Do I have a grounding issue?

[dollar7499]

I have a 2002 Crownline 262CR 5.7l with B3 drive and all my daisy chain cables appear to be connected, but I kept my boat in a marina in Hilton Head SC for 2 nights and my magnesium (I normally boat in freshwater) anodes were EATEN! Probably 10% gone in 2 DAYS. Is this normal for magnesium in saltwater? My mercathode is also not connected because I broke the head and wasn't sure if I needed it because I trailer the boat. Thoughts?

 

[GA_Boater]

You don't have a grounding issue, you have a busted Mercathode system. Fix it.

 

[Scott Danforth]

in addition to GA's comment, most boats that park in a marina have a giant zinc with an alligator clip they toss over-board. Marinas are notorious for stray voltages.

here is what I am talking about. Martyr makes them.

 

[alldodge]

While your Mercathode might need to be fixed, you need to get the Magnesium anodes off and put aluminum or zinc on fast. The Mag anodes only provide 1/5 the protection salt water over Aluminum, and why they are great for fresh water

https://www.boatingmag.com/how-to/choosing-right-sacrificial-anode

Other issues which can cause them to be depleted faster is if your boat is grounded very well and the boat nearby has a bad grounding system, or even the dock your using.

 

[dollar7499]

I will definitely be investing in AL anodes for the rare ocean trip!!

Thanks for the replies, the boat is back on the trailer far from the ocean, that was just a quick trip to the coast, the rest of my boating will be in fresh water. I am repairing my mercathode, but want to research how much it drains the battery when we spend the night in a cove.

Is there a testing regimen that can be done to make sure everything is grounded properly and there is no stray voltage? I am new to this boat and just want to be thorough

 

[alldodge]

There is a way to test how well its doing. The instructions also lest the probe which is used. It works pretty well, bought one some years back. If your not plugged into shore power the issues are less

http://www.boatfix.com/merc/servmanl/14/14a7.pdf

 

[Outobie]

quick question on those grouper zinks...I just looked them up and it says to attach the alligator clip to a bolt on the transom mount for the outdrive.

my question is since I twin outdrives do I need two of them? should I connect an extra alligator clip connecting the two transom plates together?
thanks

 

[Bt Doctur]

I would add a bonding strap between the transom housings and another across both engine blocks,and make sure the neg battery posts are tied together too

 

[Grub54891]

all my daisy chain cables appear to be connected

In reality, the bonding wires should not be daisy chained. They should run separately to a bonding buss. Any bad connection in the chain= no more bonding. Mfg build them cheaply as possible, daisey chain is cheaper. ​

 

[QBhoy]

There is a well known marina near me that is famous for eating bravo drives. In fresh water. It’s the shore power system on the jetties that isn’t earthed properly.

 

[Grub54891]

There is a well known marina near me that is famous for eating bravo drives. In fresh water. It’s the shore power system on the jetties that isn’t earthed properly.

I agree that improper marina setups can be a huge issue, but it should be eating more than just Bravos. Everything else would be affected also.

 

[QBhoy]

Yeah...just that the bravo seems to get it worse. The alpha there get it at the trim pipe fittings.