Masthead strobe without running another wire?

[sanibel sailor]

I currently have an Aquasignal masthead tricolor and anchor light combo. It has a built-in strobe that is not currently wired.

There is a technique (outlined in The 12 Volt Doctor's Handbook) to have both an anchor light and a tricolor separately on just two wires using a DPDT switch that reverses wire polarity and diodes at the masthead that send the voltage to the right fixture. I was going to post the schematic, but cannot locate my book at the moment.

My current light is a little trickier as it has two hot leads for anchor and tricolor and one common negative. The strobe uses the same negative. Does anyone know if a similar trick is possible without running another wire to the masthead? A simple schematic would be great.

[sanibel sailor]

Here is a schematic for the simple situation

[sanibel sailor]

No responses, must be impossible!

Here is the page out of the book I was looking for. I used it to come up with my proposed solution.

But my solution won't function correctly I believe. Power applied to tricolor will illuminate all 3 lights. I cannot figure out a different wiring scheme.

Any electrical engineers out there?

[Badsanta]

Over my head, sorry

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[Sun and Moon]

I assume you currently have 3 wires going up your mast: 2 positive wires on switches to turn on your tricolor and your anchor, and one common negative. If you have only two wires running up your mast you can't control 3 lights.

If you have 3 wires your solution is simple: wire the existing lights using the 2-wire solution for filament. That leaves you with the third wire free (and presumably already wired as switched positive lead). Connect that to the positive lead on your strobe and connect the negative lead on the strobe to either of the DPDT leads coming up the mast. The lead you pick will be either a) negative b) positive or c) disconnected, depending on how your switches are set down below. Setting the DPDT switch so your chosen lead is negative, and energizing your positive 3rd lead will energize your strobe.

So if your switches are:
Sw #1 - DPDT positive
SW #2 - Strobe positive

To turn tricolor or anchor on, turn on switch #1 and turn off switch #2. Use DPDT switch to choose which light is on.

To turn strobe on, turn switch #1 off, turn on switch #2 and set DPDT switch to one side or the other. One will turn strobe on and the other will turn strobe off.

You can have either the tri-color or the anchor on along with the strobe, depending on which DPDT lead you chose at the top of the mast, by turning on both SW #1 and SW #2.

Turning off SW #2 will always turn the strobe off.

[Sun and Moon]

Of course you might as well start a thread right now for the next owner to complain about the un-understandable mess the previous owner created with the masthead wiring

[model 10]

Use a wireless or blue tooth relay.

[sanibel sailor]

I think I understand what you are suggesting. I do better with pictures. Could you draw a schematic. Thanks.

Originally Posted by Sun and Moon

Of course you might as well start a thread right now for the next owner to complain about the un-understandable mess the previous owner created with the masthead wiring

I have made color coded wiring diagrams for everything on the boat, but really more to suit forgetful me than the next guy. It is better than the crappy one from Westerbeke for instance.

[Sun and Moon]

Here's a wiring diagram. I've added two diodes to the Strobe circuit. Now Switch 1 turns on and off the Tricolor/anchor (DPDT selects which), and Switch 2 turns the Strobe on and off. Strobe and Tricolor/Anchor are independent of each other.

[sanibel sailor]

Thank you for stimulating my thought process. Here is a potential solution that keeps my existing breaker panel switches, adds a single DPDT on/on two position switch (I would envision one with a race car style cover that keeps it in the "anchor" position) and a relay to ground one wire for the tricolor. The only downside I see is that if the anchor light is turned on when the tricolor is also on, that there will be a short to ground, tripping the breaker.

I could use a DPST switch for the tricolor and its ground circuit, eliminating the relay, but then it will be a second switch besides the panel breaker.

[monte]

Gotta ask, why do you want a masthead strobe light?

[cabo_sailor]

Monte ,

I have to agree with you. I had a masthead tricolor/ anchor light/strobe for the last 15 yrs. I've used the strobe only once for about 30 seconds to let a freighter know who was talking to them. Birds have destroyed that light and it will be replaced in a couple of days with the simple tri-color anchor light. Adding the strobe is a cost I can't justify.

Rich


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[sanibel sailor]

Originally Posted by monte

Gotta ask, why do you want a masthead strobe light?

Boat came with just an anchor light. When I had the mast down, I replaced the old wire with a 3 conductor cable, expecting to install a anchor/tricolor combo someday. Came across an unused tricolor/anchor/strobe combo at a flea market for $100. Would not generally have paid the extra several hundred for the strobe feature otherwise. Light is now installed and working except for the strobe. If I can make it work with a switch/relay without running another wire, it is worth having.

[monte]

Ok. I installed a 5 way anchor/nav/strobe/fast strobe/vertical light that came with the option of using 2 wires for anchor and nav, or running an additional wire and switch for the additional features. I stuck with the 2 wire nav/anchor light combo as that was the reason I bought it (anchor light is automatic at dusk/dawn). No regrets, I can't imagine ever wanting the strobe features. Cost was about $250 for the light

[Muckle Flugga]

Originally Posted by sanibel sailor

Boat came with just an anchor light. When I had the mast down, I replaced the old wire with a 3 conductor cable, expecting to install a anchor/tricolor combo someday. Came across an unused tricolor/anchor/strobe combo at a flea market for $100. Would not generally have paid the extra several hundred for the strobe feature otherwise. Light is now installed and working except for the strobe. If I can make it work with a switch/relay without running another wire, it is worth having.

Not trying to be a miseryguts about it, but technically a strobe is not a legal light. In fact, it irritates me no end when I see people using strobes at anchor, particularly white strobes, as they are identical in sequence to North Cardinal marks… I'd just leave it unwired.