Replacing Zincs Too Frequently

[Knot-Enuff]

I have had a problem on my boat with having to replace the zincs in just four months. Done this twice since January. I don't believe it is just my boat because my neighbors are also complaining. Some say it's because the marina has electrical issues, and some say it is water conditions. My question is that one neighbor braggs because his boat does not have any zincs. It is equipted with some sort of grounding or isolation system so as not to need zincs. Is anyone familiar with what they are speaking of and is anyone using this. Sounds like it could be a good thing. Thanks for your comments.

 

[DavidM]

There are three things that come to mind that cause more rapid than (whatever is) normal zinc useage:

1. Internal DC fault on your boat to ground. Often bilge pump wiring.

2. External DC fault on another boat that affects you through the shore power ground. A galvanic isolator (good) or an isolation transformer (best) can prevent this.

3. Your neighbor with no zincs turning up his protection system too high which then corrodes your zincs!!! As you can imaging I don't think much of those systems.

David

 

[FF]

If you travel from marina to marina an isolation transformer , and a quality marine battery charger are good insurance.

IF the marina has electrical problems , there are many methods of measuring and isolating the problem.

 

[fstbttms]

I have had a problem on my boat with having to replace the zincs in just four months. Done this twice since January. ...some say it is water conditions.

I'd like to know what "water conditions" these geniuses are referring to.

 

[Art]

Howdy - I've nothing special to add at this time; simply tagging in here so I can be appraised when posts occur to this thread. Always interested to follow discussions re anode/diode/corrosion/galvanization/electrical-transfer/hot-cool harbors... etc, etc.

My current boat's lucky - she sits in fresh water in a very "cool" harbor. That said: I've got an offer on a boat that if purchased will be docked in a saltwater harbor off SF Bay. The boat currently in fresh water used to be in same Bay harbor and I needed to replace zincs in 6 to 9 month increments. When I again dock a boat near SF Bay I’ll be interested to learn any new ways to best extend anode life in salt water while still providing the diodes good protection.

Carry On!

Happy Boating Daze!! - Art

 

[Phil Fill]

So have you inquired how often other boats in the marina, but NOT around you change their zincs. Is it a local or marina wide? Your marina should have a good idea how long zincs should last, and if your are not ask them to check the dock and the water for stray electricity. I have a diver check/clean the hull ever three months just of make sure nothing has change.

Also the boat with out zincs maybe using you zincs for protection? Causing the zincs on surrounding boat zincs to be used faster. I would assume the other boats and yours has a galvanic isolator protects the boat when plug into shore power. An isolator allows current to flow out of the boat, but NOT in using the green ground AC electrical wire which is connect to the green zinc loop wire. If not you should install one, and if you do have one make sure its working properly.

The Galvonic Isolator and the zinc protect loop is one of the important systems on the boat but the least understaood. I test for stray electricity most months, especially if there is a new boat close to us.

If the zincs re going to fast you could added additional/bigger zincs and/or change to aluminum. The last time we pulled I had a big Divers Dream zinc added in the bow to protect the bow thruster as the small clam shell had to be replace every 6 months. Also some boat hang a big grouper zinc over the side for additonal protection.

Anyway ask around and see what the marina norm is!

 

[fstbttms]

I've got an offer on a boat that if purchased will be docked in a saltwater harbor off SF Bay.

Anyway ask around and see what the marina norm is!

Art- what marina does the boat live in?

 

[Art]

Art- what marina does the boat live in?

fb - When I keep a boat near SF Bay it's in Lowries or Loch Lomond.

 

[fstbttms]

fb - When I keep a boat near SF Bay it's in Lowries or Loch Lomond.

Oh. I don't work in either marina, so I can't offer an opinion on zinc usage in either.

 

[Art]

Oh. I don't work in either marina, so I can't offer an opinion on zinc usage in either.

fb... lots o' boats! Marina officials easy to deal with. Ya ever try marketing in either?

 

[fstbttms]

Oh, I have worked in both, on occasion. And would do now if it was a job like a feathering prop install (something I specialize in.) But I don't do hull cleaning in Marin. Too far to go. Strictly East Bay now.

 

[Scary]

Fresh Water Anodes

Howdy - I've nothing special to add at this time; simply tagging in here so I can be appraised when posts occur to this thread. Always interested to follow discussions re anode/diode/corrosion/galvanization/electrical-transfer/hot-cool harbors... etc, etc.

My current boat's lucky - she sits in fresh water in a very "cool" harbor. That said: I've got an offer on a boat that if purchased will be docked in a saltwater harbor off SF Bay. The boat currently in fresh water used to be in same Bay harbor and I needed to replace zincs in 6 to 9 month increments. When I again dock a boat near SF Bay I’ll be interested to learn any new ways to best extend anode life in salt water while still providing the diodes good protection.

Carry On!

Happy Boating Daze!! - Art

Fresh water anodes should be aluminum or preferably magnesium. Zink anodes will not work as well and in fact may give you a false sense of security as often they don't work at all. In brackish water the nod goes to aluminum. The West Marine Catalog has a good explanation.

 

[fstbttms]