For the shore power A/C power.........Needed or nice to have?
I'm an EE and it sounds like BS to me
I'm an EE and it sounds like BS to me
Galvanic isolators
- Thread starter mjmercer19248
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Lots of us, including me, who normally connect to shore power have had galvanic corrosion issues related to stray current on the shore power ground which caused damage to underwater metals including my expensive prop. As an EE, you can easily understand a couple of diodes which are the fundamental component of these isolators can eliminate the problem.
In that scenario, the surface area is so large as to make it unlikely anyone would notice for a very long time. Regardless, think of a boat as a battery with one side connected to the electrical system on board and the other to shore power. With an aluminum dock, you are missing one "side" of the battery.we have aluminum docks with ladders at our marina......if there where any stray power.........would it not eat the ladders......I dont want to steal this post.......but it could be good timing
one of those things that you should have IF you need one on the boat.. It is not too expensive a "just in case" thing and it does no damage if you don't need one.. but if you need one and don't have one, you'll end up with underwater things disappearing .. like propellers and struts and possibly thru-hull fittings.. A way to find out is to do (or have done) a galvanic survey on the boat in the slip.. or mooring .. Nigel Calder has some good articles about what and why.. As Don says, it is normally not your boat but stuff around you that causes the need..
When you plug into shore power you are connecting the the ground circuit in the AC lines on the dock. So does anybody else that connects to shore power. The interconnection of all those boats is the problem. Odds are that there is some underwater metal on someone's boat that is incomparable with your underwater metal. When you connect the two you get corrosion. There are three solutions. Only use gold underwater. don't connect to shore power or get an isolator.
Its well worth it from my perspective, I had to haul out and repaint when all the bottom paint was blown off the keel, I hope it didn't eat too much off the bolts, ha ha. I also had to replace the prop shaft last trip out of the water, the electrolysis caused the shaft to basically delaminate. One whole outter coating of metal came off like it was really thick bottom paint, but it was metal flaking off the shaft. Heck, I just heard that there are good ones and so-so galvanic isolators, I'm thinking I might be upgrading soon.
Kb
Kb
- Aug 10, 2010
- 115
- Aug 10, 2010
- 115
I just learned that they make a galvanic testing probe. It plugs into a digital multimeter and goes into the water, and the other lead goes to your engine ground/bonding ground. The dockmaster ended up testing many boats in the marina at the dockside powercord when we were all gone so see who might be leaking. Really cool and it helped us to learn a little more about our boats.
Kb
Kb
OK, so here is another question. Shaft strut is bonded to engine and keel bolts. That is all the metal I have in the water except for the shaft/prop. Cutlass bearing is rubber, connection to the egine is through one of those vibration proof couplings (rubber, no electrical connection to the engine)
I suspect the shaft/prop should be bonded, any suggestions on how to acheive that?
I suspect the shaft/prop should be bonded, any suggestions on how to acheive that?
You can jumper across the bolts with #8 wire. This will meet the ABYC standards or install a shaft brush.
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