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Discussion Starter #1
I know there is a wealth of information about electrolysis and zincs and bonding and I have been trying to read some of it but I am sort of pressed for time....

My 84' Morgan 323 is new to me and as I bought it last Spring. I am storing it in the water at my local dock. Today when I went to check on it I took a close look at the shaft and stuffing box. I can't remember exactly what they looked like during the summer as the boat is still so new to me but today it looked very green and pretty corroded and I am almost positive it didn't look that way when I kept it on my mooring during the spring summer and fall. I changed the shaft zinc in the end of August so it has been about 6 months.

One major difference of how I keep the boat is that in the offseason it is in a slip, connected to shore power with a temp regulated heater in the cabin connected to the boats electrical system. Anyway I am going down to the boat again tomorrow with someone who knows a lot about boats and maintenance and I think I will also be able to see the condition of the shaft zinc since it will be calm winds tomorrow. (today was pretty windy and the water was turbulent so I could not see the condition of the zinc as it was very blurry)

So my question is lets say the water is clear and I can see the shaft zinc tomorrow and if it is very eaten away what are my options? The marina it is at now has no lift, the boat is shrink wrapped and there is no way I am de-winterizing it and sailing it somewhere else anytime before mid April. Short of paying a fiver with a dry suit, is there anyway I could hang a zinc around the shaft with metal wire? Place a zinc somewhere else inside the boat that is accessible? I honestly think the issue is related to the Shore Power since I never saw this the season out on my mooring and I don't want it to ruin my boat because of stray current. Any suggestions or help would appreciated.
Thanks in advance.
 

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Lynger1
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One major difference of how I keep the boat is that in the off season it is in a slip, connected to shore power with a temp regulated heater in the cabin connected to the boats electrical system.

I have that problem long time ago
If you use shore power in winter on blocks with no earth
You need to earth boat with 60cm brass bar hit it in the ground below boat and earth shore power from boat to this

Other thing you can do is put clamp on prop-shaft with earth during storage
Hope this Will solve you're problem
 

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Discussion Starter #3
One major difference of how I keep the boat is that in the off season it is in a slip, connected to shore power with a temp regulated heater in the cabin connected to the boats electrical system.

I have that problem long time ago
If you use shore power in winter on blocks with no earth
You need to earth boat with 60cm brass bar hit it in the ground below boat and earth shore power from boat to this

Other thing you can do is put clamp on prop-shaft with earth during storage
Hope this Will solve you're problem
Thanks for the suggestion but the boat is actually in the water in a slip - not on land on blocks.
 

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moderate?
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Green is not a big problem...but get some good light on the area and inspect closely for any sign of pink which is a big problem.
If the zinc has not been changed since last spring...you are overdue for an inspection but with cold water and NO pink...you can probably hold off a bit. If there IS electrolysis going on, you can hang a zinc fish on a wire from a grounded part of the boat to overboard to try minimize damage but that is no guarantee.
The only way to truly protect the shaft is with a shaft zinc...which means a diver if you are still concerned after a close inspection.
 

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Discussion Starter #6
Cam,
Thanks for the suggestion. I will try and take some pictures tomorrow morning and will post them so if you happen to check back maybe you can let me know what you think. Also the zinc has been changed at the end of the summer, late August 08' - not the spring but either way I should be able to se the status of it tomorrow assuming the water in the slip is nice a calm.
Thanks again
 

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It would have to be a fairly extreme situation for your zinc to have depleted and serious damage to your running gear occur within 5 months. Not that it couldn't happen, but it would be unusual. You are probably fine. I don't know what diver rates are like in your area, but here it would cost you in the vicinity of $50.00 for an inspection. If your diver is reasonable (like me :D ) that price would include the installation of a zinc or two (zincs would likely be extra). Couldn't hurt to carry two on your shaft instead of one, BTW.
 

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Discussion Starter #8
Fstbottoms - if you lived here I would take you up on that offer in a heartbeat. It is also 17 degrees F here today though so I would need to find a diver with a dry suit.

Ok so here is the update. I uploaded a picture of what the shaft looks so now that you can all see it firsthand, what do you think? Also I coudl see that the zinc on the shaft is very deteriorated and half missing so I know there is a problem some where.

I also found out that the through holes on the boat are not bonded, but they look to be in good shape. Just the shaft is what scares me. What I am doing for the time being is I turned off the shore power and disconnected the cord. I am going to polish the inside portion of the shaft with a stainless steel brush and bronze polish. I am then going to get one of those fish zinc things with a 15' long wire. I am going to wrap the end of the wire around the inside portion of the shaft which is shown in the picture and then run the wire out into the cockpit and over the side where the fish zinc will sit in the water. Do you think this will help?

