Prop update

Firefly625

Firefly625

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Sorry to bore you, but an update for those who are interested....

So down to Hamble yesterday and got my prop off, looks horrible but I started to think perhaps I could file down the worst and it may be fine for another season... so spend a merry hour with my grinder with wire brush attachment, filled my garage with dust & here it is now I have cleaned all the crud off, well its shiny.....;

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OK, so I know it has had its day....& taking everyone's advice and decided to bite the bullet and called Clements who in fact supply Hardy. This prop in fact came from them and is a 21" diameter, 22" pitch LH Rotation Clements Hyperform which today retails for a cool £863.65, when I asked for their best price they did throw in P&P.... I was expecting less than half that:eek:
 
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Firefly625 said:
OK, so I know it has had its day....& taking everyone's advice and decided to bite the bullet and called Clements who in fact supply Hardy. This prop in fact came from them and is a 21" diameter, 22" pitch LH Rotation Clements Hyperform which today retails for a cool £863.65, when I asked for their best price they did throw in P&P.... I was expecting less than half that:eek:
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That prop is just serviceable as it is.
Clearly there is an electrolysis issue.
I would add an anode to both sides of the rudder.
Put your prop back on for 6 months/year, brush it clean again and compare the photos, if you stop the electrolysis corrosion then by all means splash out on a new prop. , but I would be keen to make sure I stop the electrolysis before I wreck another prop.
 
dacarak said:
That prop is just serviceable as it is.
Clearly there is an electrolysis issue.
I would add an anode to both sides of the rudder.
Put your prop back on for 6 months/year, brush it clean again and compare the photos, if you stop the electrolysis corrosion then by all means splash out on a new prop. , but I would be keen to make sure I stop the electrolysis before I wreck another prop.
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Firefly has already found, and cured, the electrolysis problem that the previous owner of the boat let drag on for too long thus knackering the prop. And adding anodes to the rudder of all places wouldn't be a cure anyhow!

Firefly I think you need to bite the bullet. You could continue to use that prop and just eat the extra fuel burn, or you could fair it with filler to stop the drag, etc, but when you sell the boat you'll suffer a £800 haircut when the buyer's surveyor sees it, so mght as well get a new one imho. Before splashing out on the £800 I'd ask steel developments if they can put new metal onto it and fair it with a grinder for much less than £800
 
jfm said:
Firefly has already found, and cured, the electrolysis problem that the previous owner of the boat let drag on for too long thus knackering the prop. And adding anodes to the rudder of all places wouldn't be a cure anyhow!

Firefly I think you need to bite the bullet. You could continue to use that prop and just eat the extra fuel burn, or you could fair it with filler to stop the drag, etc, but when you sell the boat you'll suffer a £800 haircut when the buyer's surveyor sees it, so mght as well get a new one imho. Before splashing out on the £800 I'd ask steel developments if they can put new metal onto it and fair it with a grinder for much less than £800
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Thanks for all your info, indeed I certainly believe I have solved the electrolysis issue. In fact I believe this damage was done within a 12 month period as i have a survey that the previous owner had done in May 2008 when he split with his partner who owned a half share in the boat, at the time all the issues that the survey pointed out were rectified and the costs were shared between the two, obviously benefitting the shrewd previous owner... but if there was an issue with the prop in May 08 that too would have been replaced, and the survey clearly stated the prop was OK...

I am a little broke at the moment so before just buying new I will speak to Steel Developments to see what they think.
 
update

Steel developments say if pitted through electrolysis it will have drawn zinc out of prop and not possible to fill/weld.... a new one would be £800.... I guess an improvement on Clements... but not OEM
 
jfm said:
Firefly has already found, and cured, the electrolysis problem that the previous owner of the boat let drag on for too long thus knackering the prop. And adding anodes to the rudder of all places wouldn't be a cure anyhow!
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I wasnt aware the problem had been cured, (does anyone until next lift out ?) if it is a stainless steel rudder and the bronze prop is within a stainless steel A frame, adding an anode to the stainless steel A frame will safeguard the prop, if the anodes dont erode they can be taken away next lift out.
A lot of hardy's are used in fresh water 90% of the time and only 10% sea water, using zinc anodes in fresh work but get gummed up with calcium like coating, putting the anodes on the rudder keeps the calcium build up to a minimum so the zinc anodes work in fresh water and salt water.
There was not enough room to fit a shaft anode, not many would want to DIY a hull anode, even if this hardy does not see fresh water the rudder having a good view of the prop and being attached to the stainless a frame makes a possible anode site.

