Throttle Control

[Workhorse]

A bit of advice please, I have, as many others have, a TeleFlex MV2 Morse Control (Throttle Control) which works fine, But how much free movement should there be from what I would call the 12.00 o'clock position when the engine is ticking over to moving the control handle forward to increase the engine rpm. Mine seems to have what I feel is a little too much, but I could be wrong. In fact, mine moves from the 12.00 o'clock position to around the 2.00 o'clock position before the engine picks up.

Is this correct, and if not, can it be adjusted?

 

The engine is a Beta 43HP, and the maximum engine speed I can achieve on the rev counter is 2000 rpm.

[Tony Brooks]

A bit of advice please, I have, as many others have, a TeleFlex MV2 Morse Control (Throttle Control) which works fine, But how much free movement should there be from what I would call the 12.00 o'clock position when the engine is ticking over to moving the control handle forward to increase the engine rpm. Mine seems to have what I feel is a little too much, but I could be wrong. In fact, mine moves from the 12.00 o'clock position to around the 2.00 o'clock position before the engine picks up.

Is this correct, and if not, can it be adjusted?

 

The engine is a Beta 43HP, and the maximum engine speed I can achieve on the rev counter is 2000 rpm.

 

 

Sounds about right to me.

 

Any single lever control must have lost movement on the throttle so you do not rev up before the gear is engaged - otherwise it tends to clonk into gear (more than usual).

 

 

I think this control uses a spring loaded anchor for the throttle cable. To adjust it get to the back of the control and watch the levers as someone puts it in gear. You should see the gear lever move, but the throttle lever, whilst moving, pushes/pulls its anchor until the gear is fully engaged.

 

adjust the length of the throttle cable so it slips into the hole in the control lever in the SLOW AHEAD/ASTERN position.

 

You may have wear in the control that gives a bit more movement, but as long as the boat can be controlled well I think it is fine.

 

The maximum speed may well be down to prop size. If you slowly move the lever and the revs keep rising until you get to about the 5 0'clock position, then it is probably cable adjustment, but I bet the revs rise and then stop rising even though you can move the lever more - thats prop, but again if the boat performs as you want it to put your wallet away and enjoy it.

 

 

 

Tony Brooks

[NB Willawaw]

Sorry cross-posted.

Edited May 5, 2007 by NB Willawaw

[Guest]

A bit of advice please, I have, as many others have, a TeleFlex MV2 Morse Control (Throttle Control) which works fine, But how much free movement should there be from what I would call the 12.00 o'clock position when the engine is ticking over to moving the control handle forward to increase the engine rpm. Mine seems to have what I feel is a little too much, but I could be wrong. In fact, mine moves from the 12.00 o'clock position to around the 2.00 o'clock position before the engine picks up.

Is this correct, and if not, can it be adjusted?

 

The engine is a Beta 43HP, and the maximum engine speed I can achieve on the rev counter is 2000 rpm.

I only ever see 2200 on our Vetus. I doubt the accuracy of the tacho myself, cause the boat fair knocks along (in NB terms) at full throttle. Could be slightly over propped, but as the boat behaves well I don't bother about it now.

[Tony Brooks]

I only ever see 2200 on our Vetus. I doubt the accuracy of the tacho myself, cause the boat fair knocks along (in NB terms) at full throttle. Could be slightly over propped, but as the boat behaves well I don't bother about it now.

 

 

Probably propped for maximum torque (which occurs at far lower speed that the quoted maximum) and will therefor give you the optimum fuel consumption. Likewise my Bukh only manages a bit over 2000, but has a maximum quoted speed of 3600. It it goes all right do not mess with it, says I.

 

 

Tony Brooks

[Timleech]

Probably propped for maximum torque (which occurs at far lower speed that the quoted maximum) and will therefor give you the optimum fuel consumption. Likewise my Bukh only manages a bit over 2000, but has a maximum quoted speed of 3600. It it goes all right do not mess with it, says I.

Tony Brooks

 

Also the bigger prop will be more efficient, especially at starting & stopping. The only thing you lose is the max power available from the engine, but do you really need it?

