I remember being completely new to narrowboating and looking around at second hand narrowboats for sale. The broker might kindly lift up the deck boards so that I could get a good look at the engine and I would nod sagely, and try to pretend I knew what I was looking at. I still don’t know a huge amount about boat engines, but the following basic tips will give you an overview of what’s going on under the deck boards or in the engine room.

Keep Your Engine Happy

Basic engine maintenance of a modern narrowboat engine will include checking the oil and water levels and topping up as required. Filters will need changing now and then and the alternator belt needs tightening or changing sometimes. If you’re not very technical (like me!) you can pay a local marine engineer to give your engine a service. When we lived aboard we had the engine serviced about every six months. We always chose an engineer who came with a good ‘word of mouth’ recommendation on the ‘towpath telegraph’.

Cooling Systems

Most engines use a sealed water-coolant system. The water passes through a heat-exchange panel (skin tank) built into the inside of the hull below the waterline, then returns back to the engine. Air-cooled engines draw colder air from outside the boat using ducting. The hot air is then released the same way at the other side of the boat.

Older boats occasionally use raw canal water, drawn through the hull under the waterline. It takes the heat from the sealed system in a heat exchanger and then is expelled through the hull above the waterline. In this system there will be filters or mud boxes which will need regular cleaning.

No Clutch Required

Yes, here in narrowboat world we have both gears – forwards and backwards! Power from the engine is transferred through a gearbox to the propshaft and then the propeller. So the engine needs to be mounted centrally and as close to the propeller as possible, to keep the length of the prop shaft to a minimum. (A less common arrangement is where the engine powers a hydraulic pump, which means the engine does not need to be in line as no prop shaft is used. So the engine could be placed anywhere in the boat.)

Domestic Electrics

As well as supplying power to the propeller the engine also supplies electricity to supply the domestic needs of the cabin accommodation. The alternator charges both the starter battery and the leisure batteries. With a high powered engine you could have two alternators; a small one to charge the starter battery and a larger one to charge the bank of leisure batteries. You may also choose to fit an alternator booster, or battery management system,which can increase the amount of charge that can be put into the batteries.

What’s Your Favourite Engine?

When you are looking for a canal boat for sale there is a huge variety of engine choices, of varying ages. Popular vintage engines for enthusiasts of traditional narrowboats are Gardner, Lister or Russell Newbury. Find out more in this article: Older Boat Engines: Snog, marry, avoid?

However, since the 1990’s diesel engines have become more advanced, refined and complex. Popular makes are now Lister, Isuzu, Vetus, Kubota, Beta Marine, Barrus, Lombardini, Yanmar, Nanni and Thornycroft. Checkout Modern Boat Engines: Which is best?

If you browse our list of second hand narrowboats for sale you can get a good look at some of the different types of engine available in the photographs. If you have any particular questions Phil is always happy to help.


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