Presiding wisdom on HP! What range of HP is best for 62ft narrowboat?

[Alan de Enfield]

4 minutes ago, ditchcrawler said:

This looks like 2 horsepower

 

Yer but  - thats is French Horsepower, not proper British Horsepower - you only have to look at a 2CV to see what French Horse Power looks like.

 

 

Of course you all knew this ..............................

 

2CV actually stands for “Deux Chevaux Vapeur” (in French).

In English, this literally translates as “Two Steam Horsepower”.

 

 

[Stroudwater1]

7 hours ago, Tonka said:

A desperate seller will tell it is OK just to get a sale. A longer test drive will tell you nothing unless the boat is on a river

Some sellers are decent though, have some faith 😊 we are still in touch with the vendor of our boat. 

[Francis Herne]

23 hours ago, MtB said:

Back in the day 1hp was enough.

Humour aside (and you probably know this), 1hp is approximately the continuous average power that can be maintained by a horse across a full day.

 

A horse working hard for short periods, such as getting a boat moving, can exert 10-15hp. It's no coincidence that early Bolinders etc. are in that power range.

An engine with a peak power of 1hp, as diesel engines are usually advertised, would be pretty hopeless in a narrowboat.

Edited May 15, 2023 by Francis Herne

[Mike Adams]

2 hours ago, blackrose said:

I never really understand why this old cliché is trotted out so often (pardon the pun). I don't know much about the history of the waterways but were single horses ever used to pull canal boats upstream for any distance? If they were I imagine it can only have happened on very gentle rivers so not really what the OP is asking about.

 

Pulling a boat from the bank is very different from driving a boat with a propeller. When you are tied up to the bank there is a force on the mooring ropes but no work is being done and no energy used however when going against the stream on a motor boat you need to expend energy just to stand still let alone make progress. It is much more efficient being towed from the bank. This was often the case on continental rivers where a low powered tug connected to chain on the riverbed could pull a string of barges against the current even if only slowly. The work required to move a boat towed by a horse is more interesting because the horse just standing there is not in theory using any energy.

My Grandfather used to work as a waterman on the Thames above Teddington with a horse towing timber barges to Kingston and beyond and he only had one horse to tow a lighter. The actual speed of the current near the bank can vary a lot but usually much less than that in the centre.

When I go upstream when the Thames is in flood I stick as close to the bank as I can but you do need some power to get through certain bridges which is probably the limiting factor for a narrowboat. 

I seem to remember the original way they calculated the power of a horse was with a horse gin lifting a weight but I don't think it was necessarily the maximum  power of a horse. I am sure a racehorse produces more than 1hp in a race.

[MtB]

8 minutes ago, Francis Herne said:

Humour aside (and you probably know this), 1hp is approximately the continuous average power that can be maintained by a horse across a full day.

 

Yes it was said it for humorous effect and I know it is deeply misleading, but the definition you outline doesn't quite ring true to me either. I'd have thought there was simply too many variables to state such a thing, ranging from how long the day was, how big the horse was and how hungry/willing it was. 

 

What I can say is I took my 68ft NB with long fine swims from Reading to Oxford many years ago on red boards all the way. 21hp at 750 rpm vintage diesel grossly over-propped and only getting up to 450rpm, so probably only 10hp actual work being done pushing the boat along. It was slow going and the slowest bit was getting through Osney Bridge which took about 20 minutes. 

 

I don't think the OP needs to worry, but if he were to tell us what the actual engine etc is in this 62ft boat he is looking at, I'm sure the board would barf up a load of opinions.

 

 

 

[Ewan123]

Theory aside, has anyone ever had/used a boat that was underpowered to the extent of it being problematic? I don't think I've heard of it happening (unless someone's trying to go up a river that's really just going too fast for safe passage in a narrowboat).

[ditchcrawler]

2 minutes ago, Ewan123 said:

Theory aside, has anyone ever had/used a boat that was underpowered to the extent of it being problematic? I don't think I've heard of it happening (unless someone's trying to go up a river that's really just going too fast for safe passage in a narrowboat).

Lack of cooling seams a bigger problem 

[IanD]

22 minutes ago, ditchcrawler said:

Lack of cooling seams a bigger problem 

 

The other frequent problem seems to be dirty fuel, with the unaccustomed rocking of the boat stirring up crud or water from the bottom of the diesel and making the engine stop.

