless coal but it is very clean burning compared to house coal.

I tend to have both house and smokeless in. I use the house coal to get the fire up quickly and easily, then add smokeless – this is a good mix. To enhance smokeless coal a log or two can be added to a hot fire in the evening to give flames and a rapid boost of heat. Logs of course have the great advantage that you can find them close to the towpath and collect for free. However beware!

It is important that logs are well “seasoned” that is left to dry out all of the liquid sap that was present when the wood was growing or “green”. It takes around a year to season logs but often you will come across trees by the cut that have blown down and may well already be seasoned.

You can soon tell if they are seasoned enough when you saw through them. If they are seasoned the saw will cut trough like butter with very dry sawdust if not then you will feel the saw bind up and have a very damp like sawdust in which case they will need to be kept for next year.

You will also notice the off cut log is very light in weight. Alternatively of course, if this foraging for logs all sounds a bit much, you can buy logs ready seasoned either in net bags or by the load which is cheaper (When short I have looked in news agent windows wherever I am moored – you often see signs for people offering a load of logs for not much money.

Non seasoned logs will burn, but not as well as seasoned logs and they will cause a nasty sticky tar which runs everywhere, often down the inside of the chimney and onto the roof and down the side of the boat! There is a new type of manmade log available now which is made of compressed wood shavings. I tried some this year and they were very good and not too expensive.

Types of Stove

Morso SquirrelThere are many different makes of stove. You may have heard of Arrow, Morso, Torgem, Boatman to name a few. They all work in the same way and usually have two vents on the front, one below the fire which must be fully open to light the fire and one above the glass which acts as an air wash to help clean the glass. Which one is best?

This is a question I am often asked.

In my experience the Morso Squirrel seems to be excellent. It has a good size so can hold a lot of fuel, it has good vents so draws really well which is important when lighting and has two doors the bottom, one of which can be opened to rapidly assist in the lighting process.

Another good one is the Corner Bubble multi fuel. This is an unusual triangular shaped stove that sits neatly in a corner of the boat and again burns very well. At the budget end of the market is the Boatman Stove made by Northern Fabrications. A simple little stove but one that burns really well and takes up a small amount of space.

corner bubble stoveA good tip from old working boatmen is always have a kettle on top of your stove – it means you’ve always got a bit of hot water for tea or washing up – very useful I find.

What about heating the rest of the boat?

A solid fuel stove outputs a lot of heat and will comfortably keep the saloon and immediate area very cosy indeed, but what if you want heat at the other end of the boat where the bedroom typically is?

The first important “must have” accessory is the “Eco Fan” This is a two or three bladed fan that sits on a stand on the top of the stove. It uses technology called a “Peltier” plate which generates electricity from heat to drive a small electric motor that turns the fan. It very effectively directs the heat away from the stove and “spreads” it around the boat. A small boat of say 30 to 40 ft with a stove and eco fan would have no problems heating that entire cabin space.

There is a new stove fan available that uses a tiny heat driven piston engine (a Sterling engine). A friend has one and it is very impressive with the joy of a little engine driven by heat from the fire (I know – boys toys!).

Eco Fan

Back Boiler

Another way of spreading the heat is to have a back boiler on the stove. This is simply a steel tank with an inlet at the bottom and an outlet at the top. The stove is connected into a circuit of radiators – standard household type radiators – and filled with water via a small header tank at the end of the pipe run.

This system can be setup in one of two ways; gravity fed or circulation pump. The gravity fed system required large bore pipe work (28mm typically) and has to be setup very carefully so the hot water leaving the fire from the outlet at the top rises away from the fire and the return to the fire drops via a gentle slope back to the inlet at the bottom of the fire.

There is quite a bit of “science” behind getting a gravity fed system to work well and not boil when the fire is too hot, so it is not for the faint hearted!

More common these days is a pumped system. Here the pipe work can be kept hidden low down with a small 12v pump located close to the inlet of the fire (the bottom) and pumps water towards the fire. These work reliably but have the big downside of consuming power and of course must be switched on the whole time the fire is lit otherwise the water will boil and then explodes out of the header tank (which is normally located in a wardrobe!).

