Galvanic isolator- is it connected correctly

[Daydream believer]

I am in the process of installing a new engine & saildrive package & noticed something that may have been wrong with the galvanic isolator in the original installation.
I thought that the incoming shore power earth would just have the earth going into the isolator on one side & out the other then into the consumer unit to feed the supplies in the boat ( 3 sets of sockets & the charger)
However, I seem to have another earth wire going from the isolator to the bracket on the saildrive. Presumably to make a path to water.
Is that normal? You tube videos do not show that.
Is the presence of this wire a reason for high anode degregation? - I only use shore power for short term charging & full time when I am away on holiday in other marinas. Is it there as a safety factor?
Is the isolator correctly wired?

 

[Boater Sam]

The earth bonding wire to to the bracket should be on the out side of the GI, nothing should be on the in side other than the shore line earth connection.

 

[vyv_cox]

Some saildrives are totally isolated from the boat, Volvo in particular. These should not have any connection from anywhere. Yanmar saildrives are not isolated but it seems unusual to take an earth connection to it.

 

[PaulRainbow]

I would not connect the earth to the saildrive. If you don't have a hull anode i would fit a small button anode at next lift out.

 

[Tranona]

The button anode is the method used by Bavaria . Nothing should be connected to the saildrive.

 

[Daydream believer]

Thanks. I will ignore the connection to the sail drive then. I will not add an anode just yet I just want to get this engine fitted & the boat back in the water ASAP. It is proving a struggle on my own & I do not want anymore things to distract me. I will look at the anode question at the end of the season. Presumably it will be OK until then.

Unless Paul or Tranona warn against that move

Crane is arranged for Tuesday, best marina can do. Not helped by engine being a week later than promised, due to a missing component

As an aside. I have abraded the hull ready for the fairing rubber. I have not used one for years, as I normally fill the void flush with sponge. This has the advantage that it never falls off & last 7 years OK. But I am in a hurry, so will fit the fairing for this season.
What do others use for antifoul paint on the rubber fairing?

 

[PaulRainbow]

Thanks. I will ignore the connection to the sail drive then. I will not add an anode just yet I just want to get this engine fitted & the boat back in the water ASAP. It is proving a struggle on my own & I do not want anymore things to distract me. I will look at the anode question at the end of the season. Presumably it will be OK until then.

Unless Paul or Tranona warn against that move

Crane is arranged for Tuesday, best marina can do. Not helped by engine being a week later than promised, due to a missing component

As an aside. I have abraded the hull ready for the fairing rubber. I have not used one for years, as I normally fill the void flush with sponge. This has the advantage that it never falls off & last 7 years OK. But I am in a hurry, so will fit the fairing for this season.
What do others use for antifoul paint on the rubber fairing?

What engine are you replacing ?

 

[Tranona]

The anode is to earth the 240v and is optional. It only became compulsory on new boats in the 2013 RCD revisions, but of course many builders were earthing before that. So, no problem leaving it to next haulout. I used that method for my Golden Hind 240v installation as it it is quick and easy to do.

Antifoul the fairing with the same spray as the saildrive housing, in my case I use Hempel Ecopower but the International equivalent does the same job.

 

[Daydream believer]

What engine are you replacing ?

Volvo Penta Md2020 with 120s sail drive - New 2003- with a D1-30 with 130s Saildrive
The old engine suddenly died on May 25Th on way to Ostend. It was running like a sewing machine until it had a heart attack in the last 20 mins of its life
No idea why, but the season is too short to have it apart & sod about, so on the 26Th I ordered a new engine.
Cannot really complain because it has been so reliable up to the last 20 mins. Circa 5500 hours with relatively few problems, that I have not been able to fix myself. Best thing has been its near instantaneous starting throughout its life. Apart , that is for 3-4 glow relays & as soon as I picked up on that, I started to carry spares.

 

[Daydream believer]

The anode is to earth the 240v and is optional. It only became compulsory on new boats in the 2013 RCD revisions, but of course many builders were earthing before that. So, no problem leaving it to next haulout. I used that method for my Golden Hind 240v installation as it it is quick and easy to do.

Antifoul the fairing with the same spray as the saildrive housing, in my case I use Hempel Ecopower but the International equivalent does the same job.

I asked because I thought that the flexing might crack it & it would fall off.

 

[PaulRainbow]

Volvo Penta Md2020 with 120s sail drive - New 2003- with a D1-30 with 130s Saildrive
The old engine suddenly died on May 25Th on way to Ostend. It was running like a sewing machine until it had a heart attack in the last 20 mins of its life
No idea why, but the season is too short to have it apart & sod about, so on the 26Th I ordered a new engine.
Cannot really complain because it has been so reliable up to the last 20 mins. Circa 5500 hours with relatively few problems, that I have not been able to fix myself. Best thing has been its near instantaneous starting throughout its life. Apart , that is for 3-4 glow relays & as soon as I picked up on that, I started to carry spares.

