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Saildrive disappeared...

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Category: Hints & Tips
Forum Name: 370 / 375
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URL: https://www.myhanse.com/forum_posts.asp?TID=2036
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Topic: Saildrive disappeared...
Posted By: RSchrHH
Subject: Saildrive disappeared...
Date Posted: 14 April 2008 at 13:09

http://farm4.static.flickr.com/3145/2405261698_6266151f13.jpg?v= - These are the remains of the saildrive of my 370 after just five months in water.

It is completely unclear so far how this could possibly has happend.
 
Hanse Germany is not at all interested in solving the problem.
 
There is rumour that several other Hanses are affected.
 
Anyone here?


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Hanse 370 - Baltic Sea



Replies:
Posted By: Nereide
Date Posted: 14 April 2008 at 13:53
Well, this is amoung the most astonishing posts yet,
i could only think that a 12v cable was connected continuously to either motor block or sail drive and provided the sufficent current for a major electrolysis phenomena to occur in that short space of time, this would also imply that cutting off the batteries while not onboard was ineffective??
 
never ever heard of this on a Hanse, and very shocking to say the least,


Posted By: Peter-Blake
Date Posted: 14 April 2008 at 14:15
This post is already some days on www.yacht.de
So far i stay calm until i get an information, that this is not fake.
It is just to unreal to me.
but may be it is not.
 
I wrote already to the yanmar importer who has been told having seen same problem on several other boats. I wait for the comments from Yanmar.
Also my Hanse dealer never heard of this, and he told me that this is not a Hanse Problem, only if true it may be a Yanmar problem.....Confused
 
I post new information as far as i get some.
 
I will post the answers i get from Hanse and from Yanmar.


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Blake 370


Posted By: RSchrHH
Date Posted: 14 April 2008 at 14:56
Originally posted by Peter-Blake Peter-Blake wrote:

So far i stay calm until i get an information, that this is not fake.
 
It is not a fake, believe me.


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Hanse 370 - Baltic Sea


Posted By: Peter-Blake
Date Posted: 14 April 2008 at 14:59
Let us know your Hull number please

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Blake 370


Posted By: RSchrHH
Date Posted: 14 April 2008 at 15:03
Originally posted by Peter-Blake Peter-Blake wrote:

Let us know your Hull number please
 
#316


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Hanse 370 - Baltic Sea


Posted By: Johan Hackman
Date Posted: 14 April 2008 at 15:11
I believe someone had a similar problem with their http://www.skota.se/insp/files/38a92a672f0a7db764bb17a5825e36da-288.html - keel . It's not a Hanse, but nevertheless.

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: Peter-Blake
Date Posted: 14 April 2008 at 15:11
Sorry RSchrHH,
 
i was not sure if it was real.
Now i know from your PM that it is not fake.
Sorry for that.
Good luck with your repaired saildrive.
Let us know please what Hanse will do and what the solution for you boat is, as far as you know


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Blake 370


Posted By: RSchrHH
Date Posted: 14 April 2008 at 15:15
Originally posted by Johan Hackman Johan Hackman wrote:

I believe someone had a similar problem with their http://www.skota.se/insp/files/38a92a672f0a7db764bb17a5825e36da-288.html - keel . It's not a Hanse, but nevertheless.

Johan
 
Yes, looks very similar indeed to my saildrive! Wink


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Hanse 370 - Baltic Sea


Posted By: alettaenmarcel
Date Posted: 14 April 2008 at 15:17
I have seen this before on a boat in Holland in Hellevoetsluis on a Compromis 888.
Only it did not go this far and it had onley holes in the saildrive.
I do believe it is true because the man from the Compromis said the year before it was still OK and hade new anodes and a year after it was relaunches the saildrive failed and had holes in it.
I believe that wenn it would have stayed in the water longer it would finaly has fallen off like we do see on the picture wich hasa been posted above.
Succes unforunally ownerConfused
greetings Marcel
(i think it is an electric problem wich can also be caused by for exemple  a neigbour vessel)


Posted By: Scorpio
Date Posted: 14 April 2008 at 15:25
The photograph strikes me as somewhat odd.
 
I accept that saildrive cast casings can (and do) corrode if not adequately protected by an anode.
 
