Starlight 35 Anode / Engine Grounding

[eagle160]

Hi all - tried to place this at Sadler's Association forum but access hasn't been forthcoming... Hopefully some Starlight 35 owners around here...

Summary: When trying to replace the hull anode on my recently bought Starlight 35 1998, the through-hull bolt turned without me noticing, winding 2 grounding wires attached to it around it and in the process separating them from the ends . Should be an easy job to refit the wires however I can't seem to find where one of them was connected to.

The situation is as follows, hopefully this makes sense !

-No shaft anode, only through-hull Anode placed approx 20 cm to the starboard side of the shaft coupling
-No p-bracket (epoxied, presumably from when built)
-One of the ground wires is long and goes to the engine raw water inlet (now re-attached), the other one is about 25-35 cm and isn't really long enough to go anywhere other than close to the anode
-DSS shaft seal
- volvo md2030

So the remaining grounding wire is too short to reach much and can only really reach the bracket that holds the engine throttle cable. After looking for 30 minutes with 2 ppl it cannot seem to have been connected anywhere else obvious. However I can't see a sign that it was attached there recently (or ever).

The manual states it should be attached to the P bracket and engine. However, this isn't the situation as one of them definitely was installed to the engine inlet seacock, and the P bracket isn't there.

I can see 3 situations:
1. All the ground wires were fitted incorrectly and should be changed;
2. The grounding for perhaps the engine or perhaps the p bracket wasn't done correctly and this wire was left unattached and too short. The engine should be grounded differently; or
3. My conclusion so far. The ground wires are correct and should go onto the bracket that holds the engine throttle, which is connected to the reverse gear - which obviously is connected to the engine. However as it goes over the shaft this doesn't look like a very safe way of fitting the grounding so I'm left with this nagging feeling I've missed something somewhere!

All help is appreciated but I suspect a fellow Starlight owner might be able to let me know the solution! thanks

 

[VicS]

Generally these days it is considered incorrect to connect skin fittings / seacocks to the anodes. They should be made of a corrosion resistant alloy such as bronze or DZR brass. I'd feel inclined to disconnect it. It was one of the MAIB recommendations in their report on the near loss of the F.V. Random Harvest a few years ago

Take care with MD2030. IIRC it has an isolated engine block ( not used as the negative return except via an earthing relay during preheating and starting) and is insulated from the transmission.

ITYWF the anode should be connected directly to the gearbox casing .. certainly if its intended to protect the stern gear. The flexible coupling must be bridged, of course, to complete the circuit.

 

[Steve Clayton]

Eagle.....

There's a Starlight 35 just come into our marina. If they are still here in the morning I'll pop over and have a chat re the anode and wiring points and let you know.

Possible I just ask them for an email address. PM me your email address so I can hopefully pass it to them and then the two of you can hook up as necessary

 

[Tranona]

With your current arrangement the prop is not protected. However, if you have a folding or feathering prop, chances are it will have its own anode which may well be enough. As VicS says, there is no need to connect the anode to the water inlet, although it won't do any harm.

So, if you need the hull anode (which is physically in the right place) it needs to be connected to the gearbox casing and a bridge across the coupling if it is the flexible kind.

Suggest you check whether there is an anode on the prop, and if it is not excessively wasted, no need for the hull anode as it is clearly not doing anything with the prop now.

 

[Plevier]

Take care with MD2030. IIRC it has an isolated engine block ( not used as the negative return except via an earthing relay during preheating and starting) and is insulated from the transmission.

ITYWF the anode should be connected directly to the gearbox casing .. certainly if its intended to protect the stern gear. The flexible coupling must be bridged, of course, to complete the circuit.

The MD2030/2020 etc are indeed insulated from the transmission but the engine is no longer isolated and does not use an earthing relay. That is what VP did prior to introducing the insulation between engine and gearbox, you don't need both.
It is the transmission that they tell you not to earth. The engine block is OK.
That is the case for my 2003 year MD2020D with VP MS10 gearbox (which is in fact a ZF-Hurth) anyway, it's possible that very early A series ones were different but I don't think so.

