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Are Narrowboats getting uglier?


PD1964

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1 minute ago, noddyboater said:

I think you're doing the right thing by modifying the standard design at this stage.

I don't know why exactly but TT/JW rudders just don't seem to work efficiently when manoeuvring at slow speed. 

It might be the amount of balance designed in, you can steer with one finger quite easily,  or just the basic spacing of prop/rudder blade.

You certainly don't get much "thrutch" coming out where you need it.

 

 

Thanks, it's nice to see that some people agree that it's worth trying out things instead of always doing it "the old way" -- not that the old ways are always wrong and the new way is always right, but without change nothing ever improves. But this does need somebody to stick their neck out (and their hands into their pockets) to try it, and I'm happy to be the one to do this 🙂

 

I've had long talks with Ricky about various aspects of boat design, and we've rejected a lot of my ideas that won't work for one reason or another, but kept some in -- the rudder is one, better generator sound/vibration isolation is another. If they work then they can be offered to new boat buyers as an (extra cost) option if they want a "better" boat, which Ricky is keen on -- hence all the work Finesse have done on the propulsion system. If people don't want them then they don't have to have them, their choice.

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17 minutes ago, noddyboater said:

It might be the amount of balance designed in, you can steer with one finger quite easily,  or just the basic spacing of prop/rudder blade.

You certainly don't get much "thrutch" coming out where you need it.

 


  What is the correct position for the prop in relation to the rudder?

 I would say there may be a big difference throughout the network with TT/JW boats, as most of the time they just provide the hulls to the various builders, who use their own engine/prop set up guy. 

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3 minutes ago, PD1964 said:


  What is the correct position for the prop in relation to the rudder?

 I would say there may be a big difference throughout the network with TT/JW boats, as most of the time they just provide the hulls to the various builders, who use their own engine/prop set up guy. 

 

From various marine engineering sites, the minimum spacing from hull V to prop (nearest point on blades) is 0.27D for a 3-blade, 0.25D for a 4-blade -- so about 5" for a typical 18x12" 3-blade. Even more is better, especially if the hull V doesn't come to a sharp point. If the swim is too short (which is is on many boats) then water entry to the prop is worse still so more spacing is better.

 

Optimum spacing from blades to rudder for maximum rudder effectiveness is quite small, around 0.1D or 2" -- but this may be too close to allow big debris through the gap, 0.15D/3" is better. With small spacing a 3-blade prop can cause rudder vibration as the blades pass it, a 4-blade is better for this especially with a tiller rather than a wheel (narrowboats).

 

From the photos I've seen, most narrowboats have the prop too close to the hull and too far from the rudder. I'm talking to Ricky about how far it (with 4 blades...) can be moved back without too much prop shaft becoming exposed or needing a longer non-standard stern tube...

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I’m entirely intrigued by this Schilling rudder business, very much hoping it works well for you. Would you not have to try the boat with a standard rudder first though to know if it made much/lots of difference to the handling when fitted?

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Just now, Hudds Lad said:

I’m entirely intrigued by this Schilling rudder business, very much hoping it works well for you. Would you not have to try the boat with a standard rudder first though to know if it made much/lots of difference to the handling when fitted?

In theory yes -- but then Finesse have other similar boats being built with a standard rudder, we might even be able to directly compare the two.

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16 minutes ago, PD1964 said:


  What is the correct position for the prop in relation to the rudder?

 I would say there may be a big difference throughout the network with TT/JW boats, as most of the time they just provide the hulls to the various builders, who use their own engine/prop set up guy. 

I don't know what the correct position is,  but I do know that when I pile the revs on (all 900 of them) and steer around a tight bend on my boat it takes a lot of muscle to keep the tiller over, or you put your back into it instead. 

It can be done one handed on a TT hull, whether running a large prop or not.

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16 minutes ago, noddyboater said:

I don't know what the correct position is,  but I do know that when I pile the revs on (all 900 of them) and steer around a tight bend on my boat it takes a lot of muscle to keep the tiller over, or you put your back into it instead. 

