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Whilst my boat was in for blacking at Debdale Marina, Gail suggested that the fore part of the rudder ahead of the pivot could be extended by a couple of inches to good effect. I bowed to her superior knowledge and £40 later the job was done.

Got my first chance to test it today and I must say, boat handling has been dramatically improved, the tiller is much lighter, and for the first time, I was able to do a 360 turn at the foot of Foxton locks without reversing. When I came to reverse back on to my mooring, for the first time ever the boat actually "steered", allowing much greater precision.

That was one of the best £40 I've spent on my boat ... thanks to Gail for suggesting it (and doing a great job of the blacking), and Gordon for welding on the 30cm x 9cm x 6mm extension .

20121004_111636.jpg

 

Rudder before the extension was added. Unfortunately I wasn't able to photograph the extension before she went back in the water.

Edited by Kwacker
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Hi Kwacker

 

We to can thank Debdale and Gail, she did an excellent job of blacking ours about two weeks ago. Her mantra is to do the job as she would like it done on her own boat.

 

We noticed, whilst the boat was in the air, the propeller nut was lose even though split pin was in situ, ???

 

No problem, it was all checked and sorted and a stainless steel tab washer fitted, instead of the pin. (saves drilling a new hole for a split pin)

Edited by bottle
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Whilst my boat was in for blacking at Debdale Marina, Gail suggested that the fore part of the rudder ahead of the pivot could be extended by a couple of inches to good effect. I bowed to her superior knowledge and £40 later the job was done.

Got my first chance to test it today and I must say, boat handling has been dramatically improved, the tiller is much lighter, and for the first time, I was able to do a 360 turn at the foot of Foxton locks without reversing. When I came to reverse back on to my mooring, for the first time ever the boat actually "steered", allowing much greater precision.

That was one of the best £40 I've spent on my boat ... thanks to Gail for suggesting it (and doing a great job of the blacking), and Gordon for welding on the 30cm x 9cm x 6mm extension .

20121004_111636.jpg

 

Rudder before the extension was added. Unfortunately I wasn't able to photograph the extension before she went back in the water.

 

Interesting as that looks exactly the same setup as ours which is a Bellaires shell, built by Peter Bellaires and/or his son who used to build for Floating homes. I have often toyed with doing your mod and now I feel more confident it will be beneficial.

 

I forget what the ratio between the front and back parts of the rudder is meant to be. Is it one-third to two thirds?

 

Ours is identical and is 25/75 ratio which could do with the mod mentioned which would bring it to about one third/two thirds ratio.

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Hi Kwacker

 

We to can thank Debdale and Gail, she did an excellent job of blacking ours about two weeks ago. Her mantra is to do the job as she would like it done on her own boat.

 

We noticed, whilst the boat was in the air, the propeller nut was lose even though split pin was in situ, ???

 

No problem, it was all checked and sorted and a stainless steel tab washer fitted, instead of the pin. (saves drilling a new hole for a split pin)

That is very curious, as we had exactly the same problem about two years ago having a gap of a few mm between the nut and the prop (it was tight at previous blacking). My only conclusion (probably incorrect) is that there was some sort of sacrificial anode in the form of a washer?

 

Tab washer is a good solution. Wish I had thought of that instead of re drilling the nut.

Edited by Guest
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That is very curious, as we had exactly the same problem about two years ago having a gap of a few mm between the nut and the prop (it was tight at previous blacking). My only conclusion (probably incorrect) is that there was some sort of sacrificial anode in the form of a washer?

 

Tab washer is a good solution. Wish I had thought of that instead of re drilling the nut.

 

When we fitted a different prop I had to put some extra packing washers in so cut some from various thicknesses of polypropelyne with a hole saw (3mm 6mm and 8mm IIRCC) did the job a treat and no worries about corrosion.

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That is very curious, as we had exactly the same problem about two years ago having a gap of a few mm between the nut and the prop (it was tight at previous blacking). My only conclusion (probably incorrect) is that there was some sort of sacrificial anode in the form of a washer?

 

 

Another likely cause is that the prop was a poor fit on the taper, or the key was 'high', so that although initially apparently tight it had worked loose and worked its way up the taper.

 

Tim

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Interesting as that looks exactly the same setup as ours which is a Bellaires shell, built by Peter Bellaires and/or his son who used to build for Floating homes. I have often toyed with doing your mod and now I feel more confident it will be beneficial.

 

It is indeed a Bellaires shell ... well spotted that man. Go for it!

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Interesting as that looks exactly the same setup as ours which is a Bellaires shell, built by Peter Bellaires and/or his son who used to build for Floating homes. I have often toyed with doing your mod and now I feel more confident it will be beneficial.

 

 

 

Ours is identical and is 25/75 ratio which could do with the mod mentioned which would bring it to about one third/two thirds ratio.

Be careful, don't overdo the balance piece or you'll end up with negative helm ''Too light and the tiller won't self centre'' when let go of but whips over onto full helm, this horrid trait makes the boat horribly uncomfortable to steer and in a moment of inattention can put the boat up the bank. :help:

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Another likely cause is that the prop was a poor fit on the taper, or the key was 'high', so that although initially apparently tight it had worked loose and worked its way up the taper.

 

Tim

 

This was the thought (key was high) at the time from the staff, the prop, key and taper were checked and no untoward wear could be found.

 

The prop was tight on inspection two years ago at last blacking.

 

The gap between the washer and the prop was about the thickness of a steel rule.

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This was the thought (key was high) at the time from the staff, the prop, key and taper were checked and no untoward wear could be found.

 

The prop was tight on inspection two years ago at last blacking.

 

The gap between the washer and the prop was about the thickness of a steel rule.