I find it strange that, if the casing has corroded all the way through, why are some of the internal parts of the saildrive not visible - they would have been exposed to the water for less time and would be made of a more noble metal which would have taken longer to corrode and therefore I would expect at least something to be sticking out of the bottom of the casing.
 
For a saildrive to corrode away like this, there must have been a significant amount of current flowing.  Where was the boat moored?  What was the cathode in this reaction?
 
Ed


-------------
Ed Essery
Scorpio GBR 9824T
Hanse 342#465 - Solent Based


Posted By: panos
Date Posted: 14 April 2008 at 17:49
Very unlucky owner!
IMHO the cause of this severe electrolysis might be in the water or in the shore power connection or even worse in both. A wrongly installed shore power battery charger, a steel boat nearby, a leaky marina cable nearby, lead battery dumped in the water under the boat etc etc...


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Panos

Hanse 630e - selling her -


Posted By: christian
Date Posted: 14 April 2008 at 20:56
I think this broke while hoisting.

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Hanse 370e # 346
X Hanse 312 #247
1991 11:Metre One Design 2003 Stingray 5,2 RIB 90 Suzuki X First 25 X First Class 8 X Triss Norlin


Posted By: Junker
Date Posted: 15 April 2008 at 13:31
Hi
I'm not sure how the laws around are.
But one thing is for sure. If you buy a brand new Hanse and this happends, it IS a HANSE problem.
How they sort it out with Yanmar, seller or other sub suppliers is not the owners problem. The boat has been bought in one piece, and the warranty follow this piece.  If the reason for a failure can be proven to be something the owner has done wrong, the story will be diferent.
 
I can see in many discussions around that various suppliers tries to push the responability over to the sub suppliers. They are entiteled to do so, but this should not affect the buyer of the final product. This is controlled by the terms and condition between the builder and sub supplier.
 
If this should be the case, we could all start buying our boats in bits and pieces and assembly them our self. (this is a general statement not only for Hanse)
 


Posted By: RoyP
Date Posted: 15 April 2008 at 20:59
It hardly seems possible, so we look forward to hearing what might have caused it!
 
But, ref comment about switching off batteries when away from boat - clearly it is sensible for several reasons, but in my 350 (#104) if you want to leave bilge pump on auto, the battery must be left connected and so potentally increasing this problem of electolysis.
 
In my previous boats a bilge pump was connected directly to battery, with own inline fuse, so everything else could be disconnected while leaving an operational bilge pump.


Posted By: panos
Date Posted: 15 April 2008 at 21:40
Hi,
 The battery cannot affect electrolysis so we can let the switches on. On the contrary , the shore power if it doesn't include a very good quality isolation transformer can create a ground loop and destroy all  metal objects (aluminium or steel) inside the water (including the saildrive and the steering shaft ). The boat or saildrive manufacturer has little to do with this ,like a tire manufacturer of a car ,if you drive it over nails. Unless of course the damage is because of a faulty shorepower battery charger installed by the boat manufacturer. All this IMHO of course.


-------------
Panos

Hanse 630e - selling her -


Posted By: Nereide
Date Posted: 16 April 2008 at 08:29

As Panos quiet rightly points out, the anodes could include the sail-drive and the rudder stock, both aluminium.

It could be important to understand the degree of corrosion (electrolyte) on the rudder stock, to determine whether the cause is "internal" or "external" ?


Posted By: RoyP
Date Posted: 16 April 2008 at 09:24
One good clue as to whether damage was caused by "internal" or "external" causes would be if similar damage was caused to other nearby boats.
 
If moored against a pontoon with metal in water (such as emergency boarding ladders, piles etc) were they damaged?
 
Or was this moored well away from anything else?


Posted By: les40
Date Posted: 16 April 2008 at 09:40
[QUOTE=Junker]Hi
I'm not sure how the laws around are.
But one thing is for sure. If you buy a brand new Hanse and this happends, it IS a HANSE problem.
How they sort it out with Yanmar, seller or other sub suppliers is not the owners problem. The boat has been bought in one piece, and the warranty follow this piece.  If the reason for a failure can be proven to be something the owner has done wrong, the story will be diferent.
 