 

Tim

[Tony Brooks]

Also the bigger prop will be more efficient, especially at starting & stopping. The only thing you lose is the max power available from the engine, but do you really need it?

 

Tim

 

 

Especially when you realize that most (if not all) modern engines get their power from lots of revs and low torque, rather than lots of torque and low revs which I am sure would be better suited to a narrowboat or any other displacement craft.

 

Tony Brooks

[Keeping Up]

Especially when you realize that most (if not all) modern engines get their power from lots of revs and low torque, rather than lots of torque and low revs which I am sure would be better suited to a narrowboat or any other displacement craft.

 

Tony Brooks

Surely most boat diesels, whether ancient or modern, have a relatively flat torque curve over most of their working range, so that if they are geared down to the same prop-shaft revolutions it makes no difference how the engine gets its power.

 

Allan (with a 3:1 gearbox for lots of nice torque)

[Guest]

Probably propped for maximum torque (which occurs at far lower speed that the quoted maximum) and will therefor give you the optimum fuel consumption. Likewise my Bukh only manages a bit over 2000, but has a maximum quoted speed of 3600. It it goes all right do not mess with it, says I.

Tony Brooks

Thanks for that info, makes sense. Certainly our boat can stop in a very short distance which kind of backs up the torque idea. I certainly wont be changing anyhting.

[Tony Brooks]

Surely most boat diesels, whether ancient or modern, have a relatively flat torque curve over most of their working range, so that if they are geared down to the same prop-shaft revolutions it makes no difference how the engine gets its power.

 

Allan (with a 3:1 gearbox for lots of nice torque)

 

 

This is correct as far as it goes except I do not think the curves I have seen can be described as flat.

 

My engine returns 85 Nm at 1000 rpm, peaks at 90 Nm at about 2000 rpm and the falls off to 70 Nm at 3600 rpm. That is a falling torque for well over half the rev range

 

The fact that the torque peaks indicates that the fuel is being used most efficiently at that speed, so one would ideally use that as the cruising speed, however this would usu sally make a canal boat go too fast so a compromise is reached. This is why I think it is vital to get an inland specialist to specify your prop so they use their experience to get you the optimum performance.

 

The other thing is that as you put larger reduction ratios onto today's engine you often find the DAR (something to do with blade area) is less than ideal unless you go for a four blade or special three blade prop. This is supposing a typical narrow boat can effectively swing a large prop. I suspect 16 to 18 inch dia. is about as large as a tropical cruising boat can manage.

 

Tony Brooks

[Timleech]

This is correct as far as it goes except I do not think the curves I have seen can be described as flat.

 

My engine returns 85 Nm at 1000 rpm, peaks at 90 Nm at about 2000 rpm and the falls off to 70 Nm at 3600 rpm. That is a falling torque for well over half the rev range

 

The fact that the torque peaks indicates that the fuel is being used most efficiently at that speed, so one would ideally use that as the cruising speed, however this would usu sally make a canal boat go too fast so a compromise is reached. This is why I think it is vital to get an inland specialist to specify your prop so they use their experience to get you the optimum performance.

 

The other thing is that as you put larger reduction ratios onto today's engine you often find the DAR (something to do with blade area) is less than ideal unless you go for a four blade or special three blade prop. This is supposing a typical narrow boat can effectively swing a large prop. I suspect 16 to 18 inch dia. is about as large as a tropical cruising boat can manage.

 

Tony Brooks

 

Tropical cruising boats? wishing you were in the Caribbean instead of the English canals?

I don't understand that bit about Blade Area Ratio, Tony, until the limit of prop size is reached. After that yes it can be an issue, though I reckon the majority of modern boats could accomodate a substantially bigger prop than they are fitted with (I see a lot of them out of the water), but builders are happy to perpetuate the myth that you need 40+ bhp for a typical 57' narrow boat. It's certainly handy to have that power available when all you have to transfer it to the water is a little daisy.

It doesn't matter, AIUI, whether it's today's engine, yesterdays or one from 50 years ago. What matters is the horsepower and rpm. Or torque and rpm if you prefer, as hp = torque x rpm. If you gear an engine giving 20 hp at 2000 rpm down by 4:1, the result is the same as for an older engine giving 20hp at 500 rpm direct drive (think Bolinder semi-diesel). The propellor won't know the difference. (THe modern engine probably won't last as long as the Bolinder, but that's another issue).

