2006 340 SDA zinc questions w/v-drives

[boatrboy]

I am in salt water in New England and launched the boat May 1 when I bought it.

The boat was just hauled and I saw the transom zinc looks like it disintegrated.

What material should I use? Zinc or aluminum? The trim tab zincs looked ok compared to the transom one. My last boat had a bravo 3 so I used aluminum but with v-drives I’m not sure what to use. I also read that Sea Ray doesn’t recommend shaft zincs and I verified I did not have them.

Also the mounting looks weird. Any thoughts on if it’s correct. I did not check the inside of the hull yet to make sure the ground wire is correct but I will assume it’s connected properly and verify that this weekend.

Thanks

 

[KevinC]

I am in salt water in New England and launched the boat May 1 when I bought it.

The boat was just hauled and I saw the transom zinc looks like it disintegrated.

What material should I use? Zinc or aluminum? The trim tab zincs looked ok compared to the transom one. My last boat had a bravo 3 so I used aluminum but with v-drives I’m not sure what to use. I also read that Sea Ray doesn’t recommend shaft zincs and I verified I did not have them.

Also the mounting looks weird. Any thoughts on if it’s correct. I did not check the inside of the hull yet to make sure the ground wire is correct but I will assume it’s connected properly and verify that this weekend.

Thanks
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If the anodes are corroding you know they are working otherwise it would be something more important. I have been using Aluminum in salt water which seem to work well. You also need to make sure all your anodes are of the same type. So don't mix aluminum, magnesium and zinc.

The main hull anode looks correct and obviously needs to go. Depending on your environment you may get 2-3 years out of one. It's not a time thing - it's all about percentage remaining.

As you mentioned Sea Ray does not recommend shaft anodes. I had them and removed them without issue. I also paint my shafts, props, struts, rudder and exhausts with the cold galvanizing zinc spray. Its worked for me so far with no hard buildup.

The trim tabs are pretty straight forward - usually wind up replacing annually or if not too bad every other year.

I also have south bay strainers that have anodes and a bow thruster that has an anode - do not forget to check them.

The other main concern is ensuring that all you green bonding wire are connected.

-Kevin

 

[The Bill Collector]

https://www.defender.com/html/zincs_info.html

I use zinc in salt water. I usually do not see as much disintegration in 6 months as in your picture. Your rudders and trim tabs both need zincs (or whatever you decide).

 

[Lazy Daze]

Zinc is not better than aluminum and Al is not better than Zn. There are so many factors at play (running gear setup, electrical items onboard, other boats and systems, marina shore power setup, even the particular body of water you're in... to name a few) that it's near impossible to compare (fully, anyways) to others in different areas. The best thing you can do is to compare, and check with, other boats in your area and see what they've been using. Check with people that have been there for at least a few years.

In the end, though, as mentioned, you WANT to see those anodes getting eaten up.

 

[boatrboy]

Thanks for the quick reply.

TBC - I do not have have holes for rudder anodes that I can see, so I will assume they (zincs) are not meant to be there on my boat.

LD - I have been in this slip for 19 years but with my 270 and I always used aluminum with the b3. They were eaten up every year. I just don't have any experience with this new boat there other than what I saw when I pulled the boat out this year. I am basically the biggest boat in my dock so almost everyone around me is a smaller fishing boat. Unfortunatly they are of no help. I will reach out to my friends on the other dock where the larger cruisers are and see what they are using.

Kevin - No bow thruster so no need to worry about that. I change mine every year so I will look into Aluminum for the tabs and transom. On my last boat I used the cold galvanizing paint on the trim tabs too - did you use this as well on yours or only the rudders and shafts?

I was purchasing the home depot version rather than the Pettit prop coat.....

 

[The Bill Collector]

On my last boat I used the cold galvanizing paint on the trim tabs

I use bottom paint except for the circle of the anode... Props & shafts I leave bare.