It can be done one handed on a TT hull, whether running a large prop or not.

That's to do with how much balance the rudder has -- too little and it's heavy, too much and it's either too light or at large angles can even flop over to one side with tiller steering.

 

Many narrowboats have too little balance, so the rudder is heavy as you describe. For a flat-plate rudder steered by a tiller the optimum is somewhere around 20% balance, so with 4x as much rudder behind the stock (80%) as in front of it (see TT photo) -- with wheel steering maybe 25% minimises the load on the steering gear, so ships use this.

 

With a Schilling rudder the centre of pressure is further back due to the aerofoil-type section, so about 25% balance is optimum for tiller steering (30% for wheel steering).

 

Most narrowboat builders are pretty much unaware of all this (including spacings to hull/skeg/rudder), they just do what they've always done or everyone else does -- in spite of the fact that this kind of stuff is well-known in the "proper" marine engineering field (ship design) and there's no reason to ignore it.... 😞

flat rudder.jpg

Edited by IanD
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1 minute ago, IanD said:

That's to do with how much balance the rudder has -- too little and it's heavy, too much and it's either too light or at large angles can even flop over to one side with tiller steering.

 

Many narrowboats have too little balance, so the rudder is heavy as you describe. For a flat-plate rudder steered by a tiller the optimum is somewhere around 20% balance, so with 4x as much rudder behind the stock (80%) as in front of it -- with wheel steering maybe 25% minimises the load on the steering gear, so ships use this.

 

With a Schilling rudder the centre of pressure is further back due to the aerofoil-type section, so about 25% balance is optimum for tiller steering (30% for wheel steering).

 

Most narrowboat builders are pretty much unaware of all this (including spacings to hull/skeg/rudder), they just do what they've always done or everyone else does -- in spite of the fact that this kind of stuff is well-known in the "proper" marine engineering field (ship design) and there's no reason to ignore it.... 😞

Too much balance isn't good,  you lose the feedback- a bit like modern cars with overly light electric steering. 

Boat builders like Sarah who posted earlier have a distinct advantage with such things,  they look at the hull of a nearby working boat.

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1 minute ago, noddyboater said:

Too much balance isn't good,  you lose the feedback- a bit like modern cars with overly light electric steering. 

Boat builders like Sarah who posted earlier have a distinct advantage with such things,  they look at the hull of a nearby working boat.

 

You also have to consider that we are navigating a muddy ditch... 

 

Not that I am saying I'm not for progress at all, I'm all for it. I just favour tried, tested and good quality. 

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There has long been discussion on various trawler forums about Schilling rudders and doing it on the cheap. 

The consensus is that if you put top and bottom plates on the ruder and a bit of angle on the trailing edge of the rudder you get much of the benefits with little of the cost. It's something I have been toying with for years but have never got round to as with  my last two boats I have been able to spin them both in their own length (without a bow thruster) so couldn't see the point of spending the dosh.

Here is one such

https://www.trawlerforum.com/forums/showpost.php?p=39665&postcount=7

 

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6 minutes ago, IanD said:

That's to do with how much balance the rudder has -- too little and it's heavy, too much and it's either too light or at large angles can even flop over to one side with tiller steering.

 

Many narrowboats have too little balance, so the rudder is heavy as you describe. For a flat-plate rudder steered by a tiller the optimum is somewhere around 20% balance, so with 4x as much rudder behind the stock (80%) as in front of it -- with wheel steering maybe 25% minimises the load on the steering gear, so ships use this.

 

With a Schilling rudder the centre of pressure is further back due to the aerofoil-type section, so about 25% balance is optimum for tiller steering (30% for wheel steering).

 

Most narrowboat builders are pretty much unaware of all this (including spacings to hull/skeg/rudder), they just do what they've always done or everyone else does -- in spite of the fact that this kind of stuff is well-known in the "proper" marine engineering field (ship design) and there's no reason to ignore it.... 😞

 But as I’ve said before do they ignore these things because there is minimum benefits in handling/propulsion on a shallow canal, compared to sea going vessels where it’s more beneficial?

