Salt Water or Fresh Water Zincs?

[Condor1970]

Ok, I have a 1989 Regal Medallion with a Merc 3.0L and an Alpha One - Gen I outdrive. Currently it has a set of "Freshwater Only" zincs on the outdrive.

I know they make salt water zincs actually made of zinc, instead of magnesium and aluminum which I think fresh water zincs are mainly made of.

So, here's my dilemma. The boat is a basically a trailer queen I use for tubing with the kids at the local lakes. However, if I want to start using it for running around the Puget Sound, and do a little fishing, do I really need to get a set of salt water zincs? If I switch to salt water zincs, can I use it in the lakes with no issues, since the fresh water zincs are made of magnesium?

Without changing zincs back and forth, how should I go about this, if I want to use the boat for both environments?

 

[smokeonthewater]

If you are trailering you don't need to worry about anodes.

 

[Scott Danforth]

you are over thinkin this. prior to people complaining about zincs having a 6 month life span in salt water, there were only zinc annodes. so to come up with a zinc that lasts longer in fresh water, they developed different annodes

leave the "fresh water" zincs. they are actual zinc and just simply disolve faster in salt vs fresh water (because they are working). they will not last as long, however will protect your drive.

 

[reelfishin]

Freshwater anodes are generally magnesium alloys, these will deteriorate rapidly in salt or even brackish water. For salt water most used zinc anodes or aluminum anodes. Aluminum anodes last a bit longer and don't have the issue of becoming coated with calcium deposits over time. Most glass boats use zinc anodes in saltwater.
The rule of thumb is zinc for saltwater, aluminum for salt or brackish water, and magnesium alloys for freshwater only.

I agree with the post above, in most cases you won't need an anode if your trailering your boat but it doesn't hurt and if you do on occasion decide to leave it in a slip for a while, its protected.

I boat in both salt and freshwater, I run zinc anodes with the thought that anodes are a bit less important in freshwater, especially since I trailer my boats.
I spend most of my time in brackish or saltwater so it only makes sense to stay with the zinc anodes. You'll know if you have magnesium anodes in saltwater, they will deteriorate FAST. They'll start showing major pitting after only a day or two out on the water, if not faster. My one outboard had a single magnesium anode on the av plate from its days in freshwater, it was down to nothing but the mounting bolt after four outings in the salt.