Rewiring a steaming and deck light combo

[Lazy Jack 32]

The foremast on the Lazy Jack schooner I've been bringing back to life had a masthead light and, lower down the mast, a combination steaming light and deck light. None of them worked. I just put a new bulb in the masthead light, and replaced the combo steaming and deck light with a new one. Here's the question: the old combo lights had two wires each (one white, one black) going to the deck light and steaming light, but the new one has only three wires--a red one labeled for the steaming light, a blue one for the deck light, and a black one labeled "ground." So, assuming they were the negative wires, I just wired the two white wires running up the mast (one going to the deck light and one to the steaming light) together and attached them to the single "ground" wire on the new light fixture, and attached the red and blue wires on the new combo to each of the black wires that had serviced the old steaming light and deck light, assuming they were positive. The boat is on the hard, the masts are down, and the batteries are out of the boat as we speak, but now I'm wondering what will happen when I try to turn the lights on in a couple of weeks?

Any wisdom will be appreciated.

[deblen]

In normal N.American DC wiring,BLACK is Always Negative.
The other lighter colors (red,blue & white-in your case) are Positives.
Connect the Black(New Lite) To Blacks(Existing cables) & RED & Blue(Lite)to appropriate White(cables).
You can verify the cable color polarity by looking at rear of your fuse & switch panel.
Suggest you buy a $20 Volt Ohm Meter (Tester)-you will need one eventually
Suggest you make sure the lights are working before you stand the mast-much easier.
I believe the lite at top of mast is your All round white Anchor Lite & the one on the lower front of your mast is the MASTHEAD (Steaming) Lite.
Hope this helps. Cheers/Len

[Lazy Jack 32]

Thanks! Glad I asked!

[Spot]

Potential failure modes
-bulbs
-fixtures
-wires in mast
-connections at deck
-wires to switches
-switches
-wires to fuses/circuit breakers
-fuses/circuit breakers
-wires to battery
-battery
-something else draining battery

One hopes it is just the bulb and that fixes it first but if they do not light up after Deblen's instructions you may have to dig deeper.

I have to do the same on mine too, hoping for the best for us both!

[Cyrus Safdari]

Not to be pedantic but despite its name the masthead light doesn't normally actually go on the top of the mast where the anchor light and possibly tricolor go. A masthead light and a steaming light are the same thing, facing forward and showing from dead ahead to 22.5 degrees on each side when vessel is under power. A masthead/steaming light may also incorporate a deck light, as a covenience.

[deblen]

If your mast is down & no connection to boat battery-you can always supply 12v to the wire(s) coming out of bottom of mast from a source such as your vehicle or other source for test of lites. Having the lites actually light up is more reliable than just a continuity test-due to possibilty of corrosion.

[Lazy Jack 32]

Hey, I didn't design the boat, the venerable Ted Brewer did. There is a 360 degree light atop the foremast, and a steaming light a ways down the mast where the USCG says it should be. My problem is that there is a deck light (which the USCG does not require) combined with the steaming light, but only 3 wires to power the both of them.

[StuM]

Originally Posted by Lazy Jack 32

Hey, I didn't design the boat, the venerable Ted Brewer did. There is a 360 degree light atop the foremast, and a steaming light a ways down the mast where the USCG says it should be. My problem is that there is a deck light (which the USCG does not require) combined with the steaming light, but only 3 wires to power the both of them.

You only need three wires, the two lights will have a shared negative (ground).

You've apparently wired them the wrong way round.

Grab a 12V battery (or a long lead from your vehicle).
Attach the black wire to the negative terminal on your 12V battery.
Connect the red and blue wires one at time to the positive terminal. If both lights work at the appropriate time, connect both at the same time to the battery positive. If both lights come on, then it's all working as designed.



The red and blue wires should be attached to the appropriate white wires. The black wire to either or both of the existing black wires



And as others have pointed out the "steaming light" is your "masthead light" IAW COLREGS.


The "light at the top of the mast" is your "all round white light" for use as an anchor light.

[Spot]

Small 12v battery and test leads to test a light...
Schematic may be something like this:

[Kelkara]

Just want to point out that Black isn't *always* negative. The original 1975 wiring in my boat was white/black, and black was positive. So before you wire the two black wires together, it might be worth double-checking to confirm they are indeed the negative wires.

[Spot]

Originally Posted by Kelkara

Just want to point out that Black isn't *always* negative. The original 1975 wiring in my boat was white/black, and black was positive. So before you wire the two black wires together, it might be worth double-checking to confirm they are indeed the negative wires.

True, true... the pairs of wires going to the mast/lights could be checked for polarity with a multi-meter set to 20VDC (assuming 12VDC)once a battery is back in the boat, fuses are sound, and the proper switches are turned on. One would also see if power is getting from battery all the way to the mast.

[deblen]

Originally Posted by Kelkara

Just want to point out that Black isn't *always* negative. The original 1975 wiring in my boat was white/black, and black was positive. So before you wire the two black wires together, it might be worth double-checking to confirm they are indeed the negative wires.

You are correct. I should have said Black should always be Neg in N.A. DC



It was probably reverse wired by an "AC" electrician


Your black should have been Neg & the black/white(lighter color) should have been positive.
No harm-yours isn't the only one. I've seen more.


Cheers/Len

[Lazy Jack 32]

Thanks, all. I'll take a battery out to the boat and see what's what.

[KP44]

Originally Posted by Lazy Jack 32

The foremast on the Lazy Jack schooner I've been bringing back to life had a masthead light and, lower down the mast, a combination steaming light and deck light. None of them worked. I just put a new bulb in the masthead light, and replaced the combo steaming and deck light with a new one. Here's the question: the old combo lights had two wires each (one white, one black) going to the deck light and steaming light, but the new one has only three wires--a red one labeled for the steaming light, a blue one for the deck light, and a black one labeled "ground." So, assuming they were the negative wires, I just wired the two white wires running up the mast (one going to the deck light and one to the steaming light) together and attached them to the single "ground" wire on the new light fixture, and attached the red and blue wires on the new combo to each of the black wires that had serviced the old steaming light and deck light, assuming they were positive. The boat is on the hard, the masts are down, and the batteries are out of the boat as we speak, but now I'm wondering what will happen when I try to turn the lights on in a couple of weeks?

Any wisdom will be appreciated.

Where to begin?

The code for AC wires does not hold for DC. In marine wiring we use yellow for ground wires and older wiring used black for ground.

You will be wise to pull new wires now, while your mast is down. You need two wires to the mast top for your all-round anchor light. Use red + and yellow - if possible. Or yellow and anything except black.
You need 3 wires to your steaming/deck lights. Again use yellow for ground.

Take a battery and test your wiring. Make sure you have it right before that mast goes up!