Electro-Guard Cathodic Protection

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Joined
Dec 16, 2007
Messages
1,047
Location
U.S.A.
Vessel Name
Old School
Vessel Make
38' Trawler custom built by Hike Metal Products
When I bought the boat in 2008 it was delivered to a yard in Slidell, LA. I had several things done to it, installed a bow thruster, holding tank, and Electro-Guard cathodic protection. All of the zincs were removed and after the cathodic installation, the hull was painted. Back in the water about mid-October 2008. Last weekend I had her hauled out for a bottom cleaning, didn't really know what to expect, corrosion wise. I was pleasantly suprised that the bottom looked great, no corrosion visible after it was pressure washed. The prop, shaft, and bow thruster looked the same as when it was put in the water. Frankly, I expected this gizmo to be something akin to snake oil. My slip is located in fresh water (infrequently salt water), so no barnacles to deal with, just a nice coat of green slime that came right off. I would recommend this to anyone interested.
Mike
Old School
Baton Rouge, LA
 
Mike, since this system is suppose to protect your underwater metals as a zinc would do I am not sure how that translates to your bottom paint which is in no way affected by this system. The same thing can be accomplished with zincs for a whole lot less money and one less system on the boat to deal with. Corrosion issues are considerably less in fresh water than salt water and the environment your boat is sitting in also has a larger affect. If you are at a clean dock and your boats electrical system is in good shape, you should see NO corrosion in fresh water Chuck

-- Edited by Capn Chuck on Wednesday 12th of May 2010 10:56:55 AM
 
On the other hand, the Scorpius, a 1960s 90ft steel yacht I run has a similar system installed. The boat has been in sal****er almost all it's life, and when last surveyed including an extensive ultrasonic thickness test, the surveyor found the bottom plating to be mostly as good as new.* I don't know if any plating has been replaced in the past, but due to the readings being pretty much the same across the board, I'm guessing the system has worked as designed for the last 50 years.* I do run zincs on the prop shaft, but they seem to last several seasons.* So, for a metal boat, I highly recomend an active protection system.* Might also be good for boats with outdrives.............Arctic Traveller
 
S a l t w a t e r is a dirty word now??
hmm.gif
 
I saw that Keith and laughed to tears!!!! That is funny as all get out!!!
 
Keith wrote:

S a l t w a t e r is a dirty word now??
hmm.gif
Totally unintentional! I'm currently VERY sleep deprived.* Working 15hr days, 7 days a week on the Princess Cathleen oil recovery project in Juneau.* The boat sank in 1952 with full tanks of bunker fuel which have been leaking.* I'm working on the oil spill recovery team containing what little oil escapes when the divers make connections to the tanks.* Pay is outstanding, but there are not enough hours in the day to sleep.........zzzzzzzzzz

*


-- Edited by Arctic Traveller on Saturday 15th of May 2010 06:45:02 PM
 
Arctic Traveller wrote:I don't know if any plating has been replaced in the past, but due to the readings being pretty much the same across the board, I'm guessing the system has worked as designed for the last 50 years.*

Most steel boats rot out from the inside. Cathodic protection is there to protect the props and other fittings.

Except for a few very rare instances (waterline and around rivets), I have never come across pitting and hull corrosion on the external skin. That is why you audiogauge the things, because if you could see the pitting from the outside you wouldn't need to audiogauge.

And to conclude, most of the pitting internally comes from standing water or localized "cells" that originate beneath mud or other contaminants that are not effected by the cathodic protection system.
 
Rick,* point well taken. And, your correct that keeping the bilges maintained is critical.* Scorpius has an epoxy paint job in all voids, and sparkles more in some voids than the topsides.* Very expensive and time consuming to do, but quite worth while............Arctic Traveller

-- Edited by Arctic Traveller on Monday 17th of May 2010 06:40:45 PM
 
If one had a VERY expensive CPP type propeller then it would make a lot of sense to protect the investment with the latest (at least the last 40 years or so) and greatest technology: The famous impressed current protection system.

If the large tankers and other commercial boats are using it then there is a good reason for it = MONEY.

When these systems trickle down to our level and is affordable, then I will definitely invest in one. I hope one will be available next year when I float my boat...
 
We have that system on our Nova Sundeck trawler and it has worked perfectly for the 12 years we have owned the boat. We have two plate zincs mounted on the transom and they do the job.
 
We have two plate zincs mounted on the transom and they do the job.
Ralph: Aren't those two zincs just part of your bonding system?
 
OK, they are tied in - but are the zincs really required after installing a cathodic protection system?
I could be dead wrong here but I think Ancora is confusing a standard bonding system with an Electro- Guard cathodic protection system that the PO was referring to.
 
The two transom zincs are tied into everything on board. They work in conjuction with the Electro-Guard system. When the zincs deteriorate to a point where I cannot keep the Electro-Guard meter in the "green" thay must be changed. I get about six months out of them.
 
The two transom zincs are tied into everything on board. They work in conjuction with the Electro-Guard system..

My apologies! Your first post, relative to the Electro-Guard system, made no mention of a meter which made it sound like my boat's bonding system. (Everything is connected by bonding wires which run to a large zinc plate on the hull stern.) :peace:
 
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