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1 hour ago, noddyboater said:

Too much balance isn't good,  you lose the feedback- a bit like modern cars with overly light electric steering. 

Boat builders like Sarah who posted earlier have a distinct advantage with such things,  they look at the hull of a nearby working boat.

 

As well as having no "feel", the other problem with too much balance (and tiller steering) is that at large angles the centre of pressure moves and you can end up having to pull the tiller towards the boat centreline to stop it flopping right over, the force on the tiller changes from positive to negative. This doesn't matter with wheel steering, which is why ships use more balance.

 

All this also depends on other things like the flow of water past the hull and prop and rudder size; some working boats were designed to be nicely balanced, others were more thrown together at the lowest cost and were nasty to steer.

 

An exact copy of a "good" working boat *in all respects* (hull, prop, rudder, spacings, swim) will also be good, but not just if you pick some features and not others -- it's like baking a cake, different well-balanced recipes work but changing one ingredient can lead to disaster... 😞

1 hour ago, PD1964 said:

 But as I’ve said before do they ignore these things because there is minimum benefits in handling/propulsion on a shallow canal, compared to sea going vessels where it’s more beneficial?

If that's what you think, don't do it. I disagree. The proof of the pudding will be next year... 😉

Edited by IanD
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2 minutes ago, PD1964 said:

 But as I’ve said before do they ignore these things because there is minimum benefits in handling/propulsion on a shallow canal, compared to sea going vessels where it’s more beneficial?

What happens if it does not work. You have a fairly expensive job as the boat could have to be taken out of the water by which time it could be miles from the builder, and then possibly modified. Are you prepared to take the risk

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31 minutes ago, Loddon said:

There has long been discussion on various trawler forums about Schilling rudders and doing it on the cheap. 

The consensus is that if you put top and bottom plates on the ruder and a bit of angle on the trailing edge of the rudder you get much of the benefits with little of the cost. It's something I have been toying with for years but have never got round to as with  my last two boats I have been able to spin them both in their own length (without a bow thruster) so couldn't see the point of spending the dosh.

Here is one such

https://www.trawlerforum.com/forums/showpost.php?p=39665&postcount=7

 

And there are other detailed analyses of rudder design -- academic and industrial -- including different profiles which show exactly the opposite, the blade shape *does* make a big difference.

 

it's all a matter of how much bother you want to take (and pay for); dead simple and cheap (flat plate), better but still cheap to build (what Loddon described), or better still at but at higher cost (what I'm planning).

 

All are valid choices depending on your wants and needs, just like buying a cheap old car or a decent one-owner car or a new one... 😉

24 minutes ago, Tonka said:

What happens if it does not work. You have a fairly expensive job as the boat could have to be taken out of the water by which time it could be miles from the builder, and then possibly modified. Are you prepared to take the risk

 

It's not going to "not work", it's a rudder. The question is whether it gives a big improvement in steering, a small one, none, or makes things worse.

 

Given all the reports about Schilling rudders from people who have actually tried them as opposed to being keyboard critics, my money (literally!) is on a big improvement -- we'll see... 😉

 

I'm willing to take the risk, I've taken far bigger risks than this with new ideas many times both personally and at work, and my experience is that if these are carefully analysed -- including recognising possible disadvantages -- they almost always work. Maybe that's why I hold more than 60 patents... 😉

Edited by IanD
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19 minutes ago, IanD said:

And there are other detailed analyses of rudder design -- academic and industrial -- including different profiles which show exactly the opposite, the blade shape *does* make a big difference.

 

it's all a matter of how much bother you want to take (and pay for) dead simple and cheap (flat plate), better but still cheap to build (what Loddon described), or better still at but at higher cost (what I'm planning).

 

All are valid choices depending on your wants and needs, just like buying a cheap old car or a decent one-owner car or a new one... 😉

 

It's not going to "not work", it's a rudder. The question is whether is gives a big improvement in steering, a small one, none, or makes things worse.

