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Electrolysis and Galvanic Action in Practice and Theory

Oct 19, 2017
6,879
O'Day 19 Littleton, NH
I had hoped to be able to develop this or a related thread into an organized reference to the issues around marine galvanic action. Not having a good understanding myself, it seems the start in chaos, like the genesis of the Cosmos, is unavoidable while we collect the pieces we know and then begin to bring it all into order.

Let's start, at this point, by connecting suggestions for categories to work within. Boaters have obvious concerns because of the nature of the construction of modern boats, the environment we play in and the products and technology availible for dealing with the issues.

I suggest we break this out broadly, into
  1. Definitions
  2. Physics/Chemistry
  3. Environment
  4. The boat
  5. Technology and products
Each category needs to be broken down further. There are plenty of chemical and material engineers on SBO. I'm more than happy to defer to the experts.

I expect the will be various parts that will lead naturally to divergent discussions. No problem. Some subjects need more depth, we'll make an effort to bring it back in to the course.

-Will (Dragonfly)
 

TomY

Alden Forum Moderator
Jun 22, 2004
2,648
Alden 38' Challenger yawl Rockport Harbor
While I seem immune to severe galvanic corrosion on my boat, at home is a different story. I'm replacing an electric water heater that I installed new 12 to 15 years ago. I've replaced several in my biz and homes. I've never replaced the typical anode inside a household water heater(I'm not a plumber by trade).

Supposedly they should be changed on 1 to 5 year intervals, depending upon who you ask(on google). Would a fresh anode always in the tank, make it last longer? Probably,... but maybe not,...according to online wisdom.

Most steel tanks fail (there are some life time tanks at 3 X the cost), in much the same way. They spring a small leak, which grows if you don't notice it. I've read they can take off like a rocket, but I've never seen that.

Failure rates may be conditioned on water quality. Water softeners add salt and shorten life, etc(we're on city water which is pretty pristine fed from a high clean reservoir).

I got the high average (12-15yr) on the last one.

I know this doesn't help, Will. :)
 

dLj

.
Mar 23, 2017
1,776
Belliure 41 Snug Harbor, Lake Champlain
  1. Definitions
  2. Physics/Chemistry
  3. Environment
  4. The boat
  5. Technology and products
Nice - I think I'd rather see something like:

1 Basic corrosion theory
2 Metals in the marine environment
3 Dissimilar metals corrosion
4 The water environment - ocean vs fresh water
5 Protecting your boat
6 Stray current corrosion
7 Applied theory or the practical realities
8 Myths and misconceptions

Something like that. We would need several contributors.

dj
 
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dLj

.
Mar 23, 2017
1,776
Belliure 41 Snug Harbor, Lake Champlain
While I seem immune to severe galvanic corrosion on my boat, at home is a different story. I'm replacing an electric water heater that I installed new 12 to 15 years ago. I've replaced several in my biz and homes. I've never replaced the typical anode inside a household water heater(I'm not a plumber by trade).

Supposedly they should be changed on 1 to 5 year intervals, depending upon who you ask(on google). Would a fresh anode always in the tank, make it last longer? Probably,... but maybe not,...according to online wisdom.

Most steel tanks fail (there are some life time tanks at 3 X the cost), in much the same way. They spring a small leak, which grows if you don't notice it. I've read they can take off like a rocket, but I've never seen that.

Failure rates may be conditioned on water quality. Water softeners add salt and shorten life, etc(we're on city water which is pretty pristine fed from a high clean reservoir).

I got the high average (12-15yr) on the last one.

I know this doesn't help, Will. :)
@TomY So this is an example that makes me hesitant to write a thread such as @Will Gilmore has suggested. In your case of the water heater, you ask if changing out anodes on some periodic schedule would be beneficial. Generally speaking the answer is yes. But, it depends. It depends upon your water chemistry and why in your particular situation do your water heaters start leaking. Do you get deposits in your tank? If so then changing the anode may not have a major effect. There are numerous other things that can contribute to your specific water heater popping a leak. Unless I could examine your specific water heater and the leak it had, I can't give you advice that is useful.

This is a great example - this kind of dilemma is faced when writing on the topic of corrosion. One could write general guidelines, like it's better to change your anodes, but then it doesn't help someone who has holes due to MIC (microbiologically induced corrosion), for example. In that case changing anodes does nothing.

dj
 
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Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
Nice - I think I'd rather see something like:

1 Basic corrosion theory
2 Metals in the marine environment
3 Dissimilar metals corrosion
4 The water environment - ocean vs fresh water
5 Protecting your boat
6 Stray current corrosion
7 Applied theory or the practical realities
8 Myths and misconceptions

Something like that. We would need several contributors.

dj
Why reinvent the wheel?

How about a book club approach. Pick a book on the subject, for corrosion I'd suggest Collier's book, and each week read a chapter. Then have a discussion on the chapter. Time limit the discussion for each chapter to a week, let anyone read the posts, but you must have read the chapter to post a question or comment.
 

dLj

.
Mar 23, 2017
1,776
Belliure 41 Snug Harbor, Lake Champlain
Why reinvent the wheel?

