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Rudder Load, boat turns right

Graham and Jo
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Graham and JoDonate to Canal World

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10 minutes ago, Mike the Boilerman said:

 

I too find people conflate poor tiller alignment with tiller bias to one side. T

Graham, can you remember how exactly your rudder was bent before you had it straightened

It had been nudged against a wharf in reverse and it was bent towards the right side looking forwards. It apeared to be bent slightly downwards at the top too. So it was missalgned with the tiller but the boat still had a reasonable tiller weight.

Cheers Grahan

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Graham and Jo Proficient

Graham and JoDonate to Canal World

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After following some of the recommendations I ended up with Braunston Marina being recommended by one of the recommendations!

So into the dock we went, I was down there with them and we looked for any faults.

The front part of the rudder was slightly out of line with the back part and the whole rudder was massively out of line with the tiller.  The top bearing had some slop in the part of the hull in which it fits and the bottom bearing was fine except the shaft itself was worn. We also suspected that the rudder was longer than the original as there were impact marks on the hull where the original rudder stopped on full lock and these didn't line up with the new rudder.

We debated the impact of these faults and in the end for lack of a better answer decided to straighten the front bit, repair the bottom of the shaft, make the top bearing a better fit and repair the impact damage to the hull.

So now I have a tiller that is pretty much central when the boat is going straight and doesn't give a nasty clonk when you move past the centre point. 

However there is still some load on the tiller to keep the boat straight - perhaps not as much and it is in a more comfortable position.

 

When in the dock I photographed the new rudder and after some complicated maths (correcting perspective issues) have compared it to the rudder she had when surveyed. 

 

The results - the new rudder is  around 15% longer and the ratio of front to back has changed from about 1:4 to 1:5. The height is similar.

Who thinks I should risk going back in the dock and take 15% off the rudder? 

 

Cheers Graham

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Graham and JoDonate to Canal World

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11 minutes ago, Stilllearning said:

The load on the tiller is probably the natural load one gets from the action of prop walk due to the rotation of the prop.

As Chewbacca says, leave it alone and maybe play with it again at the next blacking.

I will leave it for a bit I think. I'm slightly confused by prop walk as I thought that would make the back end go right  not left. The prop rotates clockwise.

Also it didn't do it before the rudder was changed.

Cheers Graham

 

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RLWP Veteran II

RLWP

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On 14/04/2018 at 10:52, bizzard said:

The rudder blade might be warped sideways, caused by welding and they didn't straighten it afterwards.

And the rest, mate!

We had a small problem two years back which meant having our rudder tube replaced. Only then the rudder wouldn't line up with the skeg because at some point in her hire career it had got bent, and so had the rudder stock. In trying to bend the skeg straight, it fell off

Having put the skeg back straight and true, the rudder stock fouled the rudder tube, so it was cut in half, the blades cut off and welded to a new bottom half of the stock. This was then fitted, which showed the cup was no longer in the right place, so that was replaced

The blades were straightened out before refitting too. I did point out how much more skilful Alvechurch welders were. The boatyard could only weld things straight and true, Alvechurch could weld any old way

Hire boat rudders get cilled, backed into cills and squashed when on full lock and all sorts of other nastiness

Dotterel is also an ex Alvechurch boat

Richard

Oh, and now Tawny steers straight

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RLWP Veteran II

RLWP

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2 minutes ago, WotEver said:

Nahh... you can bend summat and you can then straighten it but to bend something straight is the same as emptying a lock while filling it. 

As the process to go from bent to more bent is identical to bent to straight, can't see the difference myself

Richard

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WotEver Veteran II

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1 minute ago, RLWP said:

As the process to go from bent to more bent is identical to bent to straight, can't see the difference myself

bend

1
[bend]

verb (used with object), bent or (Archaic) bend·ed; bend·ing.

  1. to force (an object, especially a long or thin one) from a straight form into a curved or angular one, or from a curved or angular form into some different form:

 

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RLWP Veteran II

RLWP

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2 minutes ago, WotEver said:

bend

1
 
[bend]

verb (used with object), bent or (Archaic) bend·ed; bend·ing.

  1. to force (an object, especially a long or thin one) from a straight form into a curved or angular one, or from a curved or angular form into some different form:

 

Without using Bold, a thought experiment for you

You have a piece of metal that was straight, now it is bent to the left. In the process of making it straight, what shape is it?

Richard

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WotEver Veteran II

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2 minutes ago, RLWP said:

Without using Bold, a thought experiment for you

You have a piece of metal that was straight, now it is bent to the left. In the process of making it straight, what shape is it?

The bold was simply a copy/paste thing from an online dictionary. 

If you mean that you have straightened the piece of metal from its bent form then it is now straight. Because that is the function of straightening something. 

When the piece of metal was originally changed from straight to bent to the left that was because it had been bent. 

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RLWP Veteran II

RLWP

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Just now, WotEver said:

The bold was simply a copy/paste thing from an online dictionary. 

If you mean that you have straightened the piece of metal from its bent form then it is now straight. Because that is the function of straightening something. 

When the piece of metal was originally changed from straight to bent to the left that was because it had been bent. 

No, I mean you have a piece of metal that is currently bent to the left. You are going to make it straight by applying a force to it (very careful with words). As you make it straight, what shape is it?

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WotEver Veteran II

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2 minutes ago, RLWP said:

No, I mean you have a piece of metal that is currently bent to the left. You are going to make it straight by applying a force to it (very careful with words). As you make it straight, what shape is it?

It is now straight because you have bent it from its original form. So although it might now appear straight, it is in fact bent, as it will no longer fit where it used to. 

If however it started off straight and became bent to the left, the function of making it straight again is to straighten it. 

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rusty69 Veteran II

rusty69

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Posted (edited)

"Do not try and bend the spoon. That's impossible. Instead only try to realise the Truth... There is no spoon... Then you'll see that it is not the spoon that bends, it is only yourself"

Yuri Gellar

Edited by rusty69
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RLWP Veteran II

RLWP

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Just now, WotEver said:

It is now straight because you have bent it from its original form. So although it might now appear straight, it is in fact bent, as it will no longer fit where it used to. 

OK - the metal is currently bent to the left

If you pull the end of the metal until it is straight and let go, it will still have a bend to the left because you have to deform the metal to make it keep it's shape

The only way to make it stay straight is to pull it beyond straight. In other words, you have to bend it to the right

To make it straight (straighten it) you have to bend it, i.e. bend it straight

Richard

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WotEver Veteran II

WotEverDonate to Canal World

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38 minutes ago, RLWP said:

To make it straight (straighten it) you have to bend it, i.e. bend it straight

Almost right. You had to bend it in order to straighten it. You can’t bend something straight. 

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system 4-50 Veteran II

system 4-50Donate to Canal World

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You can bend something straight. Or you can do it later. You can bend something straight "away".

You can bend something straight.  Sufficient force on anything straight will often bend it. You can bend something "that is" straight.

You can bend something straight. If you're clever and can allow for elastic recovery.  You can bend something "to be" straight.

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