Active Galvanic current at work.

[Tranona]

Sadly, I get paid to fabricate as the owner wishes. I did offer an "opinion" but owner knows best and wanted it like it was before even after I mentioned that the "before" caused its rudder to drop off and melted everything.

Hull anode is connected to a supposed earth and engine. Nothing made much sense to me but the "old Guard" at the marina knows best and I keep quiet and do what I’m told. They all been "sailing" for 30 years of course.
However I’m listening with attention to your opinions here as I have my own circuits to make.

The only place the hull anode should be connected to is the gearbox housing to provide a path to the prop. Not sure what the "earth" is but should not be connected to the anode. The skin fittings and stern tube can only corrode if there is current passing through them, so remove any wires attached to them. Appreciate not your responsibility, but the owner(or his advisers seem to have no idea of the principles involved. Well explained on this site. mgduff.co.uk

Suggest you pass it on to the owner.

BTW nice fabrication work.

 

[PaulRainbow]

The only place the hull anode should be connected to is the gearbox housing to provide a path to the prop. Not sure what the "earth" is but should not be connected to the anode. The skin fittings and stern tube can only corrode if there is current passing through them, so remove any wires attached to them. Appreciate not your responsibility, but the owner(or his advisers seem to have no idea of the principles involved. Well explained on this site. mgduff.co.uk

Suggest you pass it on to the owner.

BTW nice fabrication work.

It's an RCD requirement that the AC Earth be connected to the water, often done by using the anode. I believe your Bavaria has a very small anode just for this purpose ?

But, big but, the LM would not have had such a connection from new and any such connection would require that a galvanic isolator or isolation transformer be fitted.

EDIT: the RCD requirement is for newer boats.

 

[GregOddity]

The only place the hull anode should be connected to is the gearbox housing to provide a path to the prop. Not sure what the "earth" is but should not be connected to the anode. The skin fittings and stern tube can only corrode if there is current passing through them, so remove any wires attached to them. Appreciate not your responsibility, but the owner(or his advisers seem to have no idea of the principles involved. Well explained on this site. mgduff.co.uk

Suggest you pass it on to the owner.

BTW nice fabrication work. Thank you

Thanks for the link. Will pass on to owner. I had a cursory look at the wiring and could not make sense of the principle used. Owner had been working on the engine and I believe a new alternator and may have changed the wiring.

 

[GregOddity]

It's an RCD requirement that the AC Earth be connected to the water, often done by using the anode. I believe your Bavaria has a very small anode just for this purpose ?

But, big but, the LM would not have had such a connection from new and any such connection would require that a galvanic isolator or isolation transformer be fitted.

No idea. I really could not make sense of the wiring or why it is connected to everything. Owner is more receptive now as he saw that the new rudder is being affected and the problem needs solving.

 

[Tranona]

It's an RCD requirement that the AC Earth be connected to the water, often done by using the anode. I believe your Bavaria has a very small anode just for this purpose ?

But, big but, the LM would not have had such a connection from new and any such connection would require that a galvanic isolator or isolation transformer be fitted.

EDIT: the RCD requirement is for newer boats.

i know - but as you say irrelevant to an old boar like this which does not require an anode except to protect the prop. Anybody who puts an anode on a piece of 316 stainless and then connects it to a bronze cutless housing clearly has no clue. In the earlier photos even the casing of the cutless was eaten away and looks like th shaft is also damaged where it goes through the cutless. The rudder and shaft may need a bit of investigation as it is unclear whether the shaft and the connecting bracket are 316, same as the new blade. would also make sense to have a delrin bush for the lower pintle to isolate the rudder from the skeg as well as provide a good bearing.

Something seriously wrong here.

 

[PaulRainbow]

i know - but as you say irrelevant to an old boar like this which does not require an anode except to protect the prop.

