Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 14-04-2016, 21:09   #1
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,339
Anodes and Air Conditioning

Most boats have anodes due to dissimilar under water metals in the drive line, or just to protect what is there. However, I have zero immersed metals when my twin outboards are retracted. No anodes, except on the motors.

Now I have installed AC. The through hulls and most of the piping is plastic, but the strainer and AC unit contains some metal parts. The factory (yes I called engineering) says follow ABYC, but I can't see where any of that referrers to this case (no submerged metals, only strainer and AC).

Thoughts? Mounting and external zinc seems awkward. If the only contact is bronze in the strainer and copper in the AC, does it matter?
__________________

__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Old 15-04-2016, 16:38   #2
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,339
Re: Anodes and Air Conditioning

No one? I could easily add an anode at a tee if needed. Is this ever done for plumbing? I know there are similar systems some times installed to reduce plumbing biofouling.

http://www.dtic.mil/dtic/tr/fulltext/u2/a557490.pdf

Clearly, unprotected copper pipe fouls less, but at the cost of corrosion:


And even the anode types makes a difference:
__________________

__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Old 17-04-2016, 17:17   #3
Registered User

Join Date: Mar 2011
Location: Caribbean
Boat: Oyster 66
Posts: 973
Re: Anodes and Air Conditioning

Quote:
Originally Posted by thinwater View Post
Most boats have anodes due to dissimilar under water metals in the drive line, or just to protect what is there. However, I have zero immersed metals when my twin outboards are retracted. No anodes, except on the motors.

Now I have installed AC. The through hulls and most of the piping is plastic, but the strainer and AC unit contains some metal parts. The factory (yes I called engineering) says follow ABYC, but I can't see where any of that referrers to this case (no submerged metals, only strainer and AC).

Thoughts? Mounting and external zinc seems awkward. If the only contact is bronze in the strainer and copper in the AC, does it matter?
An interesting question. Maybe if you look carefully the coil may be isolated. Have you measured resistance to ground? What's its alloy? Maybe something special?
__________________
poiu is offline   Reply With Quote
Old 17-04-2016, 18:00   #4
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,055
Re: Anodes and Air Conditioning

If you add say a pencil anode, it of course has to be connected electrically to the coil.


Sent from my iPad Pro using Cruisers Sailing Forum
__________________
a64pilot is offline   Reply With Quote
Old 18-04-2016, 20:41   #5
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,339
Re: Anodes and Air Conditioning

Quote:
Originally Posted by a64pilot View Post
If you add say a pencil anode, it of course has to be connected electrically to the coil.


Sent from my iPad Pro using Cruisers Sailing Forum

Obviously. The strainer is bonded. I question if it is needed, if the only metals are bronze and copper, and honestly, it is only the copper I am concerned about.

One option, I guess, is to watch the bronze for evidence of de-zinc.
__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Old 18-04-2016, 21:27   #6
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 4,815
Re: Anodes and Air Conditioning

Generally you'll have rubber or plastic tubing between the strainer and the copper coil. As such there is no current path to cause galvanic corrosion. For galvanic corrosion to occur both metals would need to be in physical contact with each other. No contact, no galvanic corrosion.

Anodes are not needed, generally for AC.

Bronze and copper are practically the same in the galvanic series, so no real galvanic action. Yellow brass on the other hand would dezinc.
__________________
sailorchic34 is offline   Reply With Quote
Old 19-04-2016, 17:33   #7
Writing Full-Time Since 2014
 
thinwater's Avatar

Join Date: Nov 2008
Location: Deale, MD
Boat: PDQ Altair, 32/34
Posts: 4,339
Re: Anodes and Air Conditioning

Quote:
Originally Posted by sailorchic34 View Post
Generally you'll have rubber or plastic tubing between the strainer and the copper coil. As such there is no current path to cause galvanic corrosion. For galvanic corrosion to occur both metals would need to be in physical contact with each other. No contact, no galvanic corrosion.

Anodes are not needed, generally for AC.

Bronze and copper are practically the same in the galvanic series, so no real galvanic action. Yellow brass on the other hand would dezinc.
One concern is stray current. The boat has a galvanic isolation, so in principle it is NOT connected through the shore power to other boats, only to a copper ground plate.
__________________

__________________
Gear Testing--Engineering--Sailing

Writing full-time since 2014.
Bookstore:http://sail-delmarva.blogspot.com/20...ook-store.html
thinwater is offline   Reply With Quote
Reply

Tags
air conditioning

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Air Conditioning run off Solar, batteries and Inverter ZipTie Electrical: Batteries, Generators & Solar 18 26-02-2016 09:15
Honda Generator and Air Conditioning sailor0516 Electrical: Batteries, Generators & Solar 18 06-02-2015 07:19
Genset and Air Conditioning for Bavaria 39 Cruiser Sinkers Monohull Sailboats 3 23-08-2010 23:02
Honda eu2000i and Air Conditioning marc Electrical: Batteries, Generators & Solar 2 21-02-2010 20:45



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 18:51.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.