Best power for inland 36 foot narrowboat

[Star and Otter]

I’m looking for an idea as to the sensible minimum power for an engine on a 36 foot narrowboat for river and canal use. I’m still looking to buy but would like to know what to look for. Thanks!

[Alan de Enfield]

Boats with just 1 horse power worked the canals for over 100 years.

[Machpoint005]

Absolutely right, but a 1hp engine won't get a 10 tonne boat moving.

 

 

[booke23]

I wouldn't get hung up on things like minimum horse power. Find a boat you like and buy it.

To answer your question, Beta marine would recommend a 25hp or 30hp engine for a 36ft boat. 

[MtB]

5 minutes ago, Alan de Enfield said:

Boats with just 1 horse power worked the canals for over 100 years.

 

Indeed. There was a thread here long ago where somebody posted credible figures to demonstrate a horse has a power output of some 8hp! 

 

 

[Tony Brooks]

I found about 35 hp on a 54 footer perfectly adequate. Unless you buy an old  banger I doubt it would ever be under powered.

[Jen-in-Wellies]

10 hours ago, MtB said:

 

Indeed. There was a thread here long ago where somebody posted credible figures to demonstrate a horse has a power output of some 8hp! 

 

 

Two hp per leg. These were for pulling loaded 70' narrowboats though. A 35' boat would be fine with a two legged 4hp horse. 😀

[Alan de Enfield]

12 hours ago, Machpoint005 said:

Absolutely right, but a 1hp engine won't get a 10 tonne boat moving.

 

 

 

I think it would - it would not be a quick start, and 'braking' would be difficult but it would work.

 

You have picked an interesting 'number', as the recommendations for towing a boat are a maximum of 10 tons per hp

Edited March 6, 2022 by Alan de Enfield

[BilgePump]

10 hours ago, Machpoint005 said:

Absolutely right, but a 1hp engine won't get a 10 tonne boat moving.

 

 

I'd suspect that even a baby seagull outboard could get the boat moving in a flat calm, but it certainly wouldn't be much use at stopping it. A grown adult can pull along a fair size narrowboat but there's a lot of skidding and being dragged along the towpath when it comes to bringing it to a halt once it has built up any momentum.

 

We had 35hp on a 60ft boat that started life as a 45ft. Was plenty for canal use but felt that it was possibly just a bit short of ponies to punch against a serious tide on a river, once the shell was extended. Could have been hard work for the engine. Previously we had 25hp I think on a 35' boat. Based on that I'd reckon the suggested 25-30hp sounds fine for a 36' boat.

 

For secondhand boats, unless the engine is obviously underpowered then it's going to be about its condition, age, hours of use, maintenance, make and availability of spares and engineers, reliability etc. Rare vintage engines look fantastic but are for the knowledgeable enthusiasts. The rest of us should just look for well maintained, moderate hours, modern engines that are well understood by engineers who may be tasked to work on them. There are still plenty of BMC engines out there with life in them if they haven't been ragged and never maintained. 

[mrsmelly]

11 hours ago, Star and Otter said:

I’m looking for an idea as to the sensible minimum power for an engine on a 36 foot narrowboat for river and canal use. I’m still looking to buy but would like to know what to look for. Thanks!

Its bee answered, but my twopenneth. My first narrowboat was a 56 footer, we lived aboard that one for five years. It had a hand start only ( non of this girlie electric nonsense ) Lister Lr 2 a fairly knackered one. iirc they are 9hp when new. We traveled north to south and east to west more than once covering Ripon, down to London and Bath and everywhere inbetween. The only time my backside was going dutbin lid, wagon wheel, dustbin lid was on the tidal Trent. However these days any modern 2 or 3 pot engine will get a 36 footer on the plane. As others have said, hp is more important for stopping.

[MtB]

16 minutes ago, mrsmelly said:

However these days any modern 2 or 3 pot engine

 

I can't think of a modern 2 pot widely used in narrow boats. 

 

Although there is quite a strong argument that a Gardner 2LW is a modern engine, not a vintage as some people think. 

[mrsmelly]

4 minutes ago, MtB said:

 

I can't think of a modern 2 pot widely used in narrow boats. 

 

Although there is quite a strong argument that a Gardner 2LW is a modern engine, not a vintage as some people think. 

Beta do or certainly did a two pot just for one old bean. Gardner  did lovely bus engines.

[peterboat]

Just now, mrsmelly said:

Beta do or certainly did a two pot just for one old bean. Gardner  did lovely bus engines.

My old bathtub has a 13hp lombadini in it, adequately powering it.

[OldGoat]

As the OP can see there's a lot of banter around - because there's not of information in the OP's question. to give a more considered answer 'we' need more information  - 

location

cruising range

use of boat

type of boat

yada, yada, yada.

 

Regardless - a small Beta engine will cope with 'whatever' - second alternators, freshwater cooling, whatever

You'll pay mebe a bit more, but you'll have a wide choice of alternators, cooling type, transmissions - all from one source. 

 

ps: whereas a 'gull will push a canal boat along and have a sensible propellor; it won't stop the boat or go backwards.

For a budget engine a Lister woulod do - noisy, lasck of torque and take a lot more engine bay space...

 

 

 

 

 

Edited March 6, 2022 by OldGoat

[MtB]

4 minutes ago, OldGoat said:

As the OP can see there's a lot of banter around - because there's not of information in the OP's question. to give a more considered answer 'we' need more information  - 

location

cruising range

use of boat

type of boat

yada, yada, yada.