 

Given all the reports about Schilling rudders from people who have actually tried them as opposed to being keyboard critics, my money (literally!) is on a big improvement -- we'll see... 😉

 

I'm willing to take the risk, I've taken far bigger risks than this with new ideas many times both personally and at work, and my experience is that if these are carefully analysed -- including recognising possible disadvantages -- they almost always work. Maybe that's why I hold more than 60 patents... 😉

You must be Professor Pat Pending. He had his name on loads of stuff 

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12 minutes ago, Tonka said:

You must be Professor Pat Pending. He had his name on loads of stuff 

Yeah, he's a mate. Terrible hairdo though... 😉

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2 hours ago, PD1964 said:

 I’ve never insulted you, I’ve just questioned the need for such a rudder on the canals, yours and maybe  a couple of others will be the only narrowboats with then, so that tells me there’s not a massive advantage in having one, or they would be industry standard fit.

I would suggest that 90% of people who buy a new boat don't have a clue what's under the water and are more worried where the Microwave will be situated and lots don't even consider how they will power the microwave when they get it.

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11 minutes ago, ditchcrawler said:

I would suggest that 90% of people who buy a new boat don't have a clue what's under the water and are more worried where the Microwave will be situated and lots don't even consider how they will power the microwave when they get it.

Absolutely true, which is why a lot of builders (and shows like Crick) focus on snazzy fixtures and fittings, because that's what most customers are interested in.

 

Only a few engineering weirdos like me actually *care* about things like hull/prop/rudder/engine/electrics design, proper noise and vibration isolation, and providing robust power to the microwave and everything else.

 

OTOH I also spent a*lot* of time working out how to fit everything into the boat and make it all usable, including things like the kitchen design -- just like at home, ergonomics *do* matter, and I'd rather have somewhere which is nice to live in rather than a boat where you're perpetually swearing at various ill-thought-out things that are difficult to get to and use, like many boats... 🙂

Edited by IanD
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5 minutes ago, ditchcrawler said:

I would suggest that 90% of people who buy a new boat don't have a clue what's under the water and are more worried where the Microwave will be situated and lots don't even consider how they will power the microwave when they get it.

That’s it, then there's people who have deep pockets that want to try and reinvent the wheel. In the real world of canal boating will these people have an impact on Narrowboat design? I doubt it.

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6 minutes ago, PD1964 said:

That’s it, then there's people who have deep pockets that want to try and reinvent the wheel. In the real world of canal boating will these people have an impact on Narrowboat design? I doubt it.

I want to try and reinvent *my* wheel. What you (and the mass market) do with your stone-age wheel is entirely up to you... 😉

 

LFP batteries (and EVs...) used to have exactly the same response -- they're new and untried, too expensive, nothing wrong with my good old LA batteries, why do you want all that power anyway? Now the market is gradually shifting over as more people realise they have real advantages -- but nobody is forcing anyone to switch, carry on with cheap rubbish lead-acids (and ICE) if that floats your boat 😉

Edited by IanD
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1 minute ago, PD1964 said:

 . In the real world of canal boating will these people have an impact on Narrowboat design? I doubt it.

And does that matter?

 

I have a hydraulic drive and a hydraulic bowthruster, I don't care if there isn't another single boat out there with the same. I have an engine in an engine room, how many of them are being built today/

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2 minutes ago, IanD said:

Absolutely true, which is why a lot of builders (and shows like Crick) focus on snazzy fixtures and fittings, because that's what most customers are interested in.

 

Only a few engineering weirdos like me actually *care* about things like hull/prop/rudder/engine design, proper silencing and vibration isolation, and providing robust power to the microwave and everything else.

 

OTOH I also spent a*lot* of time working out how to fit everything into the boat and make it all usable, including things like the kitchen design -- just like at home, ergonomics *do* matter, and I'd rather have somewhere which is nice to live in rather than a boat where you're perpetually swearing at various ill-thought-out things that are difficult to get to and use, like many of the hire boats... 🙂

Please don’t take this the wrong way, it’s a serious suggestion. Why don’t you start a Thread on the boat building section, highlighting your boat build and your ideas, instead of putting them on various threads(ugly boat, electric boat) It would be interesting to see your boats progress and your ideas being developed and tested👍👍

3 minutes ago, ditchcrawler said:

And does that matter?

