How important are the "zincs?"

[bronxlatetour]

I have a 1990 Sea Ray 250 DA with the 7.4 Bravo. While reinstalling my prop I noticed that the zinc that fits flush onto the bottom of the out drive above the prop is gone. I still have the two that fit around the hydrolic cylinders and the two on the trim tabs. I trailer my boat and it is only in the water for the day. Do I need to replace it and if I do where would I find one. Thanks in advance.

 

[stevieray]

Re: How important are the

Re: How important are the

the zinc that fits flush onto the bottom of the out drive above the prop is gone

When you say gone - do you mean missing completely or corroded away to almost nothing (can you see the attaching bolt sticking down)?

 

[bronxlatetour]

Re: How important are the

Re: How important are the

Yes, it must have loosened up and fallen off. I see the bolt hanging.

 

[stevieray]

Re: How important are the

Re: How important are the

Do you usually buy your parts locally or on line? Any marine parts store will have these individually or in kits with all the other anodes (proper term for "zincs") that are on your drive. I would suggest aluminum anodes since it is out of the water a lot. Zinc will develop a coating that renders them nearly useless as corrosion protection after they sit out in air for a while.

 

[bjcsc]

Re: How important are the

Re: How important are the

I agree with most of what has been said, except I would never use an aluminum anode. Most aluminum does not protect iron or low alloy steel or cast aluminum alloys - many of which are present in your driveline. If you are in saltwater, zinc is recommended. If you are in freshwater, magnesium. The surface of the zinc has no relevance to its electrical properties. All that is important is that the anode's attaching surface is clean and securely attached to a clean surface on your driveline - you maintain that as you would any other electrical connection. To answer your question directly, yes they are very important and you should replace it as soon as you can.

 

[stevieray]

Re: How important are the

Re: How important are the

If you are in saltwater, zinc is recommended. If you are in freshwater, magnesium.

If you keep it in the water, I agree. If it spends more time on the trailer, I stick by the aluminum.

The surface of the zinc has no relevance to its electrical properties.

If that is true, why do fouled electrical connectors inside the boat create so many problems? The issue is the same - transfer of electrons (or ions, as it were). I've seen the coating problem firsthand on mine - I'm speaking from direct experience, not only theory.

 

[Scaaty]

Re: How important are the

Re: How important are the

Post getting way out of hand. Simply go get another Anode...there cheap, and besides, they are there for a reason.

 

[Scaaty]

Re: How important are the

Re: How important are the


Zinc will develop a coating that renders them nearly useless as corrosion protection after they sit out in air for a while.

Can you expand on this a touch? Never heard of it..

 

[stevieray]

Re: How important are the

Re: How important are the

Scaaty - there was this crusty white stuff on some of the outer surfaces of the anodes after it sat on a trailer for a little over 7 months a couple of winters ago. Didn't think anything of it since the anodes were in otherwise great shape. Put it in the drink that whole summer & when I pulled it in the fall, the aluminum on the drive was corroded real bad, and the anodes had lost no metal - at all. Put an ohmmeter on them & resistance was real high. Scratched away some of the coating & resistance went to zero. Found out zinc will oxidize in air & form a resistive coating over time, but not in water (since it is actively ionizing constantly). Put aluminum ones on & the problem did not appear over last winter storage & drive looks great in the water this season. That's the whole story.

Post getting way out of hand

I don't think it is - a forum by definition is a medium of open discussion. As long as there is intelligent discussion, it's not out of hand.

 

[Dunaruna]

Re: How important are the

Re: How important are the

[colour=blue]stevieray is correct, that 'crusty white stuff' coats the anode and reduces the electrical potential which will greatly reduce the affectiveness of the anode.

A regular wire brushing fixes the problem.

bronxlatetour, is your boat pened or trailered?

 

[bruceb58]

Re: How important are the

Re: How important are the

That is why aluminum alloy anodes are often used...they are self cleaning in salt water.

 

[Don S]

Re: How important are the

Re: How important are the

You guys need to get your facts straight. Aluminum alloy anodes were used for one reason and one reason only, They protect the drive better. They are a maintenance item. If they are corroded, replace them. A lot depends on the alloy of the drive and the alloy of the anode. It's not the same alloy of aluminum as the drive is, think about it.
Merc says use their aluminum anodes (in salt water) because they protect better than zinc. They used to use zinc, but stopped years ago. Here is the link to the bulletin WHEN the anodes were changed to aluminum.

http://www.boatfix.com/merc/Bullet/91/91_19.pdf

Here is an excerpt from a 2003 service bulletin regarding the quality of the alloy now used:

Several years ago Mercury Marine began using aluminum anodes in most of our
applications. We moved away from zinc anodes because the more galvanically active
aluminum anodes provide better protection for our drive components. It is extremely
important that aluminum anodes be produced from the correct alloy or they will fail to
protect the drive system as intended. Aluminum anodes should be manufactured to meet
or exceed the United States military specification MIL-A-24779(SH). All anodes sold by
Mercury Marine exceed this specification.

 

[Scaaty]

Re: How important are the

Re: How important are the

Post getting way out of hand

I don't think it is - a forum by definition is a medium of open discussion. As long as there is intelligent discussion, it's not out of hand.[/quote]


I disagree. It turned into a anode material difference of opinion, but did ZIP to answer the ORIGINAL question. Start another thread for a discussion of anode material difference. Just my opinion......did you happen to notice bronxlatetour never came back after the third post?

 

[bronxlatetour]

Re: How important are the

Re: How important are the

So, I boat in saltwater and trailer it. I have a Bravo 1. Would I be correct in saying I should replace them all with aluminum?

 

[Don S]

Re: How important are the

Re: How important are the

So, I boat in saltwater and trailer it. I have a Bravo 1. Would I be correct in saying I should replace them all with aluminum?

Yes, did you read my previous threads and the link?

 

[stevieray]

Re: How important are the

Re: How important are the

I disagree. It turned into a anode material difference of opinion, but did ZIP to answer the ORIGINAL question. Start another thread for a discussion of anode material difference. Just my opinion......did you happen to notice bronxlatetour never came back after the third post?

I gave my advice to bronx (which ended up being correct) on what & where to buy as soon as I had a clear picture of his problem. The next post contradicted my advice & gave some questionable information as well, so some further discussion was in order. I think we all learned at least a bit more than we knew before, right? (Except maybe for Don S)

 

[HT32BSX115]

Aluminum VS Zinc

Aluminum VS Zinc

It's pretty clear to me (Mercruisers position on zinc vs Al).

Aluminum will protect better than zinc in salt or fresh water.(period)

The service bulletin states this pretty clearly.

It also implies (to me) that if you have a warranty and you do not comply with the service bulletin, you won't have a warranty!


Cheers,

Rick

 

[Scaaty]

Re: How important are the

Re: How important are the

I disagree. It turned into a anode material difference of opinion, but did ZIP to answer the ORIGINAL question. Start another thread for a discussion of anode material difference. Just my opinion......did you happen to notice bronxlatetour never came back after the third post?

I gave my advice to bronx (which ended up being correct) on what & where to buy as soon as I had a clear picture of his problem. The next post contradicted my advice & gave some questionable information as well, so some further discussion was in order. I think we all learned at least a bit more than we knew before, right? (Except maybe for Don S)

This WHOLE thread should be in BOAT TOPICS. I give up