I'd be very cautious about recommending removal of Earth wiring, we don't know if the boat has an inverter, for instance. I might be tempted to leave the Earth wire in place but fit a GI or IT

Anybody who puts an anode on a piece of 316 stainless and then connects it to a bronze cutless housing clearly has no clue. In the earlier photos even the casing of the cutless was eaten away and looks like th shaft is also damaged where it goes through the cutless. The rudder and shaft may need a bit of investigation as it is unclear whether the shaft and the connecting bracket are 316, same as the new blade. would also make sense to have a delrin bush for the lower pintle to isolate the rudder from the skeg as well as provide a good bearing.

I think we all agree with that lot. Is that a first for PBO

Something seriously wrong here.

Indeed.

I very rarely say this on these forums, but this is definitely NOT a PBO job it requires someone who knows what they are doing to sort it properly.

 

[GregOddity]

i know - but as you say irrelevant to an old boar like this which does not require an anode except to protect the prop. Anybody who puts an anode on a piece of 316 stainless and then connects it to a bronze cutless housing clearly has no clue. In the earlier photos even the casing of the cutless was eaten away and looks like th shaft is also damaged where it goes through the cutless. The rudder and shaft may need a bit of investigation as it is unclear whether the shaft and the connecting bracket are 316, same as the new blade. would also make sense to have a delrin bush for the lower pintle to isolate the rudder from the skeg as well as provide a good bearing.

Something seriously wrong here.

I did add a delrin bush on the skeg to protec the shaft. That was my first thought and the owner agreed when I sugested it.

 

[GregOddity]

What you need to understand is that these are very small marinas, mostly old folk that instead of sailing just spend their time tinkering with the boats instead of going sailing. They will all tell you that they have been “sailing for 30 years “and yet rarely went even close to the harbour mouth in Portsmouth. They go fishing and once a year they make a "passage"… to Bembridge. “someone” they know told them that “this is the way to do it” and that is how they do it until it all goes horribly wrong.

Having said that they have their fun tinkering and actually take pride on their boats and are always giving either a lick of paint or changing something on the boat. At this stage it matters not what they do as long as they themselves are happy. They “sail” like this and it works for them.

You should see the knots and lines on the boats, but they do come and ask when they get stuck so who am I to judge.

The gentleman in question is a bit long in the tooth and the centre of a family. He uses the boat as a shed. However, upon asking my advice on a few matters he learned how to splice and redid all his mooring lines, installed self-tailing winches to make the boat easier for him to handle, installed new clutches and moved the deck hardware around to maximise it’s use.

When it comes to the wiring, he’s done some work on the engine and may have damaged the wiring.

“someone” said that this is how it should be done and that’s how it somehow got done. They sit together having endless cups of tea and share knowledge that way.

Is it a PBO job? No, it ain’t that’s for sure but then again most of them still do not own a smart phone. Let alone post on the PBO forum.

Which again leads to Why I am posting the problem here so I can actually try to understand what’s what and at least point him in the right direction.

 

[GregOddity]

I'd be very cautious about recommending removal of Earth wiring, we don't know if the boat has an inverter, for instance. I might be tempted to leave the Earth wire in place but fit a GI or IT



I think we all agree with that lot. Is that a first for PBO



Indeed.

I very rarely say this on these forums, but this is definitely NOT a PBO job it requires someone who knows what they are doing to sort it properly.

I did advise to get someone in that actually knows what they’re doing. I know literally nothing about the subject. The owner spoke to some marine engineer in the Hamble area that “explained” what was supposed to happen. I was merely tasked with drilling holes and tapping some of them. Best advice I gave was that I knew nothing about it.

 

[Tranona]

I'd be very cautious about recommending removal of Earth wiring, we don't know if the boat has an inverter, for instance. I might be tempted to leave the Earth wire in place but fit a GI or IT

But if an earth is needed perhaps it should not be connected to the anode that seems to be part of a bonding system. The earth is the only thing connected to the anode on my boat - and seems the anode does not wear very much. Only one change after 2 years because it got bent by the sling and replacement good as new after a further 3.

You are right, somebody needs to go back to square 1 for this boat - but it is not difficult from the anode point of view as there is only one thing that needs an anode and that is the prop. As there is no room for a shaft anode the only alternatives are a small prop nut anode, or the existing hull anode that looks in pretty good shape. Otherwise strip out any bonding wires from the seacocks, stern tube and rudder tube and shaft. Remove those 2 big zincs from the stainless bits as they can do nothing. Pretty sure problem will go away.

 

[pvb]

You are right, somebody needs to go back to square 1 for this boat - but it is not difficult from the anode point of view as there is only one thing that needs an anode and that is the prop. As there is no room for a shaft anode the only alternatives are a small prop nut anode, or the existing hull anode that looks in pretty good shape. Otherwise strip out any bonding wires from the seacocks, stern tube and rudder tube and shaft. Remove those 2 big zincs from the stainless bits as they can do nothing. Pretty sure problem will go away.

If the boat is routinely on shore power, a galvanic isolator would be a very good idea.

 

[Tranona]

It would indeed, but from the way Greg described the "marina" maybe no shorepower. Anyway not sure that is where the problem lies.

 

[pvb]

It would indeed, but from the way Greg described the "marina" maybe no shorepower. Anyway not sure that is where the problem lies.

From the way he described the marina, I'd think it must certainly have shore power.

 

[GregOddity]

there is shore power, but they very seldom connect to it. To complicate matters further there's a big mild steel (60 footer) power boat close by that is connected to shore power full time.
I’m thinking at this stage square one is the way to go. Disconnect everything except to the Hull anode and see what happens then go from there. I do think that there’s a fault in the system that is causing a slow loss somewhere and that’s what’s causing such violent reaction. I must admit I do not really know what he’s got on board but I’m going to have a conversation with him tomorrow and see what’s happening with the wiring. I was surprised to see a cable connected to the rudder shaft. I was told it was disconnected but I still see the anodes fizzing away.

 

[PaulRainbow]

But if an earth is needed perhaps it should not be connected to the anode that seems to be part of a bonding system. The earth is the only thing connected to the anode on my boat - and seems the anode does not wear very much. Only one change after 2 years because it got bent by the sling and replacement good as new after a further 3.

At a risk of possible thread drift (although it could be revenant in terms of the Earth/GI/IT:

When your BAV was built it was required to have the AC Earth connected to "the water" (for grounding purposes). As it didn't actually need an anode and had no ground plane, wasn't a metal hull, it had few ways to get an electrical connection to the water, so Bav fitted a small anode to make the connection and comply,. You should have a GI or IT. The anode depletion should be minimal, at worse.

My Westerly was not required to have such a connection and has never had one (I don't have an inverter, which would change that). The hull anode is connected to the gearbox, as you previously describe (the coupling is not a flexible one). After two years it's almost as good as new,

The LM would also have not had the Earth connected to the water when it was built. If it has not had any changes made, such as fitting an inverter that would require an Earth, it still does not require that connection. If, for any reason whatsoever, that connection has been made, it needs a GI or IT. If there is no requirement for the connection (being extremely careful to be 100% certain it isn't required), it could be disconnected. But, it would likely be better/safer to fit a GI/IT.

You are right, somebody needs to go back to square 1 for this boat - but it is not difficult from the anode point of view as there is only one thing that needs an anode and that is the prop. As there is no room for a shaft anode the only alternatives are a small prop nut anode, or the existing hull anode that looks in pretty good shape. Otherwise strip out any bonding wires from the seacocks, stern tube and rudder tube and shaft. Remove those 2 big zincs from the stainless bits as they can do nothing. Pretty sure problem will go away.

Completely agree, get rid of those bonding wires, without them the through hulls, cutless housing and stainless "skeg" etc would have/will be unaffected. The anodes would be unessessary, as you say. The hull anode could be connected to the gearbox, if there is a flexible coupling a bridging wire could be fitted.