Mast head lights idea

[Alpha22]

Would this work??

I have a short mast on my mobo, there is only a twin plug on the deck and only a twin core cable running up the mast. Currently there is only an anchor light and I would like to add a steaming light on the mast.

I had the idea to use LEDS for the lights, one forwards and the other in reverse polarity. Then use a DPDT change over relay to reverse the polarity.

See picture - would it work??? Is there a better way to do it without running another cable?

 

[prv]

The reverse-polarity idea is a standard dodge and should work fine, but the relay mechanism seems overcomplicated to me. You can buy DPDT centre-off switches in many styles, just use one of those.

Pete

 

[VicS]

Is there any reason why you cannot simply use the all round white light as:

A combined steaming and stern light in conjunction with port and starboard lights when underway

On its own as an anchor light

Or are you over 12m LOA

The idea of reversing the polarity if you must have two lights may or may not work. I think you will find that some LED nav lights are not polarity sensitive!.
I am pretty sure the one I fitted is not!

 

[chewi]

The changeeover switch would be simpler as a center off, the other way round.
Then using the two commons to the light you could connect your reversed polarities to each of the poles, so dispensing with the single switches, and as said elsewhere the relay is OTT, as is perhaps the whole idea if a small boat as also suggested above.

 

[Rigger Mortice]

The idea of reversing the polarity if you must have two lights may or may not work. I think you will find that some LED nav lights are not polarity sensitive!.

Good point!
I suppose that you could bung a diode in the circuit to make it polarity sensitive.

 

[Alpha22]

Thanks for the feedback....

The boat is a 1966 Freeman 30.....

2 switches - I want to use the classic Freeman ball ended toggle switches so it matches the rest of the 'classic' dash. There is not a matching 2 position centre off switch otherwise I would use it....

2 lights - i know I could get away with it under col regs, but again, I found a period stemming light at Beaulieu last year and want to fit it!!

So it looks like the basic theory is sound. I would make my own bulbs from scratch so no problems with polarity 'safe' LEDs. I appreciate there needs to be a dropping resistor in there somewhere too, but it is possible..... thanks again.