I can see in many discussions around that various suppliers tries to push the responability over to the sub suppliers. They are entiteled to do so, but this should not affect the buyer of the final product. This is controlled by the terms and condition between the builder and sub supplier.
 
If this should be the case, we could all start buying our boats in bits and pieces and assembly them our self. (this is a general statement not only for Hanse)
 
junker,
 
unfortuantely, this is true........for my boat, agent is not interested in helping meAngry, i get either "no reply or we are very busy". i too believe the problem is hanse's and they should help and not leave it to their agents who are not helpful.
 
my boat is 6 monhs old and the agent has yet to fixed anything for me. i had to install my own autopilot!! (it was fun though) and many more minor problems. 
 
to get yanmar warranty, the engine needs to be commissioned by yanmar or their appointed representative. it is in the file when you receive your boat. if you don't, your engine is not covered.
i was lucky i called them(yanmar) as when i had an engine fault, they fixed it under warranty.
 
my point is this, for all parts....agent has to help, but if they do not, hanse have to step in even though they seem reluctant.
 
 
i do envy those who bought their hanse's from agents who care. Clapwhen i do order another hanse, i'll get another agent.
 
leslie
 
 
 
 


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TODAK 2


Posted By: Johan Hackman
Date Posted: 16 April 2008 at 12:17
RSchrHH, do you happen to have any more photos of your saildrive? I would like to see what it looks like from under.

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: MatsG
Date Posted: 16 April 2008 at 19:54
It has to be some electrical problem.
Did you have continously shore power?
Some grounding problem? Have you measured the voltage between grunding on shore socket and water? Voltage between zero and grounding in shore socket?
Isolation error between red plus pole and motorgrounding?
Too much damage I think to be error i galvanic isolation, galvanic current, I think, is to weak to make such a big destruktion(!?)
Is there any damage in the motor?
/Mats

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MatsG 371


Posted By: alettaenmarcel
Date Posted: 21 April 2008 at 08:06
Hallo
I have been reading the isotherm boiler using guide.
In there it is said that there is a possibility for eletro galvanic working if the boiler is not in use for a longer time.
http://www.isotherm.com/prodpdf/1463/2/ManBasic_Slim07.pdf - http://www.isotherm.com/prodpdf/1463/2/ManBasic_Slim07.pdf
read it for yourself in the language you prefer and maybe this will help.
greetings Marcel
 


Posted By: RSchrHH
Date Posted: 25 April 2008 at 12:38
There has been an investigation by several experts from Hanse, Yanmar and the insurance company on the boat the day before yesterday. They have taken measurements for more than four hours - on shore and in water. No fault has been found.
 
So there are only two possbilities: Either it has happend due to an external incident (e.g. underwater welding nearby, very unlikely) or the aluminium alloy of the saildrive was erroneous. This will be investigated further in a specialized lab.
 
I'll let you know as soon as I know more.
 
Rolf


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Hanse 370 - Baltic Sea


Posted By: Johan Hackman
Date Posted: 25 April 2008 at 12:48
Rolf, do you have any more pictures? It would be interesting with a close-up, if you have one.

Did you get any leaks?

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: Ron Taylor
Date Posted: 07 May 2008 at 21:49
I've heard of this happening on a yacht moored for several months on it's anchor chain. The circuit was via the common on the electric windlass supply back to the battery and engine ground.
 
Ron


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Western Flyer


Posted By: copain
Date Posted: 04 December 2008 at 17:48
Hi all,

In respect to the previous posts here an article on Electrolysis.

http://www.jefa.com/install/electro.htm

Regards, Willem

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s/y Copain (Beneteau 281)
from march 2008 Hanse 350 # 061
Visit my BLOG op http://www.wsv-haringvliet.nl/blog/maatje/


Posted By: Bereklauw2
Date Posted: 08 December 2008 at 22:48
Thanks Willem! Exellent stuff!


Boudewijn


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Arwen, Hanse 370, #401, former owner of Mirage, Hanse 291. "Real men don't use bowthrusters!"


Posted By: Yeoman
Date Posted: 09 December 2008 at 15:16
Hi Folks,
 
We have had two similar cases in the past 24 months and Hanse germany have in both cases sent specialists over immediately to do numerous tests and sort the problem out.
 
