Peter,
I have not done this yet but I plan to someday.  The attached diagram shows how I would do it.  Essentially Y'ing the 2 mast wires at each end and attaching to a Dual Pole Dual Throw (DPDT) switch and wiring the lights in with opposite polarity.  Since the lights are not grounded to the mast in any way there should be zero impact to any other electrical systems.  You do need a DPDT switch that includes an off position OR use another switch (or existing switch) in front of it to provide the OFF function. Otherwise, in my diagram, one light is always on.

If someone that has already done this sees an error please let us know.

Patrick



DPDT_for_MastWire.pdf

On Wed, May 6, 2026 at 2:44 AM peter beckerman via Rhodes22-list <
rhodes22-list at rhodes22.org> wrote:

> Hi All,
> Happy to see the site up and running, I was afraid it might be gone for
> good.  For one of my spring projects, I'm looking to add an anchor light.
> I have heard of folks using two polarity reversed LEDs for steaming and
> anchor lights thus eliminating the need to run a whole new wire up the mast
> or adding or replacing the deck fitting.
> This idea appeals to me (especially  not messing with the deck fitting).
> I'm sure this approach will work in a closed system (just a battery and the
> lights), but I'm worried about creating a short circuit in a more complex
> system (lights, radio, depth sounder etc).  Does anyone have experience
> doIng this with a complex system or can anyone explain how it a doesn't
> create a problem (assuming it doesn't).
>
> Thanks,
>     Peter
>
> [ Sent From rhodes22.net ]
>
>