Torque at lower speeds than max is largely irrelevant because the torque required by the prop goes up with rpm far more sharply (square law) than any engine torque/speed curve goes up or down.

 

Tim

[Tony Brooks]

Tropical cruising boats? wishing you were in the Caribbean instead of the English canals?

I don't understand that bit about Blade Area Ratio, Tony, until the limit of prop size is reached. After that yes it can be an issue, though I reckon the majority of modern boats could accomodate a substantially bigger prop than they are fitted with (I see a lot of them out of the water), but builders are happy to perpetuate the myth that you need 40+ bhp for a typical 57' narrow boat. It's certainly handy to have that power available when all you have to transfer it to the water is a little daisy.

It doesn't matter, AIUI, whether it's today's engine, yesterdays or one from 50 years ago. What matters is the horsepower and rpm. Or torque and rpm if you prefer, as hp = torque x rpm. If you gear an engine giving 20 hp at 2000 rpm down by 4:1, the result is the same as for an older engine giving 20hp at 500 rpm direct drive (think Bolinder semi-diesel). The propellor won't know the difference. (THe modern engine probably won't last as long as the Bolinder, but that's another issue).

Torque at lower speeds than max is largely irrelevant because the torque required by the prop goes up with rpm far more sharply (square law) than any engine torque/speed curve goes up or down.

 

Tim

 

The DAR thing.

 

Over time I have tried a number of on-line "prop calc" programs and the ones that will actually recognize narrow boat data inputs as valid often come up with messages such as the DAR is not ideal. this is why I say ask people experienced in inland prop calculations. The DAR thing tends to be confirmed by a number of people (one at least from this forum I think) who have found special props from Crowthers to offer enhanced performance. This seems to be more common with larger reduction ratios (as I would expect because of the increase in available torque).

 

What Tim says about the Bolinder comparison is of course correct, except it takes no account of the diameter of prop the boats fitted with such engines can physically swing. From looking around I get the distinct impression that an old working boat has a greater draft and also a longer sternpost than modern boats. The prop "knows" about the torque it is being supplied if that torque is high enough to cause the prop to be inefficient.

 

Tony Brooks

[DHutch]

I certainly agree that most narrow boats would benifit from a larger prop.

- And that you can then upto-a-point set any engine up to work as well as any other using the right gearbox ratio and pitch of propellor. And if you have a pitchy prop, you will also benifit from a higher DAR.

 

As we have a very slow running engine and no gearbox, with have a very large pitch propellor to compensate.

- And to get that work, and not be *stupidly* over square, it also has to be fairly large diameter. Around with the whole boat is designed. And its also fairly high DAR.

 

As such, with have a 58ft narrow boat that wieght as much as some widebeams, and a pleasing acceleration due to the large diameter.

- but we cant turn for toffee, because nowone though to design room for a equally scalled up rudder.

 

 

Daniel

[Tony Brooks]

I certainly agree that most narrow boats would benifit from a larger prop.

- And that you can then upto-a-point set any engine up to work as well as any other using the right gearbox ratio and pitch of propellor. And if you have a pitchy prop, you will also benifit from a higher DAR.

 

As we have a very slow running engine and no gearbox, with have a very large pitch propellor to compensate.

- And to get that work, and not be *stupidly* over square, it also has to be fairly large diameter. Around with the whole boat is designed. And its also fairly high DAR.

 

As such, with have a 58ft narrow boat that wieght as much as some widebeams, and a pleasing acceleration due to the large diameter.

- but we cant turn for toffee, because nowone though to design room for a equally scalled up rudder.

Daniel

 

 

Ah - but arn't you the only one here with maximum torque at zero revs - possibly a fairly ideal situation for acceleration.

 

 

Tony Brooks

[DHutch]

Ah - but arn't you the only one here with maximum torque at zero revs - possibly a fairly ideal situation for acceleration.

Tony Brooks

Yeah, well that does also help...

- Its good though, with a 20ihp engine and a 22ton boat, we can out accellerate most of 45,000hp crowd.

 

 

Daniel