Thanks again for everyones responses:)

 

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Telstar 28
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NK235—

That kind of surface corrosion is pretty normal for a bronze shaft, especially inside the boat. Exactly where are you seeing a zinc in this photo. Zincs are normally on the exterior portion of the shaft, as the need to be immersed in water to function properly. Occasionally, you'll see one on a shaft inside the boat, but that is generally as a safety measure, so the prop shaft can't fall out....but not to prevent corrosion.
 

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Discussion Starter #11
Cam, and SD - Thanks for the comments...I think I will be able to sleep at night now knowing this isn't something bad:) I was pretty worried for a while there.

SD - The zinc I was referring to IS on the outside in the water. I can see it from the dock if I bend down and look under the stern as the prop, shaft and zinc is visible. I am on my way down there again now. I bought one of those $50 grouper fish zincs and I am going to attach the wire to the shaft inside the boat and lead the fish zinc into the water for protection because I know the external zinc is shot.

Thanks again though
 

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Ok so here is the update. I uploaded a picture of what the shaft looks so now that you can all see it firsthand, what do you think? Also I coudl see that the zinc on the shaft is very deteriorated and half missing so I know there is a problem some where.



My main concern is with the hose clamps on the stuffing box hose. Replace those before you do anything! Also use AWAB non-perforated hose clamps when you do so..

Beyond that clean up the stuffing box & shaft with a brass brush and some Scotch-Brite. The box and shaft should be a uniform color with no splotches of a pinkish tinge.

Contrary to popular belief many marine bronzes do contain small amounts of zinc and can show signs of dezincification.

Tobin Bronze, what most marine shafting was made from, is generally 60% copper (Cu), 39% zinc (Zn) and 1% Tin (Sn). Tobin Bronze contains rather large amounts of zinc. If you are going to see dezincification it would more than likely be on the shaft rather than the stuffing box which is most likely a real bronze with a very low zinc content..

The difference between brass and bronze is essentially Zinc content. Brass is loaded with it and Bronze, real bronze, not Manganese or Tobin, do not, in content above 15%.

The main alloys of brass are, copper and zinc. The main alloys of bronze are copper and tin. The names of said alloys can cause lots of confusion as “Manganese Bronze”, what lots of props are made from, and “Tobin Bronze”, sometimes called naval brass, are actually alloys of 60/40 brass with about 1% manganese or 1% tin added. Even this little bit if Sn puts them in the bronze category instead of brass.??

These spots are dezincification of brass. It will look similar on a Tobin Bronze prop shaft..
 

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Exactly where are you seeing a zinc in this photo.
I don't think he was indicating that he was seeing a zinc in the interior end of the shaft. I think he was saying he noticed some corrosion on the inside (pictured above) and was hoping to be able to see the zinc on the shaft underwater (visibility permitting) and determine if it had been badly depleted or or not.

nk235, here are the web sites for a couple New York dive companies. One is based on Long Island, not sure about the other. Looks like you get a zinc installed for less than $100:

Boat bottom cleaning hull cleaning

BottomDwellers.net - In water cleaning,salvage and repairs
 

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Discussion Starter #14
I cleaned up the shaft and stuffing box a bit and a lot of what I thought was corrosion just came off. Also when I was cleaning the shaft, I rotated it a little bit and then when I looked at the prop again from outside, low and behold I actually still hade my Zinc:eek: oops. I guess I couldn't see it for whatever reason yesterday and this morning so all and all I guess this post was really for nothing so I apologize. I am 24 so I know I have a lot to learn but I take great pride in careing for my boat and when I noticed this I freaked out. I did attach the fish grouper zinc with copper wire around the shaft just for peace of mind added protection. Again thanks to everyone who replied to help me out. Also those 4 rusted house clamps are being switched out this week.

Here is what it now looks like:

 

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I'd hose clamp that wire to the shaft if I were you. Won't take much to make it lose whatever tenuous connection it has otherwise.
 

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Discussion Starter #16
I'd hose clamp that wire to the shaft if I were you. Won't take much to make it lose whatever tenuous connection it has otherwise.
It actually is. You just can't tell from the picture but thanks anyway.
 

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The green corrosion is common on bronze, brass, and copper, and other such or smiler metals when in contact with air and water, The fact that your zink is gone in about five months is likely a result of being in the marina and your shore power connection. If you have or know someone that has a Amp clamp that will go around you shore cord you can check for AC current leeks on your vessel. You should see less then .03 or three one hundredths of an amp. It may be the near buy boats to, AC or DC.

The hose clamps need immediate attention :hammer
 
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