Zincs

[Rex Delay]

I used to put 2 zincs on my shaft and they would be in good condition after 2 years when I regularly haul. Had to do a quicky haul today and noticed one of the zincs is quite worn after only a couple of months. Not much has changed except my new (steel) neighbor. If I add another (third) zinc before putting it back in the water in the morning, could this cause issues from over protecting?

[Ike]

Don't add another anode. If your anodes are lasting 2 years without deterioration then you are over-protecting your boat. (yes you can overprotect) You need to find out what is causing the problem. It may be your new neighbor and it may not. I suggest you get a marine electrician to chek for stray currents in the water, and if they find some, then track down where they are coming from. It's not only affecting you, it's affecting everyone around you as well.

[bstreep]

As Ike said, can CAN overprotect - and that's bad too.

[Mark Johnson]

Originally Posted by Ike

Don't add another anode. If your anodes are lasting 2 years without deterioration then you are over-protecting your boat. (yes you can overprotect) You need to find out what is causing the problem. It may be your new neighbor and it may not. I suggest you get a marine electrician to chek for stray currents in the water, and if they find some, then track down where they are coming from. It's not only affecting you, it's affecting everyone around you as well.

AMEN! I first stayed in the marina from electrical hell! I had no rig, interior, or electrical system, at the time. (Boat was still in construction). With NO connection to the dock, my Zincs would go away in ONE WEEK! It was getting expensive.

I would also get shocked if I walked the concrete docks barefoot, or get a BIG one if I was getting out of the water and touched a dock cleat!

When I pointed out the exposed feed wires against the dock's primary bolts holding it together... I was asked to leave!

It could be the dock... OR the guy next door. It can even be any boat close buy, using an "automotive type" battery charger. They are notorious...

I agree that if your two zincs are lasting two years, you are over Zinced and need just one. In this case, as always, watch it when you move to a new marina, within the marina, or get a new neighbor. If it's behavior changes, figure out why! M.

[Rex Delay]

I pulled the boat in March, about one year after the last bottom job and new zincs. The zinc nearest the stuffing box was in good shape, the one by the strut was sot, replaced it in March, hauled again yesterday to re-pitch the new prop and the month old zinc was 25% gone already. Put on another in its place but cannot figure out what has changed. Most of the boats near me are not even plugged in and why one zinc being attacked and not the other?

[Ike]

What you have is stray current corrosion. The current is entering your boat by one of the other fittings and leaving by the one at the strut. That is why that zinc is disappearing. The stray current is coming from some where. There are three choices:
Your boat
Some other boat
The shore power system is leaking current.

For your boat you need to ask yourself has there been any change to the electrical (DC or AC), or has any service been done on the electrical system recently. If the answer is yes then your system needs looking at. The most common is something was installed and there is a ground fault. Everything may work fine, but the device is connected to ground where it shouldn't be. The other most common is during routine servicing something got hooked up wrong.

If you have eliminated your boat then you need to start looking elsewhere. This requires doing measurements of current in the water and isolating where it is coming from. This usually involves slowly unhooking every boat in the marina until the current stops. The last one unhooked is the culprit.

On the other hand, if all the boats are unplugged and the current is still flowing then the shore power system is at fault, and more than likely has a ground fault (usually a connection between the hot side (black wire) and the grounding wire (green wire) ) If no ground fault then they need to check for a reverse polarity. You can get a device for a few bucks at any hardware store that you just plug into a regular AC outlet that will tell you if there is reverse polarity.

[Rex Delay]

Nothing has changed on my boat so in the morning I will begin the search of the marina. For other boats in the marina, do I have to do every single one or just the boats within a certain radius? There are a couple of hundred if I have to do every one! I have been in this marina for over 10 yrs and this is the first time I have encountered this.

[Ike]

The first thing you need to do is check for current in the water. That requires a meter and a special silver-silver diode probe to put in the water. If you don't have a way to do that then you've skipped the first and most important step. Once you have done that then start unhooking boats, moving outward from your boat (make sure you unhook your boat from shore power first) You keep moving outward until the current on the meter stops. Obviously this requires two people.