It turns out that there were almost three times the cases when Hanse used another major marine engine manufacturer, so it is certainly not limited to Yanmar.
 
I would be very surprised to hear that Hanse Germany or Yanmar are not keen to investigate as they could not have done more for us in both situations.


Posted By: Peter Russell
Date Posted: 09 December 2008 at 19:44
We have just hauled out for the year and I was dreading the state the anodes would be in.  On inspection little pitting and no sign of damage elsewhere.
 
We've been on a swinging mooring so that will help.  On a previous boat I've lost anodes (and a stainless rudder stock) very quickly due to what was probably an electrical fault.


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Peter Russell

Hanse 370 hull 499 "Outnumbered"



http://outnumbered.the-russells.net" rel="nofollow - http://outnumbered.the-russells.net


Posted By: Netzerab
Date Posted: 14 December 2008 at 12:52
This case is not as odd as it seems. Yes, the consequences are extreme, but the problems regarding elecrolytic corrossion are everyday problems for the average boat owner.

So what can cause this extreme corrosion? The magic words are known as "shore power"

Saltwater.  Your boat floats in it.  Another name for it is electrolyte. Your saildrive? It can be an anode or it can be a cathode. In cases regarding galvanic corrossion the most noble metal is the cathode. In the world of electrolytic corrossion, you actually do not now. It all depends what way the electrons will move and that all depends what is the positive and what is the negative part of the circuit - and of course that we do hav a closed circuit. Well, you can call it by its real name. It is called a battery. And in your case your saildrive is the anode in the circuit. You can call it a sacrificial anode. The thing that gets eaten that is.


So how does the saildrive get eaten up in the first place? Well, normally it would not. That is of course only the case if your boat, every elses boat and the shore power all are without any fault. The chance for this to happen is of course much smaller than winning the the lottery and become a billionare.

Given the fact that there is always  some kind of a fault somewhere, your boats underwate rpart is about to get electrolytically corroded and eventually disappear. Well at least those part that has some kind of connection to battery minus. And what parts would  that be? Well, if your boat has an engine that is not electrically isolated, then battery minus is connected to the engine block. And guess what? The engine block is elecricalle connected to your saildrive, propeller, maybe a rudder, some seacoocks.... most underwater metal parts actually.

And guess what again? Hanse do connect shore power ground with battery minus, and so do most boat builders. Is this plain stupidity? No, not at all. This is according to the given safety regulations. These regulations takes care of the personell safety, not the safety of your zincs or other metal parts.

Given these circumstances, we are now ready for the corrosion devil to do his job. Fortunately this job is still a tuff one to acomplish.  A ground fault interceptor on shore will cut the circuit off in case of a ground fault. But then again, your boats health depends on wheather this interceptor works or not. And, if it works, it would still not cut off these small currents in the range of 5-10-20 and up to 30 mA or whatever the trigging current may be. And these currents will definately harm your boat. But then again - only if your boat become the anode in the circuit. Do you feel lucky? Perhaps not, but there was a chance that your boat could have been the protecting cathode in the circuit. A 50% chance acutually.

Five monts with shore power connected. Five monts with at large ground fault.  Sorry mac. This is not the boat buiolders problem. This is not the engine manufacturers problem. This is your problem and yours only. sh*t happends. 

And for all the rest of us? There is only one safe solution to the problem. Do get rid of the shore power ground cable. The problem is that this cable is there to save your life in case of a fault. If you cut it, you have to have a better  - and a legal - alternative. The altarnative is called an isolation transformer. Another alternativ is to disconnect the ground wire from the battery minus and then only use double isolated electrical equipment. A third alternative is to enable a local earth plane on board. An excellent alternative like how it is done in most homes and legal to do on boats in many countries. Local earth plane is as simple as an underwater metal part of a given size which do make an excellent job in transporting the ground falt current safely back to its source without causing harm to your boat, the other boats or to any swimmers nearby. The salt water is an excellent conductor - much more safe than a questionable shore ground wire and even more important a far better conductor than the human body.