 

I have a hydraulic drive and a hydraulic bowthruster, I don't care if there isn't another single boat out there with the same. I have an engine in an engine room, how many of them are being built today/

Not many, as people who want boats today don’t want the wasted space, their boat smelling of diesel fumes and are fitting electric motors.

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18 minutes ago, PD1964 said:

Please don’t take this the wrong way, it’s a serious suggestion. Why don’t you start a Thread on the boat building section, highlighting your boat build and your ideas, instead of putting them on various threads(ugly boat, electric boat) It would be interesting to see your boats progress and your ideas being developed and tested👍👍

 

Partly because I don't want to brag, partly because even though the original ideas might have been mine how to make the end result work in practice has been worked out together with Ricky, and some of it is a combination of ideas from both of us. It's why I'm only talking about information that's publicly available -- for example I know a lot more about the boat's custom electric drive system than most, but wouldn't give this away.

 

The rudder is entirely my idea so I'm happy to talk about that. So is the generator NVH reduction measures, but then Ricky agreed to build it and plans to test it compared to the conventional solution so he can offer it as an option -- which means it would be unfair to give all the details away on how it's built to his competitors. The basic idea, yes, but no details or photos.

 

So it's tricky -- one the one hand it would be nice to show everything in detail, on the other hand I don't want to p*ss off the guy who listened and helped me turn all the (workable) ideas into reality while gently pointing out why some ideas wouldn't work in practice, and is putting a lot of effort into building what I hope will be a *very* nice boat which does exactly what *I* want it to do... 🙂

 

If other people don't like the end result because it's not their (expensive, using modern technology) cup of tea, that's their business -- I'm not forcing them to buy one...

Edited by IanD
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10 minutes ago, IanD said:

 

Partly because I don't want to brag, partly because even though the original ideas might have been mine how to make the end result work in practice has been worked out together with Ricky, and some of it is a combination of ideas from both of us. It's why I'm only talking about information that's publicly available -- for example I know a lot more about the boat's custom electric drive system than most, but wouldn't give this away.

 

The rudder is entirely my idea so I'm happy to talk about that. So is the generator NVH reduction measures, but then Ricky agreed to build it and plans to test it compared to the conventional solution so he can offer it as an option -- which means it would be unfair to give all the details away on how it's built to his competitors. The basic idea, yes, but no details or photos.

 

So it's tricky -- one the one hand it would be nice to show everything in detail, on the other hand I don't want to p*ss off the guy who listened and helped me turn all the (workable) ideas into reality while gently pointing out why some ideas wouldn't work in practice, and is putting a lot of effort into building what I hope will be a *very* nice boat which does exactly what *I* want it to do... 🙂

 

If other people don't like the end result because it's not their (expensive, using modern technology) cup of tea, that's their business -- I'm not forcing them to buy one...

 Please do it, you may think I’m not interested in reinventing the wheel, but I’m always interested in ideas that may work or not. Also remember that Ricky and any his crew have never owned a Narrowboat but are at the forefront of electrical propulsion and are producing ground braking boats. As shown at this years Crick show. So please just do it.

A310D28A-C9A2-4495-B0E8-219AAD3C4C91.jpeg.f794b3222ec6d71d3dae8e0e7480d44a.jpeg

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5 minutes ago, PD1964 said:

 Please do it, you may think I’m not interested in reinventing the wheel, but I’m always interested in ideas that may work or not. Also remember that Ricky and any his crew have never owned a Narrowboat but are at the forefront of electrical propulsion and are producing ground braking boats. As shown at this years Crick show. So please just do it.

A310D28A-C9A2-4495-B0E8-219AAD3C4C91.jpeg.f794b3222ec6d71d3dae8e0e7480d44a.jpeg

 

And they are also absolutely lovely guys that really care about their product. 

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