Later - looking at the manuals, the one for the original 2030 shows an earthing relay on the starter, but in the manual for the 2030B it has disappeared.

 

[eagle160]

With your current arrangement the prop is not protected. However, if you have a folding or feathering prop, chances are it will have its own anode which may well be enough. As VicS says, there is no need to connect the anode to the water inlet, although it won't do any harm.

So, if you need the hull anode (which is physically in the right place) it needs to be connected to the gearbox casing and a bridge across the coupling if it is the flexible kind.

Suggest you check whether there is an anode on the prop, and if it is not excessively wasted, no need for the hull anode as it is clearly not doing anything with the prop now.

Thanks for that, I was also wondering about the prop. The current setup is that it doesn't have an anode (there's no space on the shaft due to rope cutter fitted). There's no sign of corrosion and I would expect the current setup to have been like this for at least 3 years, and being in the water for all that time.
The short wire must therefore have been used for the prop, but in the absence of the P-bracket I still wonder where it was attached...
I guess the shaft connects to that reverse gear which then connects to the bracket where the grounding wire now is attached but not sure whether there's a circuit there and if this even works if there is a circuit

 

[Tranona]

Going to a P bracket does nothing for the prop because the shaft is insulated from the P bracket by the bearing. The only path to the prop is through the shaft, and as this turns the only way you can do it is to use the special device that MG Duff sells that uses brushes on the shaft, or wired through the gearbox casing as already described. The Duff device is not always suitable because on many yachts there is not enough room to fit it. Your boat would not normally have a shaft anode, even if you did not have a rope cutter as there is insufficient clearance between the stern bearing and the prop. Depending on your prop you can get an adaptor to fit an anode on the locking nut.

 

[VicS]

The MD2030/2020 etc are indeed insulated from the transmission but the engine is no longer isolated and does not use an earthing relay. That is what VP did prior to introducing the insulation between engine and gearbox, you don't need both.
It is the transmission that they tell you not to earth. The engine block is OK.
That is the case for my 2003 year MD2020D with VP MS10 gearbox (which is in fact a ZF-Hurth) anyway, it's possible that very early A series ones were different but I don't think so.

Later - looking at the manuals, the one for the original 2030 shows an earthing relay on the starter, but in the manual for the 2030B it has disappeared.

Some terrible conflicts to find a way through.

If the block is not isolated but is insulated from the gearbox and they tell you not to earth the gearbox it seems , except with folding props with their own anodes, its then necessary to rely on a shaft anode if there room to fit one, or an "electro-eliminator " if thats feasible, or a tiny prop anode.

Perhaps in reality a good bronze or manganese brass prop on a stainless steel shaft does not need the protection of an anode at all!

Not sure why with a shaft drive the gearbox should not be earthed anyway.

 

[eagle160]

Some terrible conflicts to find a way through.

If the block is not isolated but is insulated from the gearbox and they tell you not to earth the gearbox it seems , except with folding props with their own anodes, its then necessary to rely on a shaft anode if there room to fit one, or an "electro-eliminator " if thats feasible, or a tiny prop anode.

Perhaps in reality a good bronze or manganese brass prop on a stainless steel shaft does not need the protection of an anode at all!

Not sure why with a shaft drive the gearbox should not be earthed anyway.

I have to admit I'm getting a bit confused...The engine is a 2030B and this is what the manual states about the electrical system:

• Unipolar electrical system
• The fly wheel cover and the transmission (reverse gear) are electrically insulated from the engine

There's no space for an anode on the shaft (or prop I think -it's folding) so either it doesn't need an anode or the protection is through the anode being connected to the reverse gear somehow... the manual so far doesn't seem to shed any light on this, other than what's stated above but that means nothing to me (I'm quite new to this!).

edit: no space to fit anode on the folding prop I believe

edit 2: the manual also states this:
"WARNING! The flywheel housing or transmission (reverse gear alt. S-drive) must under no circumstances be earthed. Earthing of these components can result in serious damage as a result of galvanic corrosion."

