Ruston Hornsby 2YD

[1stArthur]

Hi I’ve never had a Ruston Hornsby 2YD engine before, Does anyone know what size prop is recommended for this engine? 

[Alan de Enfield]

21 minutes ago, 1stArthur said:

Hi I’ve never had a Ruston Hornsby 2YD engine before, Does anyone know what size prop is recommended for this engine? 

 

 

It will depend on the size of your boat and how much space you have to swing a blade, and, the gearbox and gearbox ratio you have.

[1stArthur]

The boat is 57’ no info on the gearbox yet or space. I thought there may have been a recommended size . My Beta 43 has a recommended 12x18 prop . 

[Alan de Enfield]

19 minutes ago, 1stArthur said:

The boat is 57’ no info on the gearbox yet or space. I thought there may have been a recommended size . My Beta 43 has a recommended 12x18 prop . 

 

It doesn't matter what prop is specified if the height from your shaft to the underside of the counter can't accomodate it.

 

If you only have (say) 10" from the centre of your prop shaft to the underside of th counter there is no way that you could fit (say) a 22" propellor.

Big slow reving engines tend to have big props, not the egg-whisks that modern engines have)

 

For example my prop .....................

 

 

 

 

 

 

 

 

 

 

 

1 hour ago, 1stArthur said:

Hi I’ve never had a Ruston Hornsby 2YD engine before, Does anyone know what size prop is recommended for this engine? 

 

 

Just askin - why ?

 

Does it not have a prop, or are there problems with the existing prop ?

Edited June 21, 2023 by Alan de Enfield

[1stArthur]

Hi thanks for that . 
I understand the size thing but you can over prop if you have the space to fit it , too big and it will knacker your gearbox . So what I understand is engine gearbox = a certain size prop . As my Beta 43 does. I haven’t got the boat yet withe the said engine so I do appreciate your advice thank you .

[Alan de Enfield]

1 minute ago, 1stArthur said:

I understand the size thing but you can over prop if you have the space to fit it

 

Indeed you can, which is why everytthing is interlinked - (diameter, pitch, gearbox ratio and available space) it is not possible to always fit the engine manufacturers suggested size, and canal boats are very rarely fitted with the 'optimum size' anyway - using a prop to push you thru a soupy-watery mud is not what they were designed for.

[1stArthur]

Thank you 

my reason for concern is that I’m based on the K&A and we traverse the Thames every year so going up stream sometimes needs some power . So I’m trying to find out what this boat will do . I really need to go see for myself but I really appreciate your help thank you .

[IanD]

14 minutes ago, 1stArthur said:

Thank you 

my reason for concern is that I’m based on the K&A and we traverse the Thames every year so going up stream sometimes needs some power . So I’m trying to find out what this boat will do . I really need to go see for myself but I really appreciate your help thank you .

 

If you know the engine/gearbox details (power/rpm/ratio) you could do worse than seeing what the Vicprop calculator suggests as a starting point, and whether this will physically fit on your boat...

 

https://vicprop.com/displacement_size_new.php

 

(for all the Beta engines I looked at it suggests prop sizes pretty close to what Beta recommend, or maybe a bit smaller)

 

If the recommended size won't fit (they're usually about P/D=0.7 which is optimum) because the diameter is too big, then you can decrease diameter and increase pitch by twice the amount (e.g. diameter -10% pitch +20%) and get similar performance. It's preferable not to go oversquare (pitch>diameter) but you might have no choice if there's not enough space from prop shaft to skeg/uxter plate...

Edited June 21, 2023 by IanD

[BEngo]

You could Google for prop calc.  It will want you to input some things you don't yet know, but once you have it will give you a good starting point.

 

You say the Beta 43 has a recommended prop.  That can only be true for a specific gearbox ratio, and thdcsizecwill vary radically between, say, a 2:1 reduction and, say, a 3:1 reduction.  As an example take the Kelvin J2.  22 hp at 1000 rpm  It has a direct drive (1:1) gearbox and the factory  recommended prop is 19 x 13 in.  A Lister JP2M producing about 18 hp at 1200 rpm, so a similar power and speed,  with the common   2:1 reduction gearbox,  needs a prop which is much larger, something like 26 x18 in. If you take the Lister on a 3:1 box you will be at near 30 in diameter.

 

  All that said, the 2YD is a good narrow boat engine, and,  provided it is well installed, should be no problem power wise on the Thames.

 

I would be more interested in the cooling arrangements, and the size of any skin tanks.  Too many boats are built with undersized cooling tanks  so that river work causes overheating.

 

N

 

[IanD]

16 minutes ago, BEngo said:

You could Google for prop calc.  It will want you to input some things you don't yet know, but once you have it will give you a good starting point.

 

You say the Beta 43 has a recommended prop.  That can only be true for a specific gearbox ratio, and thdcsizecwill vary radically between, say, a 2:1 reduction and, say, a 3:1 reduction.  As an example take the Kelvin J2.  22 hp at 1000 rpm  It has a direct drive (1:1) gearbox and the factory  recommended prop is 19 x 13 in.  A Lister JP2M producing about 18 hp at 1200 rpm, so a similar power and speed,  with the common   2:1 reduction gearbox,  needs a prop which is much larger, something like 26 x18 in. If you take the Lister on a 3:1 box you will be at near 30 in diameter.

