need wiring help on my old boat

windsurfer77

windsurfer77

Cadet
Joined
Jan 27, 2010
Messages
16
I need to wire up the bow light, and the stern light to an on/off switch, and I want the power to come on to all from my ignition switch.

I can figure this out on a trailor, due to the fact I have the whole trailor for a ground, but obviously in a fiberglass boat this is a bit different.

Can anyone shoot me a diagram of how the wiring should go?
 
seabob4

seabob4

Lieutenant Commander
Joined
Jun 10, 2008
Messages
1,603
Re: need wiring help on my old boat

No, you don't want the ignition switch to be the source of power. Let the ignition switch deal with the engine.

You want to pull hot and ground from the battery, hot running through a 30-40A breaker 7" from the battery, then run to a helm fuse block and a ground bus, which in turn will feed your nav light switch. The ground bus is used for grounding lights on the forward part of the boat rather than running them all the way aft. Plus, that gives you a handy ground under the helm for any future electronics.

Here are 2 ways to wire nav lights...
NavSwitchWiring-1.jpg
 
Lrider

Lrider

Chief Petty Officer
Joined
May 19, 2010
Messages
631
Re: need wiring help on my old boat

Instead of having a metal frame for a ground common you need to run a negative (usually black)(ground) along with the positive (usually red) wire to the light or anything else that would require both wires
 
Bob_VT

Bob_VT

Moderator & Unofficial iBoats Historian
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May 19, 2001
Messages
26,022
Re: need wiring help on my old boat

Lrider said:
Instead of having a metal frame for a ground common you need to run a negative (usually black)(ground) along with the positive (usually red) wire to the light or anything else that would require both wires
Click to expand...

True.... 2 wires to everything ;)

WARNING to anyone who has an aluminum boat....DO NOT USE the hull as a ground...... it will create galvanic havoc in the hull and the aluminum will break down!!
 
J

Jet Star

Seaman
Joined
Mar 14, 2010
Messages
69
Re: need wiring help on my old boat

im planning on wireing my lights that way too with the power coming from keyswitch. im far from an electrician maby thats why i cant make sense of seabob4's diagram the way i was gonna do it was have a wire from "acc" on keyswitch go to an on/off switch then from the other terminal on that switch go to the lights and run inline fuses then have the ground for the lights go to the battery. that would work right? i probably wone do too much night boating and would like to keep in simple as possible
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,762
Re: need wiring help on my old boat

SeaBobs diagram may appear complicated but one must remember that Nav lights are not simply on and off. When under way, BOTH the bow and stern lights must be on. When at anchor, ONLY the stern light is to be lit. Therefore the switch needs to be either a six terminal ON-OFF-ON or a three terminal ON-OFF-ON but this switch would require use of the diode. All too often I see people anchored with both the bow and stern light on. In that scenario you don't know whether they are moving or not. The whole idea of nav lights is to be able to tell movement and direction so you can pass safely.
 
J

Jet Star

Seaman
Joined
Mar 14, 2010
Messages
69
Re: need wiring help on my old boat

i came to that realization after i posted about the nav lights and anchor lights and determined i would need an on of on switch but i dont understand what the diode does? is it needed on the 3 prong switch and not the 6?
 
NYBo

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: need wiring help on my old boat

If you hook the bow and stern lights together to the same switch, there is no way for you to turn on just the stern light for anchoring, as required by the nav rules.

Follow the diagram of your choice as posted.
 
J

Jet Star

Seaman
Joined
Mar 14, 2010
Messages
69
Re: need wiring help on my old boat

ok thanks, i understand it now, simple stuff really, but what size fuses should i run?
 
M

marinetech77

Cadet
Joined
Jun 14, 2010
Messages
20
Re: need wiring help on my old boat

Fuse size will depend on accessory current draw. The package of the item your installing will tell you. Wire size is important also. As in you wouldn't use 10 ga wire for a bow light nor would you use 18ga for a windlass. Use the appropriate size MARINE terminals for the wire your using. They cost more but are well worth it. If using crimp style terminals use a good crimp tool not the one from Autozone for 4$. Do it once, do it right. The ticket from the marine police for no nav lights will cost more than some good wire,terminals,and crimpers.
 
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