It is such a cheap and easy DIY job that can be so easily removed if i am wrong but could save a second £800 prop.

Just my opinion, I have not fitted anodes to rudders myself but I have seen many.
 
dacarak said:
I wasnt aware the problem had been cured, (does anyone until next lift out ?) if it is a stainless steel rudder and the bronze prop is within a stainless steel A frame, adding an anode to the stainless steel A frame will safeguard the prop, if the anodes dont erode they can be taken away next lift out.
A lot of hardy's are used in fresh water 90% of the time and only 10% sea water, using zinc anodes in fresh work but get gummed up with calcium like coating, putting the anodes on the rudder keeps the calcium build up to a minimum so the zinc anodes work in fresh water and salt water.
There was not enough room to fit a shaft anode, not many would want to DIY a hull anode, even if this hardy does not see fresh water the rudder having a good view of the prop and being attached to the stainless a frame makes a possible anode site.

It is such a cheap and easy DIY job that can be so easily removed if i am wrong but could save a second £800 prop.

Just my opinion, I have not fitted anodes to rudders myself but I have seen many.
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Dacarak..thanks to your tenaciousness.....starting to warm to your idea, I have replaced copper wire from brush contacts to anode, I have checked contact from anode to prop and now all connected and OK. I wouldn't attach an anode to the rudder, but I could attached a prop shaft type anode to the tail end of the bottom rudder tube frame, just where the frame starts to rise up to the bottom of the rudder, it would surely not do any harm? I would be hopping mad if next year I pulled the boat out and saw my lovely new prop eaten away!

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anodes

I cannot see any anodes on the trim tabs, we have 2kg do-nut types on ours, (they are stainless steel) and were are the main anodes? on ours they are close in the vicinity of the props. Also make sure your gearbox/shaft coupling is bridged.
 
omega2 said:
I cannot see any anodes on the trim tabs, we have 2kg do-nut types on ours, (they are stainless steel) and were are the main anodes? on ours they are close in the vicinity of the props. Also make sure your gearbox/shaft coupling is bridged.
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Indeed there are 2 large disc anodes on the stainless steel trim tabs, I will check gearbox/shaft coupling... I am sure it it is bridged. Thanks for your pm, I have taken note.
 
First of all, you do have a beautiful boat!
I think the hull is GRP. Mine is as well and although the propshaft has no anodes, the prop is still fine after 15 years. In fact, there is only 1 anode on the complete boat and this is on the propshaft of the bowthruster. Why is my prop still ok? What is the difference?
 
FlyingDutchman said:
First of all, you do have a beautiful boat!
I think the hull is GRP. Mine is as well and although the propshaft has no anodes, the prop is still fine after 15 years. In fact, there is only 1 anode on the complete boat and this is on the propshaft of the bowthruster. Why is my prop still ok? What is the difference?
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Firstly thank you for your kind comments.

Secondly anodes (& prop shaft brushes connected to anodes) should protect against galvanic corrosion or your underwater metal gear... so your stopcocks, prop shaft & prop, rudder (if metal) , if you only have an anode on your entire boat and that is on your bow thruster all I can assume is you do not have shore power and neither does any boat near to you....anyone else got any ideas? or has the flyingdutchman found the answer to put MG duff out of business? ;)
 
Firefly,

I don't have shorepower, but several boats directly next to ours have this.
Somehow, I don't understand the anode's functioning. Take the propshaft as an example:
The shaft is stainless steel, the prop is bronze (or whatever). I understand that there is a difference is electrical potential between the two different metals but as they are linked together what can happen?
I have always wondered why my boat does not have anodes (except for he very small one on the shaft of the bowthruster). The boat is on fresh water and nothing has happened in the past 15 years but I would like to prevent future problems. Or maybe I really have invented something...
 
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