 

  All that said, the 2YD is a good narrow boat engine, and,  provided it is well installed, should be no problem power wise on the Thames.

 

I would be more interested in the cooling arrangements, and the size of any skin tanks.  Too many boats are built with undersized cooling tanks  so that river work causes overheating.

 

N

 

The Beta recommended prop (18" x 12" for Beta 43) is with the standard 2:1 gearbox. A 3:1 box would give a bigger prop with less noise and wash, but too big a diameter for most modern hulls, which is why this isn't common.

1 hour ago, 1stArthur said:

The boat is 57’ no info on the gearbox yet or space. I thought there may have been a recommended size . My Beta 43 has a recommended 12x18 prop . 

The data I found for the 2YD says 38hp at 2200rpm.

 

Assuming the gearbox is 2:1 (most likely), Vicprop suggests 19.5" x 13.3" for a 3-blade, so 19" x 14" would be a good starting point.

Edited June 21, 2023 by IanD

[1stArthur]

That sounds good thank you . I need to get to the boat and maybe measure the prop and existing space if any through the weed hatch , all could be good, what i don’t want to do is over prop and cause damage. That’s why I thought I would ask and I’ve not been disappointed thank you very much . 

[IanD]

56 minutes ago, 1stArthur said:

That sounds good thank you . I need to get to the boat and maybe measure the prop and existing space if any through the weed hatch , all could be good, what i don’t want to do is over prop and cause damage. That’s why I thought I would ask and I’ve not been disappointed thank you very much . 

Over-propping is unlikely to cause damage, what it will mean is you can't get the engine up to full speed/power on a river, and the boat might be too fast at tickover and annoy some badly moored boaters... 😉

 

OTOH it lowers rpm and noise and vibration when you're cruising along, so some boaters prefer a degree of overpropping to a prop matched to full power/rpm.

 

Let's see if anyone with the same engine and gearbox can give more advice... 🙂

[BoatinglifeupNorth]

Edit

Edited June 22, 2023 by BoatinglifeupNorth

[churchward]

23 hours ago, IanD said:

Over-propping is unlikely to cause damage, what it will mean is you can't get the engine up to full speed/power on a river, and the boat might be too fast at tickover and annoy some badly moored boaters... 😉

 

OTOH it lowers rpm and noise and vibration when you're cruising along, so some boaters prefer a degree of overpropping to a prop matched to full power/rpm.

 

Let's see if anyone with the same engine and gearbox can give more advice... 🙂

Yes, I think it does help with noise, etc.  Our 50ft NB has a Beta BV1505 (older B38) and a 2.6:1 box plus a 18X13 prop (I have seen the punched marks).  I don't think it can make max rpm, especially in reverse which is 1.95:1 but we truck along with it, and was fine on the River Severn when we went to Gloucester and back this year.  I think the prop is recommended to be 17X10.

[1stArthur]

4 minutes ago, churchward said:

Yes, I think it does help with noise, etc.  Our 50ft NB has a Beta BV1505 (older B38) and a 2.6:1 box plus a 18X13 prop (I have seen the punched marks).  I don't think it can make max rpm, especially in reverse which is 1.95:1 but we truck along with it, and was fine on the River Severn when we went to Gloucester and back this year.  I think the prop is recommended to be 17X10.

Thank you for the info much appreciated 

Im looking for a project hopefully a tug with a good engine so the more information I can get the better. The boat I have is a 60’ coalcraft with a Beta 43 and an 18x12 prop that seems good on the Thames .

[Mike Hurley]

https://narrowboats.apolloduck.com/boat/charles-cox-66-traditional-for-sale/734835

 

Not a project but nice engine.

[john.k]

I have a NOS 3YC that I considered for a boat......but a decided minus feature is the exposure of the fuel injection system.............the engines are designed for the back of a crane where the doors can be closed to shield the exposed racks and plungers from the elements.

[T.Dreme]

On 22/06/2023 at 19:24, 1stArthur said:

Thank you for the info much appreciated 

Im looking for a project hopefully a tug with a good engine so the more information I can get the better. The boat I have is a 60’ coalcraft with a Beta 43 and an 18x12 prop that seems good on the Thames .

Did you resolve your prop issue?  Just seen this conversation.  
 

I have a 2YD water cooled with the governor springs giving 500 to 1300 rpm.  My prop is a Crowther 25” x 17” which gives plenty of push on the rivers.  They calculated it as a 27” but compressed it somehow to 25”. You can’t really compare it to a Beta due to the revs.  I very rarely get mine up to 1300rpm except for a blast to clear her tubes. 

[Up-Side-Down]

A couple of things to throw into the mix:

 

i) I was recommended by Keith, of Crowther props, to leave a space of at least 10% of prop diameter between the underside of the uxter plate and the prop tip.

ii) When Keith retired his goto recommendation was https://clementsengineering.co.uk. Vicprop is a good starting point but no substitute for experience in interpreting a program's output.

iii) If all else fails, consider a four-bladed prop.