Articulated Rudder

[Horace42]

4 hours ago, Mike the Boilerman said:

 

 

Are we allowed to have meta discussions about politics (i.e. discussions about discussing politics)?

 

Or are they ruled out too? 

 

No, but give an inch and they take a mile.

[Sea Dog]

4 hours ago, Mike the Boilerman said:

Or are they ruled out too? 

At this point, I think we really ought to reiterate that we're ruling nothing out - unless that doesn't sit well on social media, in which case we may have to rule out ruling nothing out. I trust that's now perfectly clear?

[WotEver]

5 hours ago, Mike the Boilerman said:

May I propose that discussing quotes from Churchill be classed as 'political history' rather than politics? 

But following that with an opinion on said quotes is most certainly political. 

[Lionel Biden]

Hi everyone, I built a boat with an articulated rudder. My boat was launched July 2017. I'm quite happy with it, but admit I've never driven anyone else's boat so can't compare. If you go on YouTube and type Biden articulated rudder in search it will show you a short video of mine. Thanks Lionel 

[David Mack]

 

[IanD]

An articulated rudder built using flat plates is almost certainly less effective than a much simpler Schilling rudder as far as getting more sideways thrust (especially at large angles) is concerned -- rough order of merit is:

 

1. flat-plate rudder (conventional narrowboat)

2. articulated flat-plate rudder (as shown in video)

3. aerofoil-type fishtail rudder (Schilling)

4. articulated aerofoil-type rudder

 

The reason is that with flat plates the water flow behind the rudder breaks away turbulently at large angles and lift drops; the flat-plate articulated has the same problem, but there's more water deflection from the front face than a plain rudder. Thick aerofoil-type rudders keep the water flow on the rear face laminar and attached much longer, giving a lot more lift, and the Schilling fishtail restores the pressure as the water leaves the rudder which further increases lift at high angles.

 

They're not used much in ships because the drag in open water is a little bit higher, but Schilling rudders are a very good solution for inland waterways boats, especially on the canals where you sometimes need to push the rudder hard over.

 

The boat I'm having built will have one, it'll be interesting to see how much better it is than a flat-plate rudder... 😉

Edited March 13, 2022 by IanD

[ditchcrawler]

1 hour ago, IanD said:

 

 

They're not used much in ships because the drag in open water is a little bit higher, but Schilling rudders are a very good solution for inland waterways boats, especially on the canals where you sometimes need to push the rudder hard over.

 

The boat I'm having built will have one, it'll be interesting to see how much better it is than a flat-plate rudder... 😉

Didn't Daniel build one for his boat.

[IanD]

4 minutes ago, ditchcrawler said:

Didn't Daniel build one for his boat.

 

I believe so, and was pleased with the result.

 

I found a later Schilling patent from 1984 specifically aimed at getting better response at slow speeds and high rudder angles, so I'm giving that a try -- should be even better...

 

 

[David Mack]

Does that give actual dimensions you can use? Last time I looked there were lots of advocates for aerofoil rudders along with generic advice, but but little hard information on design parameters. I also saw comments that the various designs out there are all proprietary (as is the term "Schilling rudder") and that copying any of them, or even publishing the designs, would bring the lawyers down on you.

[IanD]

4 hours ago, David Mack said:

Does that give actual dimensions you can use? Last time I looked there were lots of advocates for aerofoil rudders along with generic advice, but but little hard information on design parameters. I also saw comments that the various designs out there are all proprietary (as is the term "Schilling rudder") and that copying any of them, or even publishing the designs, would bring the lawyers down on you.

 

Yes there are real dimensions in there if you read carefully 😉

 

A patent is valid for 20 years so that one expired in 2004. Patents are public domain, so anyone is free to publish or use the design information in it after it expires. If sombody has trademarked the name "Schilling rudder" then anyone offering to sell something publicly might get into trouble, but this is unlikely after such a long time -- also this was the last patent Schilling filed so anything is likely to have expired anyway.