Extra Zinc Anode - SailNet Community
 
LinkBack Thread Tools
post #1 of 5 Old 08-25-2010 Thread Starter
2nd mate
 
Join Date: Aug 2009
Location: Belgium
Posts: 42
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
 
Extra Zinc Anode

Hello,

Small question here:

In adjunction to my zinc anode on the prop shaft, i would like to install an extra zinc anode on a cable. This to make the prop zinc last longer.

One end of the cable: the extra zinc anode hanging in in the water.
Other end the cable: hangs on the SS lifeline around the boat (with a SS carabiner).

I would then electrically connect a stanchion nearby to the propshaft (under deck).

Prior to sailing, i can easily remove this extra zinc anode and stow it away.

My propshaft is SS with a zinc and bronze prop.
Green-yellow cable of AC-shorepower is not connected to negative DC.

Is there anything i have forgotten why i should not electrically connect propshaft to the life lines?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
bartvdv is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
Advertisement
 
post #2 of 5 Old 08-25-2010
Senior Member
 
mitiempo's Avatar
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,501
Thanks: 0
Thanked 96 Times in 87 Posts
Rep Power: 8
   
To be effective the hanging zinc should be within 12" to 18" of what you are trying to protect.

As far as the shorepower ground it should be connected to the DC ground for safety. A galvanic isolator will solve possible corrosion problems - $99 from Yandina.

Brian
Living aboard in Victoria Harbour
mitiempo is offline  
Quote Quick Reply Share with Facebook
post #3 of 5 Old 08-26-2010
I don't discuss my member
 
Fstbttms's Avatar
 
Join Date: Feb 2003
Location: Under a boat, in a marina, in the San Francisco Bay
Posts: 2,184
Thanks: 5
Thanked 26 Times in 26 Posts
Rep Power: 13
 
Quote:
Originally Posted by mitiempo View Post
To be effective the hanging zinc should be within 12" to 18" of what you are trying to protect.
On what do you base this claim?
Fstbttms is offline  
Quote Quick Reply Share with Facebook
post #4 of 5 Old 08-26-2010
Telstar 28
 
sailingdog's Avatar
 
Join Date: Mar 2006
Location: New England
Posts: 43,290
Thanks: 0
Thanked 15 Times in 12 Posts
Rep Power: 14
         
Fstbttms—

Given the fairly low voltage differentials involved, having the zinc any significant distance away will render it ineffective. Especially if that distance is through something like stainless steel rigging, which has about 33x the resistance of copper wire IIRC. Also, I'd point out that the connections that Bart is planning to use are low-contact-area, high-resistance connections. From his OP:

Quote:
One end of the cable: the extra zinc anode hanging in in the water.
Other end the cable: hangs on the SS lifeline around the boat (with a SS carabiner).

I would then electrically connect a stanchion nearby to the propshaft (under deck).
A stainless steel carabiner clipped to a stainless steel lifeline is going to be a really lousy connection... he'd probably do better by clamping battery jumper cables made from tinned wire to the shrouds...

Sailingdog

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Telstar 28
New England

You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

If you're new to the Sailnet Forums... please read this
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
.

Still—DON'T READ THAT POST AGAIN.
sailingdog is offline  
Quote Quick Reply Share with Facebook
post #5 of 5 Old 08-26-2010
Senior Member
 
mitiempo's Avatar
 
Join Date: Sep 2008
Location: Victoria B.C. Canada
Posts: 7,501
Thanks: 0
Thanked 96 Times in 87 Posts
Rep Power: 8
   
Yes proximity is important. One neighbor was replacing his shaft zincs quite often. He used a zinc fish over the side but maybe 10 or 12 feet from his stern and while the shaft zinc dissolved quickly his fish did not. Moving it closer solved the problem. If closer is better closest is best. Also like dog posted a clip to a stainless lifeline is not very effective. The fish should be on a good gauge of wire like #6 and the boat end should ideally have a good crimped ring fitting and be attached firmly to a good ground.
The green shorepower earth should be connected to the ship's ground for safety. If there is a fault the current has to go somewhere and this gives it a safe path. You say there is no connection on your boat? That would mean no battery charger where AC and DC reside in close proximity and AC can leak across to the DC side in some cases and if there is a fault. Remember that many chargers have a case ground that should go to DC as well as the DC output. A fault in that charger can make the DC system hot.
A galvanic isolator is also a must I believe. It will eliminate the currents that cause zincs to dissolve quickly but still pass current when there is a high voltage fault. It will not however protect your boat from stray current coming from other power sources like dock issues.

Brian
Living aboard in Victoria Harbour
mitiempo is offline  
Quote Quick Reply Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now



In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.


User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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 On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome