Zinc's gone in 3 months!

[b12ptr]

newbie here, have a 2001 proline 29 walk, keep it water year around in upper Chesapeake bay.

Did my yearly maintenance in mid Aug, replaces all Zincs etc… now in end of Nov, my Zinc’s are almost gone. I would say about 25-30% left  in ~3months. I just pulled the boat out last Monday, freshened up the outdrives and replaced the Zinc’s.

But before i put the boat back in the water, I am trying to figure out what could be causing the issue. I have never seen them like this time.

I have Galvanic Isolator in the boat and Mercathods on both the engines.

Can someone give me simple test I can do with a voltmeter to check each system. Also, any other ideas.

Much appreciate you help.

[231CALIFORNIA]

are they B3 drives? I hear they eat zincs faster
also are you using fw anodes "zincs" =magnesium i think, or saltwater anodes
Either Zinc or aluminum alloy.
merc has recently changed the saltwater anode to aluminum form zinc i heard.
also if your props are stainless, your boat is in a marina or it is hooked to shore power or battery charger other factors come into play.
otherwise get the big zinc guppy or grouper on a cable with an aligator clip and hang it over the side, clip connected to bonding system or neg side of battery for supplemental protection.
zincs/anodes  are supposed to sacrifice themselves mercathode is supposed to help control things a bit.This may not be the exact procedure but
you can also test your boat by  touching one end of a sensitive voltmeter to your negative bat terminal and the other end to the water or a zinc hun over the side on a wire to see if there is voltage, then you can disconect things to see what influences that voltage.
in the mean time, paint all exposed metal that isnt stainless  or  an anode like outdrive skeg, aluminum prop,  etc if any.

[b12ptr]

Thanks 231california for getting back to quick.

I do have B3’s with stainless steel props.

Interesting point about different types of anodes. I did not realize until today there were indeed three types of metals. I am not sure what type I put on it.. I have a feeling since they were $50/ea, these were Zinc. Considering brakish water, which ones would you recommend, i will keep that in mind next time.

Boat stays in the water at the marina and is plugged into shore power year around. Luckily I checked and pulled it out.. so there was no damage to the drives and the paint was pretty good.

Thanks for the tip on testing.. I was wondering if there is a test I can do while the boat is out of the water.

Also, I looked into Zinc Guppy.. most likely will install one if I am not able to find out. Also will test while boat is in the water.

-basit.

[231CALIFORNIA]

I dont know any good out of water test other than to inspect everything aboard for sealed wiring, tight connections, corrosion and new anodes.
talk to other bravo 3owners in your area and see what they are doing , someone must have it right.?

[b12ptr]

putting it back in the water tomorrow... will do the test in water.. along w/Zinc Guppy's. thanks again!

[GasCanII]

b12ptr;
I have a 1997 Murcruiser Bravo II with a S/S prop. I also keep my boat in the  salt water, and had a problem with my sinks not lasting.
I called Mercury Tech. line and they said to use alum. in salt or brakish water. Hope this helps.

[b12ptr]

GasCanII:

thanks, i picked them up before putting the boat back.. also, got 2 guppy's... will see how they turn up in a month.

[seabob4]

Do a google search on B3 zincs, there is a lot out there on the poor design by Merc...and how they won't admit it.  They didn't allow enough room on the propshaft for the proper zinc...

[Hugh]

I wouldn't know a B3 from a B52, but if your galv isolator is working, the zincs are sacrificing themselves and your prop shaft is looking dapper...it's all good except the maintenance effort. 

If the B3s are too small, get a big fat anode and plop it over the side, and let it rot away instead of the bitty zincs.  It may be inconvenient to clip it on and unclip it from the prop shaft or from the B3, but probably less hassle than replacing the zincs every 3 months.

Check this thread for more info:  http://www.theprolineguy.com/post2624.html#p2624

[b12ptr]

update, its now been over 7 months and the new Zinc's still look good about 70-80% left. So i think better quality ZInc's and Guppy may have done the trick.. however, will know better when i pull the boat out for maintenance . will update then.

thanks to all who pitched in and helped. greatly appreciate it.

• apenny
• Intrepid