ground to hull on aluminum boat?

BF

Lieutenant
Joined
Apr 8, 2003
Messages
1,489
Hiya,

I just bought a project boat.. basic tiller steer fishing boat. It does have lights and a bilge pump (all maybe trash, but I don't know yet). It does have a storage compartment for a battery, and I'm intending on putting a fish finder on it. So, rather than power the finder from a battery pack, I'm gonna re-wire the boat to get the lights operational, maybe replace the bilge pump, add a horn, and run the finder off the real full-size battery.

Straightforward enough stuff... I'll add switches for the stuff at the back end, and probably make a little compartment under one of the seats at the stern for a small fuse box.

Question: On an aluminum hull, do you tie the negative battery terminal to the hull, and then ground all your lights, bilge etc just to the hull, or do you run duplex wire to everything and ground it to the negative battery terminal and leave the hull un-connected to the negative terminal?

The boats that I have that have electric's are all fiberglass, so have dedicated runs for the return path that are connected to the negative battery terminal. From the wiring that's left on this aluminum boat, it looks like the lights were just grounded to the hull... but maybe there's a reason why it's best not to do it that way (?).

Thanks!
 

burroak

Senior Chief Petty Officer
Joined
Mar 29, 2007
Messages
651
Re: ground to hull on aluminum boat?

I don't think you want to use the hull as a grounding source. Every ground should be home run to the (-) post or to a distribution block dedicated to grounding all circuits.
 

johnson1989

Petty Officer 2nd Class
Joined
Apr 16, 2007
Messages
110
Re: ground to hull on aluminum boat?

Yes definatly run a home run to the (-) of the battery terminal and then run the rest of your grouds off that. The Hull of the boat would not be the best spot to ground
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: ground to hull on aluminum boat?

run all your stuff off the fuse block to switch, to fixture ground back to buss bar. then you can run the main feed and ground to the block. here's a simple but good little fuse block, buss bar combo. Left side is the ground buss bar, the right side is the feed + buss bar, the individual lines run of the 4 center screws.
http://www.iboats.com/Seasense_Fuse...67666603--list_time.1177378278--view_id.56052
 

BF

Lieutenant
Joined
Apr 8, 2003
Messages
1,489
Re: ground to hull on aluminum boat?

thanks folks... yes, makes sense to run a dedicated ground/return for everything... thanks takahashadaddy, yes, that's the kind of thing I was thinking of. Maybe put it in some kind of box.
 

burroak

Senior Chief Petty Officer
Joined
Mar 29, 2007
Messages
651
Re: ground to hull on aluminum boat?

I don't know how involved your wiring plan is; however, I have a wiring diagram for aluminum boats. It includes all the circuits needed to run a boat and then some. If you want to PM me with your e-mail address, I'll send it to you as an attachment. If anyone knows how to post it on iboats (I'm just not clever enough to do it), I'll send it to you for you to post. It is has specific sub-diagrams for OMC products; even so, it should help many who have a complete rewire to do.
 

Skinnywater

Commander
Joined
Mar 7, 2002
Messages
2,065
Re: ground to hull on aluminum boat?

I just completed extensive wiring to my aluminum boat.
Do get the marine dual conductor bonded wire. It's reasonably priced and makes it neat and simple.
 
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