Posted By: Netzerab
Date Posted: 14 December 2008 at 13:20
Not to be misunderstood: It is the AC-currents that are dangerous to people. It is the DC potential differences that will cause the electrolytic corrosion.

A battery om board with a charger connected is well capable of corroding away most underwater part given the time. Battery minus is already connected to the engine and most underwater parts.  All we need to have is an  insulation fault in some positive wire or equipment that has a connection to the salt water. A pump perhaps? Something else? You now has a circuit driven by at 12V battery. This is eight times more the potential between the most noble metal and zinc.  Underwater metal will disappear in a hurry.


Posted By: Johan Hackman
Date Posted: 14 December 2008 at 19:20
How am I supposed to sleep well at night now?

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: bjoris
Date Posted: 14 December 2008 at 21:30
Originally posted by Johan Hackman Johan Hackman wrote:

How am I supposed to sleep well at night now?

Johan
 
It is really easy, disconnect your shorecable! It is true, this is the only way, if you dont want to use a lot of money.
 
I never use shorepower for more than 24 hours at the same place. Then I have charged my batteries and can use them instead. I also try to have a close look at the zink. If I need to varm up a bit to avoid freezing now in the winter I do take the shorepower cable directly onboard, not thru the shorepower in the boat.
 
Bee awar that this might be dangerous, but not if you ensure that there is no power on when there is people in the boat! Very important!


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H350#118
www.bjoris.blogspot.com


Posted By: Johan Hackman
Date Posted: 14 December 2008 at 22:36
Or else I could just get rid of the sail drive. Who needs it anyway? It's a sail boat...

I might not fully understand this but I have been thinking that as long as the plug to the water heater is disconnected the ground of the shore power will be isolated from the water. Whatever you connect to the shore power sockets will be grounded though.

The water heater chassis will be connected to shore power ground and as it is connected to the water inside it will also will be connected to the water in the engine which comes from the water the boat lies in.

I recently re-wired parts of my electrical system and I can't see how the shore power ground would be connected to anything else than what's put into the sockets. However, I just got aware that the minus of the charger is connected to the engine since they are both connected to battery minus.

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: Scorpio
Date Posted: 14 December 2008 at 22:52
I am shortly going to install a Galvanic Isolator - this is effectively a big diode which goes in the shore power earth cable.  It allows earthing current flow ashore from your boat but no current flow down the earth wire from shore to your boat.  It's a lot cheaper solution than a full isolation transformer - I'm planning to these guys http://www.safeshoremarine.com/ - http://www.safeshoremarine.com/  (or at least I hope Santa Clause is!)
 
Ed


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Ed Essery
Scorpio GBR 9824T
Hanse 342#465 - Solent Based


Posted By: Stephen
Date Posted: 15 December 2008 at 07:08
Hi All
 
Recently looked at sail drive anode and std 2 blade prop on my 411.  Anode was 30% worn but prop was conmpletly destroyed by corrosion.  Big holes and a tip nearly broken off.
 Replaced prop and installed Galvanic isolator.  Since then no issues  YET.  Shore power is always connected.  In my view Its a simple cheap fix,
 
 Install an Galvanic isolator just after the shore power socket. and sleep easy.
 
Stephen


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Stephen Kerr


Posted By: bovine
Date Posted: 15 December 2008 at 19:13
hi all
 
    why would anybody leave the shore power connected when not on board crazy  david


Posted By: colincooper
Date Posted: 15 December 2008 at 19:40
I agree.  I always disconnect shore power when not aboard.  Also cuts fire risk. If you need to keep batteries topped with infrequent visits up get solar.

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Colin (owner of Hilde - a 370)


Posted By: Stephen
Date Posted: 15 December 2008 at 19:57
Hi Colin and David,
 
Most owners here in cold Scotland leave the shore power connected to run electrical items such as de-humidifiers and small 60 W tube heaters to ensure the yacht is not subject to freezing or mould growth. Its not that crazy an idea. 
 
Guys -- Do the sensible thing and fit the  Galvanic isolator.  That what all the experts say.
 
