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Discussion Starter #1
Hey All,

I'm a new owner of a 2008 Beneteau 343, and just recently I had my bottom dove on for the first time, and this is what my diver found. Keep in mind, I only brought the boat home to my dock on/around Feb 10, 2009...and its only 1.5 months later:



I think this is my new zinc from west marine (but not sure):





Anyone know what could be causing this sort of zinc usage? I leave the boat under shorepower 24x7...is there a bad ground somewhere? How do I prevent damage to my thru-hulls and metla components under the water line.

I also bought one of those zinc groupers, but I have no idea how/where to install it.
 

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You indicate that shore power is connected 24x7.

What is the shore power powering?

Do you have a battery charger that is connected to shore power and running continuously? If so, I would begin by leaving the charger turned off for a month and then re-check the new zinc.

If the shore power is only connected for the battery charger, you could disconnect it during this time period. But it would be more interesting to leave it connected, to help eliminate possibilities. The process of elimination gets muddied if more than one variable is changed at a time.
 

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Discussion Starter #3
I have the shore power plugged into the battery charge, yes.

Are you suggesting the following:
1) Leave shore power plugged in
2) While shore power cable is plugged in, kill the breaker for the battery charger, but leave the overall breaker open?
 

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Unplug your boat. Because soon the process of elimination is going to be on stuff more expensive than zincs.
 

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I have the shore power plugged into the battery charge, yes.

Are you suggesting the following:
1) Leave shore power plugged in
2) While shore power cable is plugged in, kill the breaker for the battery charger, but leave the overall breaker open?
Yes. But make sure you keep a watch on the zincs (see tager's note above).

My hunch is that you are leaking DC and the battery charger is providing an unlimited supply.

However, you should do some additional searching around here on Sailnet. There have been more than a few threads about similar dockside issues. But the above advice about the process of elimination applies regardless.
 

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It's either your boat, or the boats around you that have a problem. Turn off the shore power and shut down everything, and see what happens next with the zincs. If the problem persists in a month or so, it's not you, but those around you in the marina.

Your diver should be careful if there are electrical currents in the water. Micro-currents can kill a swimmer by interupting muscle functions.

PS -- Just re-read the OP. Living aboard presents a problem. This may be hard to diagnose while dependent on shore power. Perhaps you could request another slip and see if the problem persists there. Talk to the marina manager -- have others had this problem? I agree with the above post that more expensive things are in store if you can't keep putting new zincs in service. You might also try one of those sacrificial "fish" zincs as they don't require a diver to replace them. Also, it may be time to get an electician involved -- he'll probably be cheaper than the alternative.
 

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I'd see if the marina would have an electrician check the docks AC just to make sure it's not leaking. Most of the time it's DC current. One thing you may do to ensure it's not your boat leaking DC current is install a galvanic isolator. I'd also make sure the zincs you are using are for the type of water you are in.

One last tip, move the boat away from the docks and other boats when it's time to dive on it. Better safe than sorry and it sounds like you definately have a problem.

Good luck.
 

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Funny, when I read the OP I got the impression he was not at a marina, but instead was at his own dock. That's why I did not mention some of the other marina-related possibilities.
 

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Discussion Starter #10
Funny, when I read the OP I got the impression he was not at a marina, but instead was at his own dock. That's why I did not mention some of the other marina-related possibilities.
You are correct - this is my own dock behind my personal home in fort lauderdale...no marina.
 

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Discussion Starter #11
Does your shore power come into the boat through an isolation transformer?
I dont believe so. It comes straight out of my house's outside electrical panel. What would an isolation transformer provide? Are those common for homes? How much is the cost?
 

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Discussion Starter #12 (Edited)
PS -- Just re-read the OP. Living aboard presents a problem. This may be hard to diagnose while dependent on shore power. Perhaps you could request another slip and see if the problem persists there. Talk to the marina manager -- have others had this problem? I agree with the above post that more expensive things are in store if you can't keep putting new zincs in service. You might also try one of those sacrificial "fish" zincs as they don't require a diver to replace them. Also, it may be time to get an electician involved -- he'll probably be cheaper than the alternative.
I dont live aboard, the boat lives behind my house. We have one of those canal homes in fort lauderdale. I bought the grouper earlier today and I've already attached it to my port side shroud...according to the B343 newsgroup, this is a bonded/grounded shroud. I attached it to the base where it goes into the hull, but I'm thinking it may be better to attach it to the upper stainless steel parts of the shroud now.

I'm going to be calling an electrician asap...as of this moment, there is no zinc on the prop at all (diver didn't have a spare) - but he is returning next saturday to place a zinc on there asap. I am having severe stomach pains thinking about this...buying this boat was a stretch and having to replace a prop+shaft in a couple years would be a dream-killer

P.S. - my water is "Brackish" - I've heard that in this type of water it may be best to have aluminum anodes...if so, where can one source Beneteau aluminum anodes. Even boatzincs.com only has the normal zinc anodes. And I cant just drop a aluminum guppy/grouper over the size if the prop isn't protected.
 

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I dont believe so. It comes straight out of my house's outside electrical panel. What would an isolation transformer provide? Are those common for homes? How much is the cost?
Without an isolation transformer on your boat, you are very likely taking in stray DC with your shore power, and from the looks of it from your zinc, lots of it. I would immediately disconnect the shore power, then check to see if there is an isolation transformer in the boat. If there isn't, then have one installed before you hook-up your shore power. Also, have an electrician check the quality of your electricity you are sending to the boat.
 