 

[wayne0]

If you have some one next to you with an electrical leak, it will eat your anodes. Zinc or aluminum both work. Both are sacrificial. I have mixed both with no issues. AL for hull, ZN on trim tabs and shafts.
BTW, my 2000 340DA (bought used) had shaft zincs and has for the 10 years I've owned it. They get eaten up too. I don't know what SeaRay is selling.

 

[boatrboy]

Last weekend I was able to remove them and found them to be zinc (based on their weight). I did not realize how thick the hull one was and that it had steel inserts for the bolts.
In my slip the boat next to me has not shore power connection. There is only one boat close by with a shore power connection. From the distance in my photos is that close enough to cause stray current?

 

[brewster16]

I have always used zinc sacrificial anodes on my boats (which included a 340). Large transom zinc is good for a year but I replace trim tab and rudder zincs every 6 months which in my marina is about right based on the noted degradation of those anodes at 6 months. Sea Ray does not recommend shaft zincs. I believe it is based on fact that when degraded they can snap loose under way and do damage to props/shafts. I also have bow thruster and pencil zincs on my Diesel engines.

 

[ttmott]

If you are in salt water use zinc based anodes for a Fiberglass boat. The only aluminum one should be in the water heater (which is fresh water).
If that transom zinc is completely gone in six months, actually it looks like there were two zincs mounted, then there is a problem electrically. The good news is the zincs are going away rather some other piece of the boat. It can be current leakage from the dock, another boat, or your boat. I suspect as your trim tab zincs are in such good shape that there is a problem with your boat's electrical. Quite likely the galvanic isolators are kaput. You won't know until the water around the boat is tested. I bought a Silver Silver Chloride test cell which has been invaluable for me to get my boat wrung out and the garbage scow next to me out of the marina. This is the one I purchased -
https://www.boatzincs.com/corrosion-reference-electrode.html

 

[boatrboy]

Thanks Tt.

I’ll have to check it in the spring. I have that same electrode. I checked the ground wire to the bolt on the inside of the hull and it appears to be clean and in tact. I did not notice where the galvanic isolators are on my boat so I will research that. I will be ordering zinc anodes over the winter for next season.

 

[mrsrobinson]

Boatzincs.com taught me what I know when I called them to order zincs my boats application. I switched the type based on their inputs.

 

[cleanman222]

I have been at a marina in Mystic CT for 21 years and used zinc on all three of my boats. I have not seen much degradation of the zincs over the last few years on my 2004 340 Sundancer, except for the shaft zincs. My trim tabs and main zinc look like new (I didn't replace them this year.) I did, however, replace the shaft zincs. It certainly makes sense not to have a shaft zinc break apart and hit the prop, so maybe I will not add them next year. I was unaware that Sea Ray does not recommend shaft zincs. This boat came with them in 2015, so I just put them on each year since.

 

[ttmott]

I have been at a marina in Mystic CT for 21 years and used zinc on all three of my boats. I have not seen much degradation of the zincs over the last few years on my 2004 340 Sundancer, except for the shaft zincs. My trim tabs and main zinc look like new (I didn't replace them this year.) I did, however, replace the shaft zincs. It certainly makes sense not to have a shaft zinc break apart and hit the prop, so maybe I will not add them next year. I was unaware that Sea Ray does not recommend shaft zincs. This boat came with them in 2015, so I just put them on each year since.

It would bother me if my zinc's were not eroding at all; especially if zincs on the propeller shafts were eroding and no others were. Trim tabs - eh, not so concerned; just keep a sharp eye on the edges of the tabs. But if the hull zinc isn't getting consumed I would suspect an issue with the bonding system.

 

[cleanman222]

I would estimate my hull zinc was about 90% of the new one I put on last season. Thanks Tim. Is it possible I was exposed to much less electricity the last couple years?

 

[ttmott]

I would estimate my hull zinc was about 90% of the new one I put on last season. Thanks Tim. Is it possible I was exposed to much less electricity the last couple years?