 LOL
 
Stephen


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Stephen Kerr


Posted By: greyghost
Date Posted: 15 December 2008 at 20:11
Hi guys,

Interesting discussion. I have had my 342 plugged in to shore power more often recently. When I hauled out a few weeks ago, I noticed my (smallish) prop zinc was gone and electrolysis was beginning to attack the prop itself. Nearby saildrive zinc showed normal wear. Looking around a bit, I found my boat was fitted with a ZincSaver galvanic isolator. So, I'm left wondering if my prop was attacked simply because the zinc collar wore out or if, as it seems to me, the collar is wearing out preferentially. Aside from my unresolved questions, it seems a galvanic isolator may not necessarily be the entire solution. At least for some of us...

Cheers,
Doug

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Cheers,
Doug

Grey Ghost 342 #405


Posted By: Rubato
Date Posted: 15 December 2008 at 20:12
Same thing here in Vancouver - shore power connected when at berth. In winter, it runs the dehumidifier and/or heater. All year round, it keeps the batteries topped up. These types of batteries last a lot longer if you keep them at float charge when not in use....
 
Netzerab, I followed your explanation, most of us are well aware of the basics of electrolysis. However, at the end, where you mention that "A third alternative is to enable a local earth plane on board" I didn't understand the logic. Isn't this just moving the problem? It's an attempt to make another piece of metal the target of connecting the circuit, the same thing we try to do with the zincs. The same challenges exist, how to make that "other piece of metal" the target instead of the vital metal pieces of the boat.
 
Steve


Posted By: colincooper
Date Posted: 15 December 2008 at 20:27
Well if you run small heaters and dehumidifiers then power is needed.  A galvanic isolator will def. help.  - but ....   Both are mains presumambly - and so don't need to touch the 12V circuits.  You could run them and not endanger saildrives etc. 
 
 


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Colin (owner of Hilde - a 370)


Posted By: 371-#235
Date Posted: 16 December 2008 at 20:35
I leave my shorepower plugged in all season as well. Cold beer in the fridge and my Mastervolt battery charger looks after my batteries very well.
 
To prevent galvanic corrosion problems I installed a marine isolation transformer ( http://www.charlesindustries.com/main/ma_iso_bost.html - http://www.charlesindustries.com/main/ma_iso_bost.html ) from Charles industries.
 
Now my shorepower is completely isolated by means of a transformer whose windings transfer shorepower to the boat magnetically without any shorepower wires actually touching my boats's wires. It is far superior to a galvanic islolater.
 
Bob, 371-#235


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Bob
371-#235
"Blondie"


Posted By: bovine
Date Posted: 16 December 2008 at 21:07
hi
   why not run a lead from shore power to inside of your yacht and plug your heaters or dehumidifier that way your boat is isolated.
             david


Posted By: bjoris
Date Posted: 16 December 2008 at 21:30
Well, there are quite a lot of people that means that zinkSavers is not doing all the work. There are only two perfect solutions. Complet galvanic Isolator or disconect your shorepower. I do it like bovine, but it might be dangours since you then do not have earth in your boat...

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H350#118
www.bjoris.blogspot.com


Posted By: Stephen
Date Posted: 16 December 2008 at 21:42
 
Its accepted practice to leave the shorepower connected for heaters and battery charging etc.   Its what's the best solution to minimise the risk of galvanic corrosion in doing  just that.
 
Probably wise to fit some sort of isolator.  Bob's idea is probably the best input Ive read so far  on this discussion. 
 
If my Galvanic isolator fails then  its next on the list.
 
Stephen.


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Stephen Kerr


Posted By: alettaenmarcel
Date Posted: 16 December 2008 at 22:15
Till now we always have shore power connected wenn we are not on board.
We did not make any electrical chanches to the electrical installation only added nav gear.
Til now no problems at all.
we leave the shore power connected because we dont switch off the fridge and there is always somting in it we have to keep cool (there is nothing better then wenn you arive on board and you can get a nice can off beerSmile
Besides that there are hundreds off boats other than Hanse witch also have the shore power in and also have a volvo ore Yanmar saildrive.
I think we have to keep looking if thing stay alright but dont overdo it to yourself.
greetings Marcel
 


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Kids Dingys 72-79 ,Several Windsurfboards 79-86 OK dingy competitions 86-92 , Trotter Pandora Race 92-98, Friendship 28 Sport 98-05, Hanse 370 06-......


Posted By: Johan Hackman
Date Posted: 16 December 2008 at 22:38
Originally posted by bovine bovine wrote:

hi
   why not run a lead from shore power to inside of your yacht and plug your heaters or dehumidifier that way your boat is isolated.

             david


I also need to keep heaters in the boat during the winter and the way I see it my boat is isolated as long as the water heater is not connected. I will have to find out whether the charger actually connects the shore power with the water. The good thing is that I have a switch so I can turn it off. Does anybody else have that?

If I thought that it was not enough to pull the plug to the water heater I would definitely follow David's advice.

My boat's home port is in fresh water and I haven't seen any abnormal wear on the anodes. Judging by that I think I won't have to worry.

Johan

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http://www.johanhackman.se" rel="nofollow - http://www.johanhackman.se


Posted By: Andis
Date Posted: 17 December 2008 at 12:34
Johan
 
I don't think the water heater is the main source for possible problems. I've been talking to fellow sailors that have experienced real problems with these matters, and they don't even have one installed.
Beeing in fresh water should presumably reduce the problem however (not such a good lead).
I'll not for a second pretend to be an expert on these matters, but as far as I can understand, the only really safe and foolproof solution is to install a marine transformer as mentioned by Bob. Rather expensive and heavy though. I haven't (yet) installed one myself. But then I'm not permanently connected to shore power.
But of course, as long as everything is in perfect order with the electrical system on both our own, and the boats around us, everything should be all right?!?Confused
 
Andreas


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S/Y Anne-Ma, Hanse 370 2007


Posted By: Brightside
Date Posted: 18 December 2008 at 22:32
Health Warning: These thoughts are pub talk but I hope they will help.

2030
On the Volvo 2030D the gearbox and thus saildrive & prop is electrically isolated from the engine. So electrically connecting to the engine block does not electrically connect to the prop.

A surveyor told me. Volvo bronze props from 2002 to 2004 are prone to de-zincification (turns pink) due to an incorrect balance of the metals used in the casting. Yachts from Swedish builders quietly had their props replaced by Volvo.

Anode Erosion.
I have found the 3 section anode ring to the Volvo prop dissolve faster than the anode screwed to the saildrive. After 2 months of ownership, alarmed at the rate that the 3 section anode dissolved (later found to be gone in 6 months) I fitted a third hull mounted anode close to the saildrive and electrically connected to the top of the gearbox.

WRT to AC leakage to earth current
Voltage can get on to the equipment's casing thus earth protection wire by either a short circuit (high voltage and high current) or by insulation breakdown or leakage by tracking across a wet surface (low voltage and low current). In the case of a short circuit the earth wire takes the heavy current, protecting the human by keeping the casing at earth potential (near zero volts) and the fuse on the live or the Earth Leakage Detector (aka RCD) trips thus cutting of the AC power. It is the low voltage low current scenario that causes electrolytic erosion.

Zinc Savers are two heavy current diodes connected in parallel and facing in opposite directions.   A positive or negative voltage of greater than 0.7v on the earth wire causes each diode to conduct in turn. Thus the current due to a voltage of 0.7v or greater (50v is considered a hazard) on the earth line is passed through the diode to the to the substation earth via the earth wire and the fuse or earth protection device trips removing the power.   When a voltage on the earth wire boatside of the diodes is less than 0.7v the diodes do not conduct, thus stopping the path to earth the substation earth and reducing the chance of a circuit being made to create galvanic corrosion.

Cathodes not Anodes.
In conventional electrics the current is said to flow from positive to negative. However in electronics, the true physics/chemistry is used ie. Electrons flowing from the negative (Cathode) to the positive (Anode) is used. The zinc that sacrifices itself is technically a Cathode not an anode, in M.G. McDuff's literature (UK supplier) you will see that they refer to Cathodic Protection

Regards
Mike

Re-worded description of diodes connection 20/12/08


Posted By: Netzerab
Date Posted: 27 December 2008 at 14:13
Originally posted by Rubato Rubato wrote:

Netzerab, I followed your explanation, most of us are well aware of the basics of electrolysis. However, at the end, where you mention that "A third alternative is to enable a local earth plane on board" I didn't understand the logic. Isn't this just moving the problem? It's an attempt to make another piece of metal the target of connecting the circuit, the same thing we try to do with the zincs. The same challenges exist, how to make that "other piece of metal" the target instead of the vital metal pieces of the boat.
 