How about a book club approach. Pick a book on the subject, for corrosion I'd suggest Collier's book, and each week read a chapter. Then have a discussion on the chapter. Time limit the discussion for each chapter to a week, let anyone read the posts, but you must have read the chapter to post a question or comment.
This is a very interesting idea. I'm not sure with this approach how one handles outside sources when discussing the chapter? I got rather frustrated listening to Google search babble. But, I would like to provide critical comments based on established reference sources.

dj
 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
This is a very interesting idea. I'm not sure with this approach how one handles outside sources when discussing the chapter? I got rather frustrated listening to Google search babble. But, I would like to provide critical comments based on established reference sources.

dj
The point that not all sources of information are equal and nor do they need to be treated equally is well made. If someone were to cite a source of dubious quality, then it should be fair for the rest of the group to call that out. If an additional reference is made, that reference should be available to all. That shouldn't be a big issue except perhaps for an academic paper.

If anyone suggests that a small mobile cold-fusion reactor would be a good energy source for impressed current corrosion while providing power for the boat and the undeveloped world, they could expect to be robustly chastised and cast adrift in a small boat with said power source as the only means of propulsion. ;)
 
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Feb 6, 1998
11,436
Canadian Sailcraft 36T Casco Bay, ME
I'd suggest reading Evertt Collier's book The Boatowner's Guide to Corrosion. It is well written and covers the myriad kinds of corrosion we run into on our boats. @Maine Sail recommended it to me several years ago when I began working on a steel boat that had corrosion issues.
Unless everyone here has read that book, as the "101" level per-requisite, and they comprehend it, it will be very difficult if not impossible to have a good conversation about this. In every instance of this type of discussion I have seen on-line, it just turns into a thread full of old-wives-tales and often times gross levels of misinformation.

I will just say this about corrosion on boats;

- In the vast majority (mid 90's or higher) of corrosion cases we are called in on, the problem is found to be originating on-board the owners vessel.

- It is almost always, DC in nature, not AC related.

- In every instance the owner was 150% positive, and quite adamant, it was someone else's boat causing the issue.




This is why it is so hard to actually discuss marine corrosion.... If we really want to do this everyone should get a copy or Colliers book...
 

dLj

.
Mar 23, 2017
1,776
Belliure 41 Snug Harbor, Lake Champlain
If an additional reference is made, that reference should be available to all. That shouldn't be a big issue except perhaps for an academic paper.
Yes, and reference books that many may not have not access to. I guess small excerpts can be put here citing the reference? I'm also thinking of standards. There are excellent consensus standards such as ASTM, NACE, and ISO which could have relevance. I think you can quote small sections of those with the reference to what they are without copyright infringement. Can't expect everyone to be able to get all the above reasonably...

dj
 
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Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
Yes, and reference books that many may not have not access to. I guess small excerpts can be put here citing the reference? I'm also thinking of standards. There are excellent consensus standards such as ASTM, NACE, and ISO which could have relevance. I think you can quote small sections of those with the reference to what they are without copyright infringement. Can't expect everyone to be able to get all the above reasonably...

dj
There is a fair use standard. If the citation is given and a paragraph or a table is used, I don't the copyright police will get after us. The other issue may be the background necessary to understand the academic reference.
 
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dLj

.
Mar 23, 2017
1,776
Belliure 41 Snug Harbor, Lake Champlain
If we really want to do this everyone should get a copy or Colliers book...
That was exactly the proposal. I am completely in agreement with everything you've just posted.

The proposal was that each person posting must have the Colliers book, and have read the chapter under discussion. Now, how do we know if that's the case? I don't know. Do we talk to the moderators and see if these threads can be monitored and errant posts simply be removed? Do we establish a "board of directors" where if that board agrees that a post should be deleted it gets taken out?

I really have no good idea of how to do this.

dj
 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
The proposal was that each person posting must have the Colliers book, and have read the chapter under discussion. Now, how do we know if that's the case? I don't know. Do we talk to the moderators and see if these threads can be monitored and errant posts simply be removed? Do we establish a "board of directors" where if that board agrees that a post should be deleted it gets taken out?
If folks buy into the idea, then social pressure can help keep folks focused. If some one who has not read the material asks a question or makes an off topic comment, it will be quite apparent. We might even propose a structure to questions, "On page XXX, Collier says "YYY"" I don't get it, help me understand how this works" It will be quite clear the person has read it. Likewise, if the current chapter is on crevice corrosion, a question like, "What's crevice corrosion?" would certainly indicate the person has not done his/her homework.

It would be good to have some one be a point person who took responsibility for helping the forum to remain on task and to perhaps privately advise folks of the expectations.

Unless everyone here has read that book, as the "101" level per-requisite, and they comprehend it,
That would be the point of the forum, to help folks come to understand and comprehend the issues. I used to play a chemist in HS and college and some of the book is still a little dense. Some of our resident chemists, engineers, and corrosion experts would be called up to help clarify issues in a structured manner.

Corrosion issues come up a lot, something like this might help educate the masses.
 
