Do you need to zinc your bronze rudder hinges? - SailNet Community
LinkBack Thread Tools
post #1 of 3 Old 08-12-2012 Thread Starter
Closet Powerboater
MedSailor's Avatar
Join Date: Mar 2008
Location: Anacortes PNW
Posts: 3,925
Thanks: 298
Thanked 125 Times in 113 Posts
Rep Power: 10
Do you need to zinc your bronze rudder hinges?

I currently have an overly-exotic zinc system that came with the boat. I believe it is designed under the trade name "diver's nightmare!" and I've been the diver!

Next haul out I plan to re-do the whole thing. What I am wondering is if I really need to zinc my bronze rudder hinges? I don't believe in bonding every through hull and there are several silicone bronze through hulls that aren't directly connected to zinc and have been doing just fine. Why then, is there a huge plate zinc on my hull with a wire that attaches to the bronze hinges?

I know that a bronze prop can get eaten, thus the shaft collar zinc. Through hulls don't seem to get eaten. Is that because they're more isolated from the metals of the engine? The hinges seem to be more like the isolated through hulls to me.... Also, I don't recall seeing sacrificial zincs, or easy places designed into boats for said zincs, in the masses of boats in the yards.

Do you have zinc protecting your rudder hinges? Do I need it?


I have a sauna on my boat, therefore I win.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
MedSailor is offline  
Quote Quick Reply Share with Facebook
Sponsored Links
post #2 of 3 Old 08-12-2012
Senior Cruiser
sea_hunter's Avatar
Join Date: Jul 2000
Posts: 512
Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 17
I think it's a good idea. I usually sand them to metal leaving the bits where the paint is really stuck and prime with E2000 or equivalent epoxy primer then use a good quality bottom paint. The only thing I don't paint is the wheel (prop) and shaft.
sea_hunter is offline  
Quote Quick Reply Share with Facebook
post #3 of 3 Old 08-12-2012
Senior Member
RichH's Avatar
Join Date: Jul 2000
Location: Pennsylvania
Posts: 4,547
Thanks: 42
Thanked 257 Times in 243 Posts
Rep Power: 18
Re: Do you need to zinc your bronze rudder hinges?

You definitely need anodic protection for 'any' underwater metal ... either by a zinc affixed to the component or bonding it to a common 'zinc' through electrically intact wiring.

Formosa boats and other typical Taiwanese boats of that era usually had the bronze rudder pintles/hinges bonded to the rudder zinc through a copper 'strap' that was buried in the fiberglass of the aperture. You can check to see if this electrical protective circuit is still intact by using a voltmeter (VOM) between the cutless housing and the 'hinges' ...
AND the imbedded rudder frame if exposed. Since the cutless housing is usually connected to the boat's bonding system .... any zinc connected (and still electrically intact) should provide the pathway to 'any' so attached anode.
The problem here is not of 'over zinc' the boat ... or you will pick up a lot of hard growth such as barnacles on the prop, and other underwater metal running gear. For such a large boat you really ought to be using a calibrated 'reference' cell to measure the potential requierments of any large boat ... and apply the correct amount of anode surface area in accordance to the cell readings ... too little protection and you will begin to extract zinc from 'castings', etc., too much protection and all the underwater gear will become fouled with hard growth.

Corrosion reference cell/electrode: Corrosion Reference Electrode
RichH is online now  
Quote Quick Reply Share with Facebook

Quick Reply

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


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

Email Address:


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

Similar Threads
Thread Thread Starter Forum Replies Last Post
bronze rudder gudgeon help JESTER458 Gear & Maintenance 9 05-07-2010 07:10 AM
Tartan 30 Bronze Rudder shoe Levante33 Tartan 1 07-24-2009 11:08 AM
rudder zinc Newport41 Gear & Maintenance 2 12-13-2008 09:47 PM
Rudder Zinc Newport41 Newport 3 11-09-2008 09:50 PM
Zinc to protect bronze parts? brak Gear & Maintenance 3 05-27-2008 11:14 AM

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