So that answers the question I guess that the transmission should not be grounded. However it leaves me wondering why the anode has 2 wires and where the mystery wire has to then connect to...? The engine block?

 

[VicS]

I have to admit I'm getting a bit confused...The engine is a 2030B and this is what the manual states about the electrical system:

• Unipolar electrical system
• The fly wheel cover and the transmission (reverse gear) are electrically insulated from the engine

There's no space for an anode on the shaft (or prop I think -it's folding) so either it doesn't need an anode or the protection is through the anode being connected to the reverse gear somehow... the manual so far doesn't seem to shed any light on this, other than what's stated above but that means nothing to me (I'm quite new to this!).

edit: no space to fit anode on the folding prop I believe

edit 2: the manual also states this:
"WARNING! The flywheel housing or transmission (reverse gear alt. S-drive) must under no circumstances be earthed. Earthing of these components can result in serious damage as a result of galvanic corrosion."

So that answers the question I guess that the transmission should not be grounded. However it leaves me wondering why the anode has 2 wires and where the mystery wire has to then connect to...? The engine block?

I have now downloaded what should be the manual for the "B" series of engines but so far though I have not found the statements you refer to in your post.

I'll try to take another look later ( chores to do this afternoon .. or I'll be in trouble again)

Are you sure that warning about earthing the transmission is not in fact referring to an S drive? I cant see why there will be a problem with a shaft drive gear box. It's not immersed in seawater like a sail drive. Sail drive legs have their own anodes and the props have their own anodes too.

If you have a folding prop it will almost certainly have its own anodes, even on a shaft drive, due to the mix of metals used in the construction ( the exception being the plastic bladed ones )


The wires that don't appear go anywhere could of course be redundant and disconnected when a folding prop was fitted ?????

 

[eagle160]

I have now downloaded what should be the manual for the "B" series of engines but so far though I have not found the statements you refer to in your post.

It's on page 79 under Galvanic corrosion, with a little picture. The picture is of a sail drive but the description refers to reverse drive as well.

If you have a folding prop it will almost certainly have its own anodes, even on a shaft drive, due to the mix of metals used in the construction ( the exception being the plastic bladed ones )

The wires that don't appear go anywhere could of course be redundant and disconnected when a folding prop was fitted ?????

There are no anodes on the prop but this doesn't mean there weren't any in the past...Not sure where they would fit though, they would be very difficult to reach if they would've been present I guess.

Re the wire being redundant this is a possibility of course...It did have engine oil on the end suggesting it could've been lying under the engine (there was some oil leakage under the engine before a recent engine service).

All in all it sounds like something was amiss anyway, but I'm now not sure what the best setup should be to be bring it back to what it should be...

 

[Plevier]

Some terrible conflicts to find a way through.

If the block is not isolated but is insulated from the gearbox and they tell you not to earth the gearbox it seems , except with folding props with their own anodes, its then necessary to rely on a shaft anode if there room to fit one, or an "electro-eliminator " if thats feasible, or a tiny prop anode.

Perhaps in reality a good bronze or manganese brass prop on a stainless steel shaft does not need the protection of an anode at all!

Not sure why with a shaft drive the gearbox should not be earthed anyway.

Vic, I agree but it's what the VP manual says!
I assume it does literally mean earth, with leakage currents in mind; I don't think it means "don't connect to an anode."

 

[Tranona]

Attaching an anode to the gearbox casing is not grounding it. You are just creating a path from the prop and shaft to the anode.

If you have a Flex o Fold 2 blade folding prop like mine it does not need an anode. other folding props vary - some eat anodes and often have 2 or 3 little ones and others don't. If you are not experiencing any dezincification of the prop then you don't need an anode. If there are no signs that the anode has been wired to the gearbox then it has probably never had any protection. So leave well alone.