 

Neither cause is a lack of power as such, for example I've never heard anyone with a 15hp Bolinder (Spey, Colonel...) complain that it was too slow on a river to be safe... 😉

[Richard T]

We have a 62ft boat fitted with a BMC 1.8 so a nominal max HP of around 38. This would be acheived at high revs. The reality is that the skin tank is undersized so running at max revs for more than a few minutes would cause the engine to overheat. However we do boat on the Soar and Trent when they are in amber and we know from experience how to manage the engine to avoid overheating. For example on leaving Beeston heading upstream we keep the revs low enough to make fair progress with the knowledge that as you approach Cranfleet the river narrows and is shallow and you have to increase the revs to counter the increase in current. Because we manage the revs we do not get overheating. It is really about getting to know the charecteristics of your boats power train.

Edited May 16, 2023 by Richard T

[blackrose]

50 minutes ago, Ewan123 said:

Theory aside, has anyone ever had/used a boat that was underpowered to the extent of it being problematic? I don't think I've heard of it happening (unless someone's trying to go up a river that's really just going too fast for safe passage in a narrowboat).

 

I think the main reason we don't hear of it happening is chiefly because most canal boaters venturing onto rivers have a general awareness of the limitations in the power and handling capability of their boats. I'm sure there are lots of underpowered boats that just sit on canal moorings and occasionally potter along which might struggle.

 

It really depends on where you're going. If you want to take a boat on the ebb tide down Thames though central London you better be pretty sure it's got enough power to turn into a 5 or 6 knot current and get you safely into Limehouse lock. Some canal boats would struggle and get swept downstream.

28 minutes ago, Richard T said:

We have a 62ft boat fitted with a BMC 1.8 so a nominal max HP of around 38. This would be acheived at high revs. The reality is that the skin tank is undersized so running at max revs for more than a few minutes would cause the engine to overheat. However we do boat on the Soar and Trent when they are in amber and we know from experience how to manage the engine to avoid overheating. For example on leaving Beeston heading upstream we keep the revs low enough to make fair progress with the knowledge that as you approach Cranfleet the river narrows and is shallow and you have to increase the revs to counter the increase in current. Because we manage the revs we do not get overheating. It is really about getting to know the charecteristics of your boats power train.

 

I used to have the same issue on my boat but just fitted a second skin tank. Problem solved.

[GUMPY]

Many years ago In had a 33ft narrow boat with a 10hp 2 cylinder  Nanni.

We left Diglis when there was a flood on the Severn just under 2ft up (BW wouldn't let you out if it was over 2ft)

Left Diglis lock backwards as there was a good chance if we gad come out forwards we couldn't have turned into the stream.

Eight hours later we arrived at Stourport to be greeted by a blaspheming lock keeper.

What the F are you doing on the river, Who the F let you out on the river ?

It was slow and the engine was running flat out to get us there but no other problems.

So 10hp can get you places

 

 

 

[PaulJ]

1 hour ago, Loddon said:

 

So 10hp can get you places

 

 

 

One of my favourite runs ever down the Nene on my way to Huntingdon was on a fairly hefty 67ft Barry Hawkins fitted with a 10hp Gardner 1L2. 

Was OK though I will admit I was a bit slow turning coming out of Ashton Lock into a breeze ,went too wide and then spent a while getting off the gravel bar there 😀

 

 

[ditchcrawler]

1 hour ago, PaulJ said:

One of my favourite runs ever down the Nene on my way to Huntingdon was on a fairly hefty 67ft Barry Hawkins fitted with a 10hp Gardner 1L2. 

Was OK though I will admit I was a bit slow turning coming out of Ashton Lock into a breeze ,went too wide and then spent a while getting off the gravel bar there 😀

 

 

Did it have a hydraulic drive 

[PaulJ]

2 minutes ago, ditchcrawler said:

Did it have a hydraulic drive 

PRM box with a strangely backwards push/pull lever!

Took me a while to get used to pushing it forwards to go into reverse and then even longer on the next boat to remember NOT to do it that way round 😀

[matty40s]

Was that the one ABNB took an age to sell?

 

 

We only have 18hp for our 70ft narrowboat, it has enjoyed the Severn, Wey, Thames, Nene, Soar(even in flood), Trent.

It even spent time running on 1 pot on the Soar(including a night time hairy downstream run in flood).

Edited May 16, 2023 by matty40s

[ditchcrawler]

39 minutes ago, PaulJ said:

PRM box with a strangely backwards push/pull lever!

Took me a while to get used to pushing it forwards to go into reverse and then even longer on the next boat to remember NOT to do it that way round 😀

OK I came back from Crick may years ago with Barry bringing a boat back with a hydraulic pump driving off the front of the engine,

[PaulJ]

5 minutes ago, matty40s said:

Was that the one ABNB took an age to sell?

Not sure on that one-hand start and no alternator would have put alot of people off (though did have a proper genset)

2 minutes ago, ditchcrawler said:

OK I came back from Crick may years ago with Barry bringing a boat back with a hydraulic pump driving off the front of the engine,

Was that Barry the singing boatmover- used to run hotel boats?