These keys need careful checking before the prop nut is finally tightened up,'' careful filing of the key if needed to ensure they're not too proud and to prevent the jambed cocked prop fit on the taper. I don't think this amongst a lot of other things a lot of modern day so called marine engineers understand. The bad fitting of props and keys often goes hand in hand with rubbish, badly aligned modern engine installations.

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Be careful, don't overdo the balance piece or you'll end up with negative helm ''Too light and the tiller won't self centre'' when let go of but whips over onto full helm, this horrid trait makes the boat horribly uncomfortable to steer and in a moment of inattention can put the boat up the bank. :help:

 

We've just bought a new (to us) boat and the surveyor recommended cutting an inch off the forward part of the rudder to improve handling. At the moment she handles much as explained above. Does anyone have a formula to arrive at the correct ratio or is it a different fit for each hull.

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We've just bought a new (to us) boat and the surveyor recommended cutting an inch off the forward part of the rudder to improve handling. At the moment she handles much as explained above. Does anyone have a formula to arrive at the correct ratio or is it a different fit for each hull.

 

The 'traditional' formula I've always believed to be one-fifth - four-fifths, but clearly the OP already had at least that and is happier with more. A lot is down to personal preference, my personal preference is to have plenty of feedback which implies a modest amount of balance area. The OP's boat has quite a large gap between prop and rudder, which may be one reason why a large balance area seems better.

 

Tim

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The 'traditional' formula I've always believed to be one-fifth - four-fifths, but clearly the OP already had at least that and is happier with more. A lot is down to personal preference, my personal preference is to have plenty of feedback which implies a modest amount of balance area. The OP's boat has quite a large gap between prop and rudder, which may be one reason why a large balance area seems better.

 

Tim

 

We have an identical rudder to the OP and we also have less than ideal turning when winding, ok once the boat is rotating but sluggish initially, hopeless in reverse but fine in forward. I do wonder if having such a large gap between prop and rudder is part of the problem of initial response, on reflection and looking at pics of the rudder we and the OP have probably got less than 20% ahead of the pivot, adding to that will, I am sure, improve things as it has done with the OP. I will probably increase it as much as possible, easier to reduce it later on with an angle grinder rather than trying to add it on.

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We have an identical rudder to the OP and we also have less than ideal turning when winding, ok once the boat is rotating but sluggish initially, hopeless in reverse but fine in forward. I do wonder if having such a large gap between prop and rudder is part of the problem of initial response, on reflection and looking at pics of the rudder we and the OP have probably got less than 20% ahead of the pivot, adding to that will, I am sure, improve things as it has done with the OP. I will probably increase it as much as possible, easier to reduce it later on with an angle grinder rather than trying to add it on.

 

On two or three boats with a large gap like that I have fitted a vertical plate between prop and rudder, with some success being reported in improved handling.

 

Tim

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We have an identical rudder to the OP and we also have less than ideal turning when winding, ok once the boat is rotating but sluggish initially, hopeless in reverse but fine in forward. I do wonder if having such a large gap between prop and rudder is part of the problem of initial response, on reflection and looking at pics of the rudder we and the OP have probably got less than 20% ahead of the pivot, adding to that will, I am sure, improve things as it has done with the OP. I will probably increase it as much as possible, easier to reduce it later on with an angle grinder rather than trying to add it on.

 

 

 

Hi Chris

 

I have always held the opinion that a good gap between prop and rudder is conducive to good handling.

It gives the water time to produce a directed stream of water onto the rudder, a smaller prop would also increase the likely hood of producing this stream.

A big prop near the rudder (IMHO) just splashes against the rudder.

But who knowsblush.gif

 

Alex

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Is it not, the amount that the forward part 'covers' the prop when turned that has the effect of improving or not, the of steering of the boat..

 

Not forgetting the distance from the prop of the rudder, in the straight ahead, can also have an effect on the 'stability' in the tiller.

 

:wacko::blink:

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On a related topic, what do people think about those horizontal 'fins' just below the waterline that some people have on their rudders? I think they're meant to direct the prop thrust over the rudder area rather than it being lost as turbulence above the waterline. In that sense I suppose on a canal boat they act as a continuation of the uxter plate. But would adding them to a rudder increase rudder judder?

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On a related topic, what do people think about those horizontal 'fins' just below the waterline that some people have on their rudders? I think they're meant to direct the prop thrust over the rudder area rather than it being lost as turbulence above the waterline. In that sense I suppose on a canal boat they act as a continuation of the uxter plate. But would adding them to a rudder increase rudder judder?

 

 

I think that they are a cheap and simple way of meeting some EU requirement for a way for someone in the water climbing out. They form a pair of treads.

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I think that they are a cheap and simple way of meeting some EU requirement for a way for someone in the water climbing out. They form a pair of treads.

 

But completely useless for that purpose. Just how would anybody get themselves out of the water unassisted using them? You can't haul yourself out on a step which is higher than most of your body mass when you are in the water.

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I think that they are a cheap and simple way of meeting some EU requirement for a way for someone in the water climbing out. They form a pair of treads.

 

Yes, I've heard they have that function too, but don't they also improve thrust?

 

Personally I don't like the idea of anyone climbing back onto the boat on a swinging rudder. Why put anyone who's cold, wet and tired nearer to a prop than they need to be - even if the prop's not spinning? My boat just has a couple of semicircles that stick out from the uxter plate.

Edited by blackrose
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But completely useless for that purpose. Just how would anybody get themselves out of the water unassisted using them? You can't haul yourself out on a step which is higher than most of your body mass when you are in the water.

 

 

You may be able to with the swan neck to hang onto - depends on the strength in your arms.

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