aluminum boats and battery ground
Erebus100
Is there really a reason that the hull of an aluminum boat shouldn't be
grounded to battery negative? It would make for much easier wiring since you
wouldn't have to take wires far to find ground. Certainly I can't see any more
shock hazard than with a car. The big puzzle for me is how does it affect
electrolytic corrosion?
Any ideas?
Jralbert
In article <19980204072...@ladder02.news.aol.com>, ereb...@aol.com
(Erebus100) writes:
>ubject: aluminum boats and battery ground
From: ereb...@aol.com
>(Erebus100)
Date: 4 Feb 1998 07:21:20 GMT
-------------------
Hmmm.... i believe my aluminum-hulled "Marinette" cruiser does have the
battery negative grounded to the hull. If electrolysis were a problem, the
boat would have fizzed away by now, like an Alka-Seltzer tablet. The subjects
of electrolysis (*though I understand the basic principle), grounding, and
bonding make my brain freeze and eyes glaze over. I've made the mistake of
listening to too many experts (with differing takes on their expertise). I
just know it's scary stuff, dangerous to the health of the boat if you get it
wrong.
Joel Albert
Potomac, MD
((jral...@aol.com))
Bryon Kass
Talk to any metal boatbuilder and they will agree that this course
can increase corrosion. There have been cases of boats sinking from
this phenomena.
Bryon Kass
webmaster and
Custom Design
150 Mechanic St.
Foxboro, MA 02035
508-543-9068 or fax 508-543-5127
in THE ENGINE ROOM http://www.ici.net/customers/cusdn
Erebus100 wrote:
>
> Is there really a reason that the hull of an aluminum boat shouldn't be
> grounded to battery negative? It would make for much easier wiring since you
> wouldn't have to take wires far to find ground. Certainly I can't see any more
> shock hazard than with a car. The big puzzle for me is how does it affect
> electrolytic corrosion?
>
> Any ideas?
Charles and Linda Bender
I wouldn't even attempt to claim any expertise in this
area. But I know a little about under ground fuel lines on
a military air base having what is called cathodic
protection. Which is a light charge of electricity run
through it to prevent corrosion. At least the air base in
our town has this system.
I have no idea if this would work in the case of a boat in
water. The way I understood the principle, if I remember
correctly. The current running through the metal, lines up
the electrons and improves the nobility of the metal by
keeping the electrons in their places with the charge.
Which I also understand is the principle of the sacrificial
anodes on the anticavitation plates and other places on an
outboard or stern drive. They are less noble metal (zinc)
which means the electrical charge leaks through them and
electrons vacate and deteriorate the anode, leaving the more
noble metals of aluminum and stainless steel, which are
flowing the current through them to the sacrificial piece.
This is just my interpretation of someone else's explanation
of this system. I claim no real expertise in this area. It
just made sense to me, when I heard it.
My $.02 worth,
Charles
fred
Erebus100 wrote in message
<19980204072...@ladder02.news.aol.com>...
>Is there really a reason that the hull of an aluminum boat shouldn't be
>grounded to battery negative? It would make for much easier wiring since
you
>wouldn't have to take wires far to find ground. Certainly I can't see any
more
>shock hazard than with a car. The big puzzle for me is how does it affect
>electrolytic corrosion?
>
>Any ideas?
Well, remember the lovely experiment about 30 years ago with aluminum
wiring? The problem with it is that the connections would corrode causing
extra resistance, which cause a fire hazard.
While I'm not suggesting it would set your boat on fire, but it could cause
problems if you lose electrical ground at the wrong time.
Quick quote from "Residential Wiring for the 1996 NEC" by Markell (Wow, an
actual bibliography in usenet, what a concept" -- "All in all, the general
consensus amoung people in the electrical field is that the best possible
thing to do with aluminum wire is _nothing_. Avoid using it if possible."
What would I connect using the an aluminum ground? Only something I didn't
really need. Keep in mind that if you hook a copper wire to aluminum, you
have to put the anti corrosion gunk on the connection.
If you are pulling the positive wire, you might as well pull the negative
one too.
Unless they come up with a copper boat. It would be pretty, but I sure
wouldn't want to hit a log with it. :-)
Ron14th
>Well, remember the lovely experiment about 30 years ago with aluminum
>wiring? The problem with it is that the connections would corrode causing
>extra resistance, which cause a fire hazard.
> Keep in mind that if you hook a copper wire to aluminum, you
>have to put the anti corrosion gunk on the connection.
The truth of the matter is, you must use the oxiban (gunk) for any alum.
connection, Copper to alum, or alum to alum, and the torch of the connection
must be maintained. In short don't do it. It will cause the alum in the boat at
the joints to oxidize much faster!
Happy Boating
Ron T.
Bill McKee
My Alum boat uses the alum hull for ground. The copper ground wire is
terminated in a ring connector and attached to the hull. There would also be
grounding from the engine to the hull via the drive shaft and jet drive.
Admitted its a trailer boat, so does not live in the water between uses. This
is a very expensive, high quality boat, so they would have run separate grounds
if needed. The problem with the Aluminum wiring in homes was the connectors
came loose and oxides built up causing a resistance connection, therefore
heat. The connectors came loose as the aluminum was in the plastic region as
opposed to the copper when it was tightened being still in the spring region.
The alum would deform and allow the connection to loosen with temperature
changes.
Regards, Bill
fred wrote:
> Erebus100 wrote in message
> <19980204072...@ladder02.news.aol.com>...
> >Is there really a reason that the hull of an aluminum boat shouldn't be
> >grounded to battery negative? It would make for much easier wiring since
>
> Well, remember the lovely experiment about 30 years ago with aluminum
> wiring? The problem with it is that the connections would corrode causing
> extra resistance, which cause a fire hazard.
>
> While I'm not suggesting it would set your boat on fire, but it could cause
> problems if you lose electrical ground at the wrong time.
<snipped>
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bill
As person that does control wiring for a living and also owns an
aluminum boat that is in the process of being rewired. I would suggest
the use of a negative hull ground but I would also mount a Copper
ground Buss for all returns on stainless bolts and not use the hull
as a return path, Two reasons, # 1 you do not want to induce
currents thru the hull , It may deminish hull protection systems. #2
connection bonding, aluminum - copper connections are going to be a
source of problems.
AZBill
Ron14th
AZbill I agree with you 100%. I am in the same trade.
Happy Boating
Ron T.