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dLj

.
Mar 23, 2017
1,776
Belliure 41 Snug Harbor, Lake Champlain
I've ordered my copy of Colliers. I'm also sitting on a plane heading out for work and won't be back home for a week. By then, the book should be at my house - let the fun begin! LOL

@Maine Sail, @dlochner, @Will Gilmore, @JamesG161 - you all want to try this? Anybody else wish to read/buy/rent the Colliers book suggested and join in this discussion?

dj
 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
@Maine Sail, @dlochner, @Will Gilmore, @JamesG161 - you all want to try this? Anybody else wish to read/buy/rent the Colliers book suggested and join in this discussion?
Yep, I'm up for this, although I won't buy another copy of the book. ;)

While I sort of started this idea of a book club/self study group, I'll decline to take any role in organizing it. We'll be leaving in early June on our grand adventure from Lake Ontario, out the St Lawrence, and then we'll turn right. Once we get going internet access will be spotty and relatively expensive.

Perhaps we should let @Phil Herring know what we're thinking. :)
 
Oct 19, 2017
6,879
O'Day 19 Littleton, NH
I'm game for all this. I do, however, think a little leeway on being up to date with the reading should be given. If I read a post about a section in the book, I might not have had a chance to catch up on the reading, but a serious question or need for clarification may have me wanting to ask a before the subject moves on without my being able to get an answer. I certainly wouldn't mind someone new coming into, say, page 12 in the thread and asking a reasonable question that may have been covered on page 6. We would just point that out or someone would simply answer the question. No need to be overly formal.

As far as citing published technical material, I don't think the copyright laws were meant to hinder open discussion of such material. As long as we don't suggest someone else's work is our own, no need to worry about plagiarism either. No one's trying to make money off someone else's work here.

Perhaps another good purpose for this thread is to help compare and assess online material with regard to this subject. Most people who pop in to read this, because it came up on a Google search, aren't going to go out and buy a book. I'm interested in helping to building something both informative and practical. I know this isn't the place for anyone to earn their PhD, but it should offer more than just some suggestions of what steps to take to protect a boat none of us has ever seen.

As far as the need for moderation, SBO generally does a great job and we have no problem letting someone know when they are getting out of control. I don't mind taking point on helping someone understand the guidelines. Just keep in mind, we are an open forum and there will be participation that not everyone cares to read. We will have to put up with some of that. I agree that we should try to keep it limited and on course.

How about starting off with some suggestions on what to find a cheap used copy of Collier's book.

After that, I suggest starting each section with a bold, large type font that describes the limits of the discussion to follow. Try to keep in mind that the these posts will pop up in Google, so be clear about what we are talking about.

-Will (Dragonfly)
 
Oct 19, 2017
6,879
O'Day 19 Littleton, NH
1 Basic corrosion theory
2 Metals in the marine environment
3 Dissimilar metals corrosion
4 The water environment - ocean vs fresh water
5 Protecting your boat
6 Stray current corrosion
7 Applied theory or the practical realities
8 Myths and misconceptions
Is everyone good with starting the structure for this thread like this? Anyone have anything to add? Maybe a section on common problems a sailor might see: prop corrosion, engine parts, battery draw, whatever. I'm not, yet familiar enough with this stuff to be comprehensive.

-Will (Dragonfly)
 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
How about starting off with some suggestions on what to find a cheap used copy of Collier's book.
Check the used book stores. Amazon has used versions for about $12 including shipping.

 
Jan 11, 2014
7,738
Sabre 362 113 Fair Haven, NY
Is everyone good with starting the structure for this thread like this? Anyone have anything to add? Maybe a section on common problems a sailor might see: prop corrosion, engine parts, battery draw, whatever. I'm not, yet familiar enough with this stuff to be comprehensive.
Collier's book starts with chapters on very basic stuff. I think following his book, chapter by chapter would be best.

Just keep in mind, we are an open forum and there will be participation that not everyone cares to read. We will have to put up with some of that. I agree that we should try to keep it limited and on course.
Well, if they don't care to read, then so be it. Just don't jump in with an opinion if you haven't done the homework.

I do, however, think a little leeway on being up to date with the reading should be given. If I read a post about a section in the book, I might not have had a chance to catch up on the reading, but a serious question or need for clarification may have me wanting to ask a before the subject moves on without my being able to get an answer. I certainly wouldn't mind someone new coming into, say, page 12 in the thread and asking a reasonable question that may have been covered on page 6. We would just point that out or someone would simply answer the question. No need to be overly formal.
Depending on how the forum is organized, this may or may not be a problem. Each thread needs to be focused on a particular chapter. It's OK if some one comes late to the party and posts a question on Chapter 1 when the rest of the group is on Chapter 2. However, if questions on Chapter 1 are posted on the Chapter 2 thread, the whole project will devolve into chaos.

Earlier I said I could not commit to a long term commitment to lead the forum, I can commit to helping structure it to keep it on topic, focused and helpful.

If SBO goes along with this, it would be an interesting experiment in a crowd sourced study group.
 
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