Prop problem

[richardh10]

I have just been told that my prop is beyond repair due to electrolysis corrosion. So much for the cheap option!

So what has caused this, and what can I do to avoid it happening again.

Cheers

 

[sailorman]

where r u based

 

[richardh10]

The boat has been on the Orwell for a couple of years, and before that the solent

 

[sailorman]

The boat has been on the Orwell for a couple of years, and before that the solent

swinger or marina

 

[richardh10]

Swinger on Orwell marina in Solent, but I think the problem may have started before I got to the Orwell

 

[sailorman]

Swinger on Orwell marina in Solent, but I think the problem may have started before I got to the Orwell

there are many factors but less likely to be extraneous factors when out on a mooring.

 

[richardh10]

Could the fact that there isn't and never has been an anode have anything to do with it?

 

[sailorman]

Could the fact that there isn't and never has been an anode have anything to do with it?

My 2 bladed MaxProp has no anode but i do have a shaft anode + i have added a small disc anode the P bracket. with us its is dependent where we are in the marina.

 

[gordmac]

Have you had more than one opinion? I was wanting mine overhauled and was told by one company they were done but steel developments did them and they appear to be working fine!

 

[savageseadog]

What make and type of prop is it?

 

[richardh10]

It's a fixed 3 blade brass prop but not sure of the make.

It was steel developments who told me that it was knacked, and it wasn't a huge surprise.

 

[Leighb]

What size is your prop? I have a Volvo LH 14 X 9 bronze prop in good condition if you are interested?

 

[nigelmercier]

Could the fact that there isn't and never has been an anode have anything to do with it?

Quite possibly. What type of drive do you have?

 

[richardh10]

Quite possibly. What type of drive do you have?

It's shaft drive.

 

[nigelmercier]

It's shaft drive.

OK, I'll bow out then. I was going to re-tell a tale of woe

 

[Tranona]

It's a fixed 3 blade brass prop but not sure of the make.

It was steel developments who told me that it was knacked, and it wasn't a huge surprise.

You need an anode bonded to the shaft. Almost certainly galvanic corrosion between the shaft and the prop leading to dezincification. The simplest way is to fit a shaft anode if you have any exposed shaft - for example if you have a P bracket. If not you need a hull anode with a bonding wire to the gearbox with a bridging wire across the coupling if it is the flexible type. The zinc anode will then erode instead of the zinc in your prop.

Good information on the MG Duff website on fitting anodes.

 

[VicS]

You need an anode bonded to the shaft. Almost certainly galvanic corrosion between the shaft and the prop leading to dezincification. The simplest way is to fit a shaft anode if you have any exposed shaft - for example if you have a P bracket. If not you need a hull anode with a bonding wire to the gearbox with a bridging wire across the coupling if it is the flexible type. The zinc anode will then erode instead of the zinc in your prop.

Good information on the MG Duff website on fitting anodes.

Unless of course the prop is replaced with a decent manganese "bronze" one!

 

[Tranona]

Unless of course the prop is replaced with a decent manganese "bronze" one!

If the boat is the one in the OP's profile (Elizabethan 29) then the ideal solution is a Featherstream feathering prop with its in built anode, plus the performance gains - but at a price!

 

[rosssavage]

It's a fixed 3 blade brass prop but not sure of the make.

It was steel developments who told me that it was knacked, and it wasn't a huge surprise.

Yeah, not a fan of Steel a Developments. They told me the same thing on my electrolysis damaged 21x24 prop.

Take it up the road to
http://www.tnorrismarine.co.uk

and they'll fix it. Probably. Did mine no fuss, about £180 and three day turnround. Had three props done by them now, proper old fashioned company

 

[Neil_Y]

Unless of course the prop is replaced with a decent manganese "bronze" one!

There will still be galvanic corossion between a SS shaft and a manganese bronze prop if they are in contact with each other.
You need a zinc anode when any different metals are in contact with each other in water.