 

[VicS]

It's on page 79 under Galvanic corrosion, with a little picture. The picture is of a sail drive but the description refers to reverse drive as well.



There are no anodes on the prop but this doesn't mean there weren't any in the past...Not sure where they would fit though, they would be very difficult to reach if they would've been present I guess.

Re the wire being redundant this is a possibility of course...It did have engine oil on the end suggesting it could've been lying under the engine (there was some oil leakage under the engine before a recent engine service).

All in all it sounds like something was amiss anyway, but I'm now not sure what the best setup should be to be bring it back to what it should be...

I think I have looked at all the manuals that are on line but obviously different versions to yours as none runs to 79 pages.

However I think I have found the diagram you are looking at under the heading "Electrical installations".

The text I am reading says that the drive/reverse gear and flywheel cover are electrically insulated from the engine and must never be used as a ground. This is not quite the same thing a saying that it must not be earthed.

If a piece of electrical equipment were connected to it there would be a path back to the common ground terminal and battery negative via the saildrive or possibly a shaft driven prop and the water which could result in electrolytic corrosion of the drive or prop. Not just galvanic corrosion but electrolysis driven by the 12 volt system.


My thoughts as to what you should do are:

Is it a folding prop which should have its own anodes ... if so renew them and replace them as and when necessary. Forget about connecting the hull anode.

Is it a fixed prop with provision to fit an "prop nut" anode. If so renew it and replace it when necessary. Forget about connecting the hull anode.

Is it a fixed prop which is showing no signs of corrosion. Do nothing but keep it under review with regular inspections.

Is the prop showing signs of corrosion. If so connect the anode directly to the gear box casing and nothing else. Bridge the flexible coupling to complete the circuit to the prop.

 

[eagle160]

Vics, Thanks a lot for your help. Having checked the again my prop definitely doesn't have an anode (http://www.marinepartseurope.com/en/volvo-penta-explodedview-7744440-44-4206.aspx , it's the lower one) so probably the hull anode is/was used for that purpose or it doesn't need an anode. I will try and speak to volvo to get to the bottom of this

Bridge the flexible coupling to complete the circuit to the prop.

Sorry to ask a silly question but how would you bridge the flexible coupling?

 

[Tranona]

If you do have that prop, then it clearly has anodes - #10 on the parts list. Essential you fit them as that is a type that eats anodes - which is probably why you can't see any!

If you have a flexible coupling, it will have either rubber dampers or will be a plastic disc between the coupling on the gearbox and the one on the shaft. This means the bolts don't go through from one coupling to another. The mormal way to bridge them is to use a braided copper link from the bolt on one side to a bolt on the other.

 

[eagle160]

If you do have that prop, then it clearly has anodes - #10 on the parts list. Essential you fit them as that is a type that eats anodes - which is probably why you can't see any!

That part no is only relevant for the S drive prop, the one I have is the one in the 2nd picture that doesn't have a no 10 fitted?

 

[Tranona]

Sorry - yes, you are right. Maybe it will be OK if it does not have an anode. As I said earlier if there is no evidence that the hull anode has been bonded to the shaft and prop through the gearbox, then it has not been doing anything. Those props have a chequered history and there have been changes in the alloy used. The vulnerable parts are the pins so worth checking they are OK then probably OK to leave as it is. However, as the hull anode is there it might make sense to bond it as already suggested, using a bridging wire if the coupling is flexible. Not necessary if the coupling is a solid metal to metal type.

 

[eagle160]

thanks a lot for all the help so far everyone. I will have further investigation when I go back to the boat.

Edit: I've been contacted by a fellow Starlight owner who has confirmed the setup used:

1. one wire to seacock
2. one wire to gearbox only , the shaft coupling is non-flexible and hence provides the grounding for the prop and shaft without having to bridge the coupling, and that explains absence of anode on the prop.

Thanks all!