 

 

Also, budget. 

 

If the OP is having a new boat built with no limit on funds, suggestions will be different from if they are actually looking at 40 year old Springers for £15k.

 

 

[peterboat]

Just now, MtB said:

 

 

Also, budget. 

 

If the OP is having a new boat built with no limit on funds, suggestions will be different from if they are actually looking at 40 year old Springers for £15k.

 

 

The lombadini cost 825 squids secondhand with gearbox  and 192 hours on the clock! Ebay bargain ot what? The propeller had to be changed but again secondhand was cheap and a 500cc engine in a broads cruiser is economical which was what the new owners wanted 

[MtB]

3 minutes ago, peterboat said:

and a 500cc engine in a broads cruiser is economical which was what the new owners wanted 

 

That 10hp again! 

[peterboat]

1 minute ago, MtB said:

 

That 10hp again! 

It's supposed to be 13 hp it's a modern OHC engine fully marinised engine. It does remarkably well considering it replaced a 1500 BMC. As you know it had an electric motor in between times, which is in the big boat now.

[MtB]

21 minutes ago, peterboat said:

It's supposed to be 13 hp it's a modern OHC engine fully marinised engine. It does remarkably well considering it replaced a 1500 BMC. As you know it had an electric motor in between times, which is in the big boat now.

 

 

So are you saying you reckon a 13hp Lombardini would suit the 36ft NB the OP is seeking? 

 

Have to say I agree. My 21hp Kelvin pushes by 68ft boat around fine. My 57ft with the K2 is more like a speedboat! 

[peterboat]

Just now, MtB said:

 

 

So are you saying you reckon a 13hp Lombardini would suit the 36ft NB the OP is seeking? 

 

Have to say I agree. My 21hp Kelvin pushes by 68ft boat around fine. My 57ft with the K2 is more like a speedboat! 

Yes it would be fine the broads cruiser while light and boaty under water shape has a lot width. So a similar length narrowboat should be good 

[CIEL]

Yes, our 2007 36ft has a Beta 30 and once we had sorted out the propeller - it was well under propped when we took delivery - it has been up and down to Ripon from Selby having to wait at Boroughbridge for the water to drop a bit.  Gone in and out of Gloucester.  Had to hold mid Trent for 15 to 20 mins on not much more than tickover waiting for West Stockwith to let us in, yes we had let them know we were coming. Plus it handles anything our home river the Great Ouse throws at us when under caution.  So 30hp is plenty in our experience.

Chris

[David Mack]

23 minutes ago, CIEL said:

Yes, our 2007 36ft has a Beta 30 and once we had sorted out the propeller - it was well under propped when we took delivery - it has been up and down to Ripon from Selby having to wait at Boroughbridge for the water to drop a bit.  Gone in and out of Gloucester.  Had to hold mid Trent for 15 to 20 mins on not much more than tickover waiting for West Stockwith to let us in, yes we had let them know we were coming. Plus it handles anything our home river the Great Ouse throws at us when under caution.  So 30hp is plenty in our experience.

Chris

Makes you wonder how on earth a loaded working pair of narrow boats, with an all-up weight of 60 or 70 tons, managed with a single engine of around half that power!

[IanD]

2 minutes ago, David Mack said:

Makes you wonder how on earth a loaded working pair of narrow boats, with an all-up weight of 60 or 70 tons, managed with a single engine of around half that power!

They didn't move against strong streams on rivers? Or did so very slowly if going upstream?

 

On a canal with no current even 10hp or less is actually fine; when we hired the steamer Firefly in the 80's that had about 4hp flat out. Sure it took time to stop, but then horse-drawn boats couldn't stop at all...

[Tony Brooks]

3 minutes ago, IanD said:

They didn't move against strong streams on rivers? Or did so very slowly if going upstream?

 

On a canal with no current even 10hp or less is actually fine; when we hired the steamer Firefly in the 80's that had about 4hp flat out. Sure it took time to stop, but then horse-drawn boats couldn't stop at all...

 

Not so sure abut that.

 

A few years ago when I was moored at Windsor I watched a laden coal boat come storming up stream with a good bow wave and a cockscomb from the prop. There was no was I could have kept up with it and it sounded like a twin. I am sure it is the large diameter prop that is more efficient than the egg-whisks modern boats tend to use.

[IanD]

14 minutes ago, Tony Brooks said:

 

Not so sure abut that.

 

A few years ago when I was moored at Windsor I watched a laden coal boat come storming up stream with a good bow wave and a cockscomb from the prop. There was no was I could have kept up with it and it sounded like a twin. I am sure it is the large diameter prop that is more efficient than the egg-whisks modern boats tend to use.

 

You might be sure of it but any marine engineering book will tell you that you're mostly wrong... 😉

 

if the engine and prop are properly matched then speed though the water and bollard pull pretty much depend on engine power and not much else. A big slow prop is a little bit better (more efficient) than a small fast one but the difference is small, usually no more than 10%.

 

Of course if you compare an old boat with the engine putting out 20hp continuously bonking away at not much over 1000rpm (maximum rated rpm) with a modern 40hp engine which never runs at full power because the rpm, noise and vibration are too high to bear, you might think the old boat is better because it has a bigger prop 😉

Edited March 6, 2022 by IanD