SailNet Community - Reply to Topic
Thread: How important is it to change zincs in fresh water? Reply to Thread
Send Trackbacks to (Separate multiple URLs with spaces) :
Post Icons
You may choose an icon for your message from the following list:

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.

  Additional Options
Miscellaneous Options

Click here to view the posting rules you are bound to when clicking the
'Submit Reply' button below

  Topic Review (Newest First)
06-18-2007 10:27 PM
Originally Posted by RickBowman
Who would install aluminum parts below the waterline on a sailboat?
Ummm.. lots of new boats are equipped with saildrives, and the saildrive housing is generally aluminum...
06-18-2007 10:05 PM
sailingdog Labatt-

Galvanic corrosion is still a problem in freshwater. However, zincs made of zinc are not generally reactive enough to provide your boat sufficient protection in fresh water. Fresh water boats should have either aluminum (brackish water usually) or magnesium (pure fresh water) zincs. If you've got zinc-alloy zincs, they can often not be affected while the aluminum parts of your boat get attacked.

You should also keep a notebook on the boat, preferably in the maintenance log, that lists the important consumables and what their size/part numbers are, so you don't have to haul the boat to figure it out. Oil filters, fuel filters, impellers, zincs, clevis pins, shear pins, and other things like that should be on the list IMHO. Also, might want to list various fuses and what amperage is used for what circuits.
06-18-2007 09:22 PM
Originally Posted by labatt
Is it worth the expense of hauling her to replace the zincs? Will they "coat themselves" with zinc oxide so quickly that they are useless?
Haul the boat to replace anodes?!!! There has got to be a diver around that can do it much more quickly and cheaply.
06-18-2007 09:09 PM
How important is it to change zincs in fresh water?

In another thread I just learned that, when in fresh water, you need to replace your zinc sacrificial anodes with magnesium. Since I kind of hijacked that thread I figured I would start a new one. Our boat entered fresh water Mid-May and will be hauled in October (so figure 5 1/2 months in fresh water) and we'll probably be bringing her back to salt water next year.

Is it worth the expense of hauling her to replace the zincs? Will they "coat themselves" with zinc oxide so quickly that they are useless? I'm concerned that I'll have to haul her twice - first to measure the prop shaft zinc and the hull plate zinc - and second to actually replace them once I find ones that fit. Even hauling her once is a few hundred $$$'s.

I'm assuming that what will happen is that they will become coated with zinc oxide, becoming useless for their purpose, which will allow other metals to give up their electrons faster than the zinc? Is galvanic corrosion still a risk in fresh water?

If I need to do it, I need to do it...


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

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