Steve

The problem with shore power is the grounding wire. The grounding wire often has a DC potential due to several problems combined. Sometimes this potential can be much higher than the 1-1.5 volts that get eaten by the diodes in an galvanic isolator. In such cases the galvanic isolator is of little or no help. The problem is that you can't really know what the dc potential may be for a given day.

For those of us that do not have the money nor the space for an isolation transformer, there is another alternative called local earth.  It works like the earth in your home, but uses saltwater rather than the sand, clay or whatever is under your house. It is actually just a grounding wire connected to a piece of bare metal, usually copper, of a given area mounted under your boat and submerged at all times.

You can then safely cut the grounding wire to shore because you now has a local earth plane that would safely conduct any current trough the salt water and back to shore. The conducting capability of saltwater is excellent and it is a far better conductor than a questionable shore power grounding wire.

Since you no longer have a shore power grounding, you no longer have to be afraid of any dc potential causing electrolysis. There is no longer a permanent closed circuit between your boat and other shore power connected boats/shore power ground. But you still have a proper safety grounding that will save your life in case of a fault. The only difference is that a small part of the safety ground now uses salt water as an excellent conductor, but not conducting dc at alll times as before, just in case of a ground fault in some of your own electrical equipment, and then only ac. You are safe. Your boat are safe. Electrical faults in other boats no longer apply to you.

All you have to worry about is to keep your own electrical shore power system ship shape and preferably install a ground fault interceptor for instantly cutting off the ac current if there one day should be a ground fault aboard your boat.

Obviously this local earth depend 100% of the excellent conducting capabilities of salt water and the fact that the human body is not harmed from current flowing trough the water because of the very large difference in resistance between water and body. In fresh water the case is the opposite and even if your boat is still safe, a swimmer can easily be elecricuted. The low resistance path is suddenly the body. Current at low as 15-20mA is enough to kill a human.


Posted By: franko
Date Posted: 28 December 2008 at 11:27
Scary picture and, as one who has his boat in the water all winter with S.P. connected, I am getting nervous. However in 6 years have not had any problems. Does not mean I am complacent though, a fault on a neighbouring boat could cause problems.

On large yachts/ships we used to hang largish zinc anodes over the side when alongside. I might start to do that. Better than throwing away the partly eaten zincs each year maybe.

I wonder if a low current LED in the cable attaching such a zinc to the boat would give a visual indication of any problem.

Franko

(He He, Mike, it is M.G. Duff, not McDuff. They are commonly mistakenly called MCDUFF as the embossing on the anodes appears to spell that.)


Posted By: franko
Date Posted: 28 December 2008 at 17:20
Stephen,

Would like to know the brand of 'Tube Heaters' you refer to. I am looking for similar.

Thanks

Franko


Posted By: Abstinenz
Date Posted: 28 December 2008 at 19:07
Originally posted by RSchrHH RSchrHH wrote:

http://farm4.static.flickr.com/3145/2405261698_6266151f13.jpg?v= - These are the remains of the saildrive of my 370 after just five months in water.

It is completely unclear so far how this could possibly has happend.
 
Hanse Germany is not at all interested in solving the problem.
 
There is rumour that several other Hanses are affected.
 
Anyone here?

Hi,

a Luffe 4004 (model 2006) in our marina had the same problem after the first year in water. It was a volvo engine/drive. As written somewhere else in this thread, its the wirering/shore power grounding that's to blame.

/Steen


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Hanse 342#436


Posted By: colincooper
Date Posted: 28 December 2008 at 20:14

This isn't really a generic Hanse problem (unless you can show the wiring was defective).  A "standard" Hanse should be OK, although it would be nice if galvanic protection was "standard".  But no other boat manufacturers I know of do this as standard.  Discussion on this site is useful to help us protect our boats better - but I think you have a weak case if trying to show Hanse is liable - unless, there is a specific wiring fault on your boat.



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Colin (owner of Hilde - a 370)



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