Concrete dock in PGI (Sarasota: store, underwater, counties)

[wpc691]

Originally Posted by Macgregorsailor51

Sorry Marty: I was, am still , working on the pool and reading here on my "Breaks" : ) Ya I meant to say Thats Not a Half Bad Idea.. could there be better solutions , like repair the fault? Yea : ) But that is a quick easy cheap , sort of solution.. : )

Fixing the fault is the best idea, but we're all surrounded by dozens of docks, lifts and shore power installations. The chances that they're all 100% solid and that the ambient potential is zero? Not very good. Hanging a scavenger is a great idea that costs next to nothing.

[MartyGras]

Originally Posted by wpc691

Fixing the fault is the best idea, but we're all surrounded by dozens of docks, lifts and shore power installations. The chances that they're all 100% solid and that the ambient potential is zero? Not very good. Hanging a scavenger is a great idea that costs next to nothing.

There doesn't need to be a fault...when you have two dissimilar metals in salt water it can create electrolysis.

Now add two stainless steel props on one aluminum outdrive and your looking for trouble.

Gary

[wpc691]

Originally Posted by MartyGras

There doesn't need to be a fault...when you have two dissimilar metals in salt water it can create electrolysis.

Now add two stainless steel props on one aluminum outdrive and your looking for trouble.

Gary

Absolutely true, that's why there are so many zincs on modern outboards - I think mine has about 16. But stray currents in the water can drive corrosion way beyond the rate of simple electrochemical couples.

[Macgregorsailor51]

Unless something happens and you or a love one is in the water..... then whats it worth??? Maybe a case or two of Veuve Cliquot

Originally Posted by wpc691

Fixing the fault is the best idea, but we're all surrounded by dozens of docks, lifts and shore power installations. The chances that they're all 100% solid and that the ambient potential is zero? Not very good. Hanging a scavenger is a great idea that costs next to nothing.

[Macgregorsailor51]

Please educate me what Outboard do you own that has 16 zincs on it????

Originally Posted by wpc691

Absolutely true, that's why there are so many zincs on modern outboards - I think mine has about 16. But stray currents in the water can drive corrosion way beyond the rate of simple electrochemical couples.

[SeaRay35]

Wow that a lot my Yamahas only have 4

[wpc691]

Originally Posted by SeaRay35

Wow that a lot my Yamahas only have 4

Sorry, I mis-guesstimated without looking back the list of zincs replaced at the last service. There are either 10 or 6; there are 4 "zinc grommets" on the block - if those are actually grommets made of zinc, then it's 10; if they're just grommets to hold other zincs, then it's 6. It's a Yama F250.

[wpc691]

Originally Posted by Macgregorsailor51

Unless something happens and you or a love one is in the water..... then whats it worth??? Maybe a case or two of Veuve Cliquot

AC leakage around fresh water docks is extremely dangerous, since you're way more conductive than the water; salt water is the opposite, and shouldn't be a shock hazard...which of course doesn't excuse faults. Some quick reading indicates that both AC and DC current leakage around docks and boats are very complicated topics - hard to measure, hard to find and fix problems, etc. Now I'm not sure a scavenger is a good idea - it collects stray DC current, but could also move AC current from a harmless spot to a dangerous one.

Excellent champagne shot, BTW :-)))

[MartyGras]

Originally Posted by wpc691

AC leakage around fresh water docks is extremely dangerous, since you're way more conductive than the water; salt water is the opposite, and shouldn't be a shock hazard...which of course doesn't excuse faults. Some quick reading indicates that both AC and DC current leakage around docks and boats are very complicated topics - hard to measure, hard to find and fix problems, etc. Now I'm not sure a scavenger is a good idea - it collects stray DC current, but could also move AC current from a harmless spot to a dangerous one.

Excellent champagne shot, BTW :-)))

Excellent points about the difference between fresh and salt water.

I'd hate to see what that champagne shot will look like in 15 years.

Gary

[SJNE17]

This thread has been informative. Stuff I'd never heard of.

Maybe dumb question but how can you measure the amount of current in the water dockside to determine if it's a real issue? Between the lift, underwater lights, etc., is it meaningful if the systems are properly grounded?