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Discussion in 'Other Repairs' started by kevinw, Oct 22, 2005.
Can I use the aluminum boat hull for my negative ground like an automobile?
good Q. i was putting a bilage pump in mine and wiring up the front and rear lights. when i accidently touched the + wire that was going to a toggle switch to the pump that was coming off the battery and the other side going out to pump it came on. so it should work. just don't know if its the right way or safe. better wait for someone that knows first. im not sure.
Yes, but you may experience a problem called electrolisis (sp) .
Basically corrosion at the electrical connections to the hull.
You may also experience disimillar metal corrosion. (ie copper terminal to aluminum hull).
I wired my boat with a two wire system and have had no problems.
I also used a battery connection protection spray on all of my connections, available at NAPA. 3 years in high humidity and no problems so far.
I hate working on my boat on the water, so I do everything to avoid it.
There ain't no maybe about it. Never use your boat hull for a ground.
Electrolosys will pop holes in your aluminum faster than you can plug them up.
Thanks.. Thats what I needed to know.
sounds like a two wire system is the ticket. thats what i did in my lil 10'er i just wired up with the lights and pump.
been there done that the guys are 100% right never use hull as ground 2 wire is the way to go one to pos the other to neg on BATTRIE,
I have a mid '70's Lowe jon boat (14ft) that has been wired that way for years, no problems at all. I have two batteries under the center seat, they ground to the hull under the seat. There is an insulated positive block at the transom with a flip-up cover for connecting a trolling motor or whatever, the gas motor is electric start and is connected to this block and grounded to the transom. It doesn't leak. Not saying it won't, but it hasn't yet. If you are just using the hull as a ground conductor, there would have to be stray positive current flowing in the water before any reaction would occur. In your local river, I doubt this would be a problem. Now, in a lake, especially around docks with shore power, this is a big issue.
The problem occurs with electrolosys quickly in salt water and the coastal black water rivers of the east coast. High mineral content.
When it starts there is no reversing it.
It never fails that when I give a positive to a question there are always those that want to shed some doubt on the answer.
Ya'll do what you want, I'll two wire all my boats.
bob, doubt comes from those who have almost no knowledge of boats and don't have a clue how electricity
There are some many wrongs to not using a "2 wire system" that it'd take me half the day to type them all out.
Ponder this, Do ya like sparks around gasoline?
Do ya want to run the risk of ruining your boat?
Do ya want to chance getting an electrical burn?
Cool. Stick to using a 2 wire system.
ill stick to a marine mechanics advice, lol.
Bob, I wasn't trying to shed doubt on your answer, just stating facts. My boat is wired this way, was like that when I bought it, has been for years, and doesn't leak. The comment I made on the electrolysis came from an article that I researched on the net before replying to your post. I wanted to know if it was going to be a problem after reading the original post so I looked it up. There has to be positive current flow to cause a problem. I am an auto tech and have seen electrolysis in cooling systems usually due to the coolant flowing between two dissimillar metals (thats how a battery works) and stray currents resulting from poor grounds. There again, it is due to stray current. If there is no positive current in the water, it can't harm anything unless you have current escaping your boat into the water. That is why this is such a big problem at marinas with docks that have shore power. At Kerr Lake here in NC, my wife's parents have a houseboat on a dock with shore power. The marina doesn't allow swimming anywhere near the dock for this reason.
Keith, My reply or doubt did not come from having no knowledge of boats or electricity as I deal with MAJOR electrical concerns on a daily basis on today's vehicles, and have been doing this for 17 years. There are miles of electrical circuits and numerous control modules on newer cars and you have to know what you are doing to find and correct the problems without creating another. I will never disagree with you on a plumbing issue though as I am clueless when it comes to that. Well, other than hot on the left, cold on the right and crap flows downhill.
aint nothing i can ad to this one been answered lol. ive always dual wired all my boats and seen some using the haul for a ground bad mistake saw a guys boat go up because it sparked near the tank if he had dual wires wouldnt of ever happened
Kittyhunter, you cleared that up pretty well.
Aluminum and the minerals in the water are your dissimilar metals. Put the probes of an amp meter in the water out of your boat that'll read milliamps and it'll register some. Stray current.
Put an aluminum boat in a dirty river and it'll eventually corrode. Add the flow of electricity through the aluminum from a battery and your asking for trouble.
I can't really say why the batteries in your boat haven't fallen through the hull yet, but i'm pretty sure the aluminum in your boat ain't what it used to be.
I agree dual wiring is a better solution, just saying mine has been like that for a while with no problems. I didn't wire it, it was like this when I bought it and I haven't changed it yet. I plan to redo my whole boat this winter and will go with dual wire system. Even with a dual system you can still have sparks (poor connections at the battery will spark) and with your battery close to the tank, you will have problems, I agree. My batteries are under my center seat well away from the tank. I do have a positive junction block and a ground for the starter at the back of the boat and I keep the connections checked for corrosion or looseness. I was not saying this was the way to go, just that it could be done.
LOL!! Bob, I can't answer that either, but she's over 30 years old and doesn't leak a drop. I filled it with water this year to check the rivets and it's as tight as it ever was.
I'll take my meter next time I go to the river and try that out.
LOL the plumbing is just a sideline thing.
My whole point was to explain the entire issue of saftey. I've dealt with AC and DC systems for over 20 years. From the "high lines" down to a simple 3.4 volt battery.
DC voltage is very unforgiving. I've seen guys not take heed in a UPS room attaching cables and series ing battery towers together and get slam ate up.(480 volt battery banks)
Thats the thing, you have to be very careful when explaining what you know to a person who'd be considered a novice. With some many installing dual battery systems in their boats, it leaves just too much too chance.
I'd never use anything but a 2 wire system for several reasons. The biggest being resistance. The aluminum boat has more resistance than a coated , stranded, copper wire. (remember that electricity travels on the surface of a conductor).
This being said, a covered copper, stranded wire would be not only a better conductor,but, a safer one also.
This was just another post probably worded wrong. Thats my point for discourging a boat to be used as a ground.
The loose,bad, and improper connections, will be overcome by proper fuse sizing for each and every piece of equipment. Thats 1 more thing, I always, always, run a seperate wire and fuse for each item on my boat.
Hope this helps out,