anods unusual wearout


Gregory Dmitriev
 

Hi everybody,
I just have A54 out of water (since 03/03/21) today and see strange wear of anods:
- 2 of rudder - both dead 100%
- 1 of prop - dead 100%
- bowthruster - 1 dead 100% (starboard) BUT THE OTHER (port) ALMOST AS NEW ?!?!?! (both were not painted of course)

Any ideas ???

Normally they were wear for about 50% for the year in water.

Thanks,

Greg


 

Most likely the anode which was like new had a poor connection to the thruster because of a corroded bolt. Also, remember that when the bow thruster on your boat is raised, the anode is not in contact with seawater.

Best,

CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
www.AmelOwnersYachtSchool.com 
Yacht School Calendar: www.preparetocastoff.blogspot.com/p/calendar.html


   

On Mon, May 2, 2022, 11:15 Gregory Dmitriev <41greg.marine@...> wrote:
Hi everybody,
I just have A54 out of water (since 03/03/21) today and see strange wear of anods:
- 2 of rudder - both dead 100%
- 1 of prop - dead 100%
- bowthruster - 1 dead 100% (starboard) BUT THE OTHER (port) ALMOST AS NEW ?!?!?! (both were not painted of course)

Any ideas ???

Normally they were wear for about 50% for the year in water.

Thanks,

Greg


Gregory Dmitriev
 

Hi Bill,
both bowthruster anodes were in the same situation - raised. But only the starboard one got destroyed :(


Mark Erdos
 

 Hi Greg,


It sounds like you have developed a stray current. You probably want to take care of it promptly. 60 days is awfully quick to go through a set of zincs. It is not rocket science to locate the issue and source. But, having the right tools certainly helps. I recommend this gadget: https://www.seabis.com/

 

With best regards,

 

Mark

 

Skipper

Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - French Polynesia

www.creampuff.us

 




On 5/2/2022 5:15 AM, Gregory Dmitriev wrote:
Hi everybody,
I just have A54 out of water (since 03/03/21) today and see strange wear of anods:
- 2 of rudder - both dead 100%
- 1 of prop - dead 100%
- bowthruster - 1 dead 100% (starboard) BUT THE OTHER (port) ALMOST AS NEW ?!?!?! (both were not painted of course)

Any ideas ???

Normally they were wear for about 50% for the year in water.

Thanks,

Greg


Bill Kinney
 

Greg,

You have a serious stray current problem if your anodes are disappearing that quickly. This is very important to fix. Once your anodes are destroyed, the next thing to go will be other underwater metals. If there is enough current flow, very serious damage can occur very quickly (in weeks, not months!). Ordinary galvanic corrosion is a slow process.  Stray currents accelerate this by many orders of magnitude.

Somewhere on the boat you have an electrical connection between the battery and the bonding system that should not be there. Amel installed the "MAS" light to help find this problem.

The anode on the bowthruster that was not destroyed is not properly connected to the bonding system, but should be.  

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Maarten


Mike Longcor (SV Trilogy)
 

Hi All,

Reading Greg's original message, it would be one year and 60 days for those anodes. Maybe still a stray current issue as it is more wear than he usually sees, but also where the boat is kept, shore power hook up, and many other things can influence anode wear. Yearly check and replacement is pretty normal.

Anodes should be replaced when they are half their original size.

Greg, can you clarify what you mean by dead 100% ? Were they completely gone so who knows how long they lasted? Do you have a photo?

Cheers,
Mike Longcor
SV Trilogy SM23
NZ

 

On Thu, May 5, 2022, 12:18 AM Bill Kinney <cruisingconsulting@...> wrote:
Greg,

You have a serious stray current problem if your anodes are disappearing that quickly. This is very important to fix. Once your anodes are destroyed, the next thing to go will be other underwater metals. If there is enough current flow, very serious damage can occur very quickly (in weeks, not months!). Ordinary galvanic corrosion is a slow process.  Stray currents accelerate this by many orders of magnitude.

Somewhere on the boat you have an electrical connection between the battery and the bonding system that should not be there. Amel installed the "MAS" light to help find this problem.

The anode on the bowthruster that was not destroyed is not properly connected to the bonding system, but should be.  

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Maarten


Scott SV Tengah
 

No expert, but perhaps stray current in the marina or a negative/positive in the bonding system? The masse light should inform you of the presence of the latter, unless it's a 12v leak.

I will say that our anodes last a very very long time. The BT anodes are rarely replaced - same with the prop anode. And yes, I have confirmed that the rudder anode has sub 1ohm resistance to the bonding system/prop shaft.

--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Bill Kinney
 

Scott,

In the absence of a galvanic isolator or isolation transformer, stray currents can flow from boat to boat in a marina.  It would be unusual, but certainly not impossible, that they could dissolve anodes in a 2 months.  Every 54 I have been on has had a galvanic isolator, but I don't know if they were original equipment, or after-market modifications.

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Marteen


Scott SV Tengah
 

#69 did not have it installed. One of many reasons why I don't plug in much. ☺️


On Wed, May 4, 2022, 12:34 Bill Kinney <cruisingconsulting@...> wrote:
Scott,

In the absence of a galvanic isolator or isolation transformer, stray currents can flow from boat to boat in a marina.  It would be unusual, but certainly not impossible, that they could dissolve anodes in a 2 months.  Every 54 I have been on has had a galvanic isolator, but I don't know if they were original equipment, or after-market modifications.

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Marteen


--
Scott 
2007 A54 #69
SV Tengah
http://www.svtengah.com


Dominique Sery
 

Hello Scott, hello everyone,
When I bought my 54 there was no galvanic isolator installed, the anodes were quickly destroyed...  Since I installed one (Victron 32A) I no longer need to change the anodes every year. When I installed the galvanic isolator, I took the opportunity to measure the voltage between the quay ground and the boat ground (yellow-green wires), in a port in Greece. It was 500 mV. The Victron isolator cuts 600 mV according to the instructions. I was able to check it. And since then everything is fine. The galvanic isolator is much cheaper than an isolation transformer and should be considered by those who plug in regularly, it is very easy to install.
Dominique
A54#16


Mark Erdos
 

 Bill K, Not all Amels were made with the MAS system installed.

 

With best regards,

 

Mark

 

Skipper

Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - French Polynesia

www.creampuff.us

 


On 5/4/2022 2:18 AM, Bill Kinney wrote:
Greg,

You have a serious stray current problem if your anodes are disappearing that quickly. This is very important to fix. Once your anodes are destroyed, the next thing to go will be other underwater metals. If there is enough current flow, very serious damage can occur very quickly (in weeks, not months!). Ordinary galvanic corrosion is a slow process.  Stray currents accelerate this by many orders of magnitude.

Somewhere on the boat you have an electrical connection between the battery and the bonding system that should not be there. Amel installed the "MAS" light to help find this problem.

The anode on the bowthruster that was not destroyed is not properly connected to the bonding system, but should be.  

Bill Kinney
SM160, Harmonie
Simpson Bay, Sint Maarten