Possible but many things can be the cause. What bothers me is the zinc's on your propeller shafts are going away but the hull is not. This tells me that the least resistance for galvanic electrical current is through the shafts. Remember that your battery grounds, AC electrical grounds, AC neutral (when generator is operating), and the boat's bonding system are all connected to that large main grounding plate. Then large wires go to the engines from that main grounding plate. Very low resistance through the drive train.
Between that main grounding plate and the hull zinc there should be a resistance of less than 1 ohm. If greater then the galvanic current will find a lower resistance path and if that path isn't protested it will take any metals with it. In your case the shaft zincs which for SR shouldn't have any. This is why I suspect you may have a bonding system issue.

You should get a Silver Silver Chloride test cell and go through the entire test process to determine the health of your bonding and AC power isolation systems. The testing will also determine if a source external to your boat is leaking current into the water. the test cell boatzincs.com sells comes with very good instructions.

Oh, one thing of note is the lack of zinc erosion on your trim tabs indicates that either there is no galvanic current in the water (rare) or the zincs are not bonded to the trim tab metal - someone attached the zinc to the paint on the trim tab rather than removing the paint ensuring a metal to metal contact. Trim tabs are not connected to the boat's bonding system so unique zincs on them is essential.

 

[cleanman222]

Possible but many things can be the cause. What bothers me is the zinc's on your propeller shafts are going away but the hull is not. This tells me that the least resistance for galvanic electrical current is through the shafts. Remember that your battery grounds, AC electrical grounds, AC neutral (when generator is operating), and the boat's bonding system are all connected to that large main grounding plate. Then large wires go to the engines from that main grounding plate. Very low resistance through the drive train.
Between that main grounding plate and the hull zinc there should be a resistance of less than 1 ohm. If greater then the galvanic current will find a lower resistance path and if that path isn't protested it will take any metals with it. In your case the shaft zincs which for SR shouldn't have any. This is why I suspect you may have a bonding system issue.

You should get a Silver Silver Chloride test cell and go through the entire test process to determine the health of your bonding and AC power isolation systems. The testing will also determine if a source external to your boat is leaking current into the water. the test cell boatzincs.com sells comes with very good instructions.

Oh, one thing of note is the lack of zinc erosion on your trim tabs indicates that either there is no galvanic current in the water (rare) or the zincs are not bonded to the trim tab metal - someone attached the zinc to the paint on the trim tab rather than removing the paint ensuring a metal to metal contact. Trim tabs are not connected to the boat's bonding system so unique zincs on them is essential.

Tim
Thank you for taking all this time to analyze my electrical system. You bring up interesting points that I will have to investigate. Yesterday, I observed the green wires attached to the transom in the engine compartment were tight and clean (no corrosion). I will be back on the boat this weekend and inspect all the green wire connections.
FYI, I normally tape over my old trim tab zincs before I bottom paint and then usually replace them. However, next year I will clean the area under and around the zinc to ensure there is no paint between the tab and the zinc.
As for the shaft zincs, do you recommend I remove them and not use them in the future?

 

[ttmott]

Tim
Thank you for taking all this time to analyze my electrical system. You bring up interesting points that I will have to investigate. Yesterday, I observed the green wires attached to the transom in the engine compartment were tight and clean (no corrosion). I will be back on the boat this weekend and inspect all the green wire connections.
FYI, I normally tape over my old trim tab zincs before I bottom paint and then usually replace them. However, next year I will clean the area under and around the zinc to ensure there is no paint between the tab and the zinc.
As for the shaft zincs, do you recommend I remove them and not use them in the future?

A few of the owners here in this forum put anodes on the shafts but most don't. I don't. There is significant engineering that goes into designing the galvanic bonding system on our boats; I tend to align with that. But with that said I would rather have shaft anodes be sacrificed rather than the tips of propellers if the OEM system isn't working.
BTW - the idea of a shaft zinc flying off and damaging the hull is pretty much a wive's tail. The energy just isn't there....

 

[mrsrobinson]

Agreed, no corrosion is not a good thing IMO. I am in fresh water, after 7 months the news ones had a lot of corrosion on them, which I liked. Lots of aluminum left but corrosion. I do not put them on my shafts nor do I think SR did from the factory.