Back boilers are great. On a long boat with many cabins they work very well BUT as a user of them you need to be aware of them potentially boiling. It is possible to rig up a temperature controlled switch that will turn the pump on when the fire is hot enough and turn it off when it cools. I highly recommend this if you have a pumped back boiler system – it makes it much easier to manage!

It’s also important to have a simple bleed valve at the hot water outlet of the fire to make it easy to bleed off any stream that builds up – I use a simple drain cock for this purpose. See diagram showing the layout of a pumped back boiler system.

Back Cabin Ranges

Epping StoveThere is another way to heat the whole boat. Use the stove in the saloon to heat that part of the boat. Then if you have a traditional, vintage or replica type boat, light the range in the back cabin as well! I have this arrangement on my boat and sometimes have both stoves lit but it does get quite expensive running two

The range prefers to run on coal rather than wood (apart from lighting of course) and has the great advantage of a cooking plate and a small oven. On a cold winters day its great standing at the tiller with a range just inches in front of you perhaps with a casserole in the oven! One of the most popular ranges you will see is the Epping.

Oil Stoves

Another alternative to the solid fuel stove is the oil stove. This looks the same from the outside as a solid fuel stove, and they are available with and without a back boiler just like a solid fuel stove.  Popular makes are the Bubble (from Haworth who also make the solid fuel Bubble) and Kabola to name two.

The main difference is these stove run from the same diesel oil that is used to propel the boat. They are often fitted with their own tank separate from the main engine tank and often located in one of the bow lockers. These stoves were very popular for a time around 10 years ago when diesel was very cheap (I recall it was about 19p a litre then – happy days!). They are called a “natural draft” oil burner.

The main problem with diesel oil is it is actually difficult to light  – if you drop a match in diesel it will go out. These diesel stoves work by allowing diesel to drip feed onto a tray inside the stove, this is then lit using either a piece of tissue paper or better still breaking up a fire lighter into small pieces and using a small piece to start the fire. Basically you light the piece of fire lighter and drop it into the stove, drop in a cage called the catalyst which will shape the flame once its lit, then turn the diesel tap on, as the diesel slowly reaches the firelighter it heats and the vapour ignites.

This can be a bit fiddly and there is a definite knack to getting a diesel stove going! Once lit you have a tap allowing you to vary the height of the flame, however care must be taken as a very high yellow flame will cause a lot of sooting up inside the stove.

Compared to a solid fuel stove the heat is less too. In part because of the fiddly lighting process and the need to clean the fire out after use which is quite messy coupled with soaring diesel prices mean this type of stove has become much less popular and many boats have replaced them with solid fuel types which is not difficult as they are physically very similar. Indeed a corner Bubble oil stove could be replaced with the much better corner Bubble solid fuel stove with ease. It’s important to consider the issues with diesel stoves when buying a used boat.

Part 2: Narrowboat central heating systems

Useful Information
Paul Smith

After six and a half years living on a narrowboat on England's inland waterways, Paul and his wife Cynthia wandered Europe by motorhome during the winter, and on the Dutch and French waterways in the warmer months on their 35' Dutch motor cruiser. However, the pull of England's muddy ditches proved too much for them. Now they're back where they belong, constantly stuck in mud in a beautiful traditional narrowboat.

pearley - Thursday,17 January, 2013

A good article Tim but you’ve brushed lightly over the ‘smokeless’ bit. 

I have read on various forums that boats are exempt from the smokeless zone regulations but if you don’t want to upset your neighbours on land, then they should be observed.

There have been several accounts where complaints have been made to the authorities. In fact, one of the reasons given for changing the VMs at Islington to residential is of excessive smoke from boaters.





diannecollins - Monday,11 March, 2013

Hi there wondered if anyone had tried the straw logs, i saw them at the Crick boat show last year, they are quite expensive but wondered what they are like to burn ?


Paul Smith - Monday,11 March, 2013

Waterways World reviewed the various stove fuels in their March 2013 edition. They burn quite hot and clean but, like wood briquettes, don’t burn for very long. They’e OK for a quick burst of heat (and OK if you have dry storage space for them but won’t stay “in” (alight) overnight. I’m afraid that there’s no effective alternative to coal briquettes. I did my own unscientific but practical and effective stove fuel test here.


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