Deleted

 

[Tranona]

I asked because I thought that the flexing might crack it & it would fall off.

Does not seem to. Did it on both my saildrives. Get the odd barnacle but it is so far under water and away from light fouling is limited anyway.

 

[Tranona]

OK. Chances are the Volvo engine was electrically isolated from the leg, so the tiny leg anode only had to protect the leg/prop.

If you just fit a beta engine to your leg you might find the leg has dissolved after a very short time, possibly weeks. If you don't have a hull anode you should fit one before you launch, even if it means a delay.

Bit confusing that. The 130S he is fitting has a huge anode to protect the leg but not the prop which has its own anode.

Don't think there is any need for a hull anode if you hook up a Beta to the old 120 (which he is not doing) as that drive also has its own anode. No real need for hull anodes on any saildrives although some people do as a backup to the leg anode should that go quickly. More common on the old 120 as that has a smaller anode, but both the 130 drives I had would go 3 or 4 years before changing anodes.

 

[PaulRainbow]

Bit confusing that. The 130S he is fitting has a huge anode to protect the leg but not the prop which has its own anode.

Don't think there is any need for a hull anode if you hook up a Beta to the old 120 (which he is not doing) as that drive also has its own anode. No real need for hull anodes on any saildrives although some people do as a backup to the leg anode should that go quickly. More common on the old 120 as that has a smaller anode, but both the 130 drives I had would go 3 or 4 years before changing anodes.

My bad, i confused this with another thread where someone was fitting a Beta engine.

There is of course no need for a hull anode for the OPs combination as the new saildrive will be isolated from the new engine.

I've edited my original post accordingly.

 

[Tranona]

Thats OK. Anodes are on the top of my list at the moment as I lifted my GH on Thursday to change the pitch on the Featherstream and the anode was just about gone including one screw missing after only 8 months. I had hoped to avoid a hull anode as the boat had never had one with the old fixed blade prop.

Fitted a new one and will lift again in October to fit a hull anode. A bit complicated as I have a Bullflex coupling so will have to figure out a way of bridging it so that I can bond the anode to the gearbox. All good fun.

 

[Daydream believer]

I doubt that the new 130S anode will last more than a season. I have had to machine a lot of the centre away to accommodate my stripper. The standard 120 s ones only lasted a season. The Brunton anode will have to be changed, even though it was new at launch in April. Not because it has totally gone now, but because it would not last 2 more months & I usually have to change it mid season when I come out to have the copper coat jet washed.
Your advice re not connecting the saildrive to the isolator may solve an issue here

 

[vyv_cox]

I doubt that the new 130S anode will last more than a season. I have had to machine a lot of the centre away to accommodate my stripper. The standard 120 s ones only lasted a season. The Brunton anode will have to be changed, even though it was new at launch in April. Not because it has totally gone now, but because it would not last 2 more months & I usually have to change it mid season when I come out to have the copper coat jet washed.
Your advice re not connecting the saildrive to the isolator may solve an issue here

Painting the prop reduces the cathode size and doubles (at least) anode life. My Bruntons anode now lasts two years since the Hammerite/Velox treatment.

 

[Daydream believer]

Painting the prop reduces the cathode size and doubles (at least) anode life. My Bruntons anode now lasts two years since the Hammerite/Velox treatment.

Obviously whole life experience beats theory every time. But there must be a theory behind it. So what is it?

 

[Tranona]

Obviously whole life experience beats theory every time. But there must be a theory behind it. So what is it?

Exactly what he says. The galvanic circuit is between the two metals in the electrolyte (seawater) and if you reduce the size of the cathode (the blades) exposure by painting you reduce the strength of the circuit so the anode lasts longer.

I shall be painting my Featherstream in the winter because after lifting to change the pitch last Thursday, found the anode almost gone after 8 months. I was reluctant to paint or fit a hull anode (it is shaft drive) until I knew how long the anode would last.

You leg anode should last longer than the 120 even after you have taken a lump out because of its greater bulk. I only changed mine once in 6 seasons afloat year round and that is reduced bulk because of the Stripper.

 

[William_H]

The common connection of a GI is in series with the mains earth line coming in. However there seems to be an alternative arrangement where the collected earth lines of the mains equipment is connected to the sea via a GI. Hence possibly explaining the GI connection to the engine. That might be ok if all metal parts in contact with water are also connected to engine earth. I doubt your wear on anodes has been caused by mains connection if you are not connected 24/7. ol'will