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P.S. - my water is "Brackish" - I've heard that in this type of water it may be best to have aluminum anodes...if so, where can one source Beneteau aluminum anodes. Even boatzincs.com only has the normal zinc anodes. And I cant just drop a aluminum guppy/grouper over the size if the prop isn't protected.
You may be out of luck trying to find aluminum Beneteau anodes. They may actually simply not exist. I know I've never seen one.

You can attach a guppy zinc to your prop shaft and hang the anode over the side. In fact, not knowing the source of the problem and it being a week until your diver can replace the prop zinc, this is probably a good idea.
 

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Discussion Starter #15
Without an isolation transformer on your boat, you are very likely taking in stray DC with your shore power, and from the looks of it from your zinc, lots of it. I would immediately disconnect the shore power, then check to see if there is an isolation transformer in the boat. If there isn't, then have one installed before you hook-up your shore power. Also, have an electrician check the quality of your electricity you are sending to the boat.
Sequitur - I believe the standard battery charger on the boat is a Xantrex TrueCharge 20+...it supposedly has an isolator built in. I'm confused...do I need an isolater in addition to the one built into the battery charger? See description off of Xantrex's website:

Xantrex Technology Inc. - Boats - Truecharge 20+ & 40+ (90-135 VAC) - Product Information

Protection Features

* Over-temperature shutdown and overload protection
* Ignition protected for installation in gas engine compartments (10TB, 20+ and 40+)
* Transformer isolated for safety and to protect against electrolysis
* Reverse polarity protection
* Short-circuit and surge protection
 

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Eats Zincs

Timely post. I was in Rock Hall this weekend (imported labor to help wax and paint OPB).

Our neighbor on the hard....also a 2008 Bene 343...was telling us his prop zinc also has a life well below 6 mos. The way Bene designed the system, there is NO other place to install a secondary zinc.

A short zinc life might be more common on these models??

Jason
 

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If you have a DC leak on your boat, that could be the cause of the zinc erosion. I've previously posted on tracing a DC side leak, and recommend you attempt it, here is my previous post:

If you want to test to see if you have a DC-based ground leak, the test for that is rather simple. The steps for seeing if you have a DC-ground leak are as follows:

First—the preliminary diagnosis test:


1) Turn off all equipment and disconnect any solar panels
2) Disconnect the positive side of the battery banks.
3) Leave the main battery isolation switch turned on for the bank in question
4) Set the meter to VDC mode, range appropriate for your battery bank
5) Connect the meter between the positive terminal and the disconnected cable

The meter should give no reading. If it reads XX volts for your XX VDC system, one of two things is happening.

1) You've left some equipment connected and turned on. This could be a bilge pump, a power feed to a stereo for the radio's memory and clock functions, or a hard-wired fume detector.

2) If you've disconnected all the "hard-wired" equipment and still get a reading, then you've most likely got a ground leak in your boat's DC system.

The Ground Leak Check:

1) Set the meter in Ohm mode and set it to the lowest range (x1).
2) Connect the leads of the Ohm-meter (or multimeter in Ohm mode) to the disconnected positive lead and the negative terminal of the battery.

The meter is now reading the resistance of any circuit to ground that exists in the boat's wiring. The reading on the Ohm meter display can help you identify the cause of the leak.

0-10 Ohms means it is most likely a piece of equipment left on
10-1k Ohms is a low-drain piece of equipment left on, or a serious ground leak
1k-10k Ohms is a minor leak
10k+ Ohms is an insignificant leak

How Big is The Leak?

The ammeter function of the multi-meter can tell you what the current leakage is. If your meter can read up to 10 Amps DC, then you can use it to measure amperage for leaks down to about 1.3 Ohms resistance on a 12 VDC system, or 2.6 Ohms for a 24 VDC system.

To see how big the leak is, put the probes on the positive battery post and the disconnected cable. The meter readings can be interpreted as shown:

<1mA — insignificant leakage
1–10mA — minor leakage
10mA–1A — major leak or some equipment left on
>1A — Usually some equipment left on.
 
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Discussion Starter #18
Timely post. I was in Rock Hall this weekend (imported labor to help wax and paint OPB).

Our neighbor on the hard....also a 2008 Bene 343...was telling us his prop zinc also has a life well below 6 mos. The way Bene designed the system, there is NO other place to install a secondary zinc.

A short zinc life might be more common on these models??

Jason
Jason - you are correct. Beneteau 343 are (poorly) designed to use up zincs...but even on the 343 yahoo group message board, people get 2-3 months out of an anode. I barely got 1 month....even less if you "follow the book" and replace the zinc when it gets to 50%...hence the sense of panic/dread that I'm doing long term damage to my metal bits.
 

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I, too, use a bit of zinc and have SD's test on my agenda, but have a follow-up question. If the test indicates that I do indeed have a ground leak, how does one go about finding and rectifying it? What exactly is a ground leak?
 

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Discussion Starter #20 (Edited)
I am thinking of buying one of these:

Corrosion Reference Electrode




It plugs into your multimeter to track in water electric. Anyone use this to diagnose their anode issues? Could be useful when pulling into a new marina as well to see if they have issues.
 
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