Crazy ground idea

[polk county]

If a boat trailer is the common ground for all trailer lights why can?t an aluminum boat be the common ground for all boat electronics? For instance, instead of running a ground wire from each electronic device why not just ground the negative leads of the electronics to the boat. (Using rings snaps and stainless screws) The negative post of the battery will be in turn grounded to the aluminum boat. This would allow current to run through the boat back to the negative post, thus completing the circuit. This would eliminate the need to splice all electronic devices to a common ground wire. Instead the entire boat is the common ground wire. I think this is the way automotive electronics work. The bumper of my truck will light up my circuit tester. I?ve already tried it on my 16 ft aluminum john boat and it works. Does anyone see any problems with this? Will it interfere with the sacrificial anodes?

Ideas are appreciated.

 

[Silvertip]

Re: Crazy ground idea

If you run in salt water you will quickly find out why that's not a good idea on a tin boat. Fresh water not so bad. There are all sorts of stray currents going on in a boat when placed in the water. Shore power at the dock is a contributor to corrosion issues. Actually, the engine gets bonded to the hull by the engine mounting bolts but electronics in a boat have dedicated grounds. Cars and trucks do not live in the water (generally) so grounding is not as much of an issue. That said, vehicles today must also pay more attention to grounding than in the past since electronics are more sophisticated and grounding issues can create problems. Common ground is simply a better way to do things.

 

[Wreck Rider]

Re: Crazy ground idea

Not a crazy idea at all but there are some small problems with an aluminum boat. Silvertip already mentioned a couple, and there's also the simple idea that bonding copper to aluminum is going to result in local corrosion no matter what. Using stainless snaps like you suggest will work but the junction between stainless and aluminum will corrode no matter what because of the very different electrical properties of the metals. Current running through the hull will help corrode and loosen all the rivets too!

Chemistry theory (for those interested)
We think aluminum doesn't corrode in everyday life, not like steel, but it actually does, and much faster than steel.

The difference is steel corrodes to form a flaky and porous coating of rust that traps moisture to accelerate the rusting, but doesn't protect the steel at all.

Aluminum in air at room temperature will almost instantly corrode as soon as a clean pure aluminum surface is revealed, like when you scrape it with a knife, or by accident on a dock. The difference is that the aluminum oxide forms as a nice thin, strong layer that bonds well to the underlying aluminum and seals out oxygen so it stops further oxidation.

 

[jtexas]

Re: Crazy ground idea

not to mention which, if you're fishing, you want to minimize your electromagnetic signature.

 

[bhammer]

Re: Crazy ground idea

We think aluminum doesn't corrode in everyday life, not like steel, but it actually does, and much faster than steel.

Great point!

One of the biggest maintenance factors in aging aircraft (the majority of them flying today are aluminum) is corrosion. The majority of metals will eventually turn back to their natural state.

If you do find an area of corrosion, you can etch and alodine the area to stop it. Most metal shops will give you some if you ask. This puts the "protective layer" back on.

If you want to watch aluminum corrode fast, then just drop some mercury on it. In a couple hours to days (depending on the type of aluminum) you will see the result. Just make sure you capture all the mercury as the EPA will get mad.

 

[External Combustion]

Re: Crazy ground idea

Using the hull as a ground for all of the equipment on board turns it into a "floating ground" who's potential rises and falls a few volts with what equipment is on or off and what metal in the galvanic series is touching it. Anything other than zero potential will cause the hull to become an anode or a cathode, either accepting electrons or giving them up, thus becoming less of a metal that it should be.

A true grounding buss bar takes the hull out of the loop and it lasts much longer.

 

[Bondo]

Re: Crazy ground idea

Ayuh,....

As noted,.... If you use the hull for a Ground path,....
It'll turn to Dust in No Time Flat......