Stern light (wiring) question -Sealine F42/5

[sniffer]

Whilst fixing my stern light I am a little confused about the wiring setup. The light is the original 2003 Aqua Signal unit with a BAY15D (D for double) socket. I understand that the bulbs for these types of fitting have 2 filaments (like in the automotive world, where one is for tail light and one is for brake light for example) and each filament is connected to it's own contact connector on the bottom of the bulb. Each filament is also connected to the metal body of the bulb.

Anybody any idea why is this setup used for a stern light that only requires a single bright light? It's prticularly weird to me as the wiring diagram and the actual wiring of the boat only has two wires, pos & neg.

Fitting a new BAY15D bulb results in a not so bright bulb. This is also the case if I apply 12v directly to the two contacts of the bulb whilst out of the fitting (regardless of polarity), which is what is effectively happening to an installed bulb. If I apply neg to the bulb body and 12v directly to each bulb contact in turn I light each filament in turn with the bigger contact being really nice and bright.

Can anybody help with my confusion?

Edited just to say, neither of the two wires is connected directly to the body of the bulb via the Aqua Signal unit.

Cheers,
Mike.

 

[Pinnacle]

For nav lights the filament needs to be vertical. I suspect you need something like this - https://www.sparkswarehouse.com/pro...MIq4nMw7SVlAMVq7GDBx0h1wF3EAQYFCABEgL2PvD_BwE

 

[sniffer]

For nav lights the filament needs to be vertical.

Interesting. What difference does the verticality make? Is there a different internal electrical layout to these bulbs?

 

[PaulRainbow]

Whilst fixing my stern light I am a little confused about the wiring setup. The light is the original 2003 Aqua Signal unit with a BAY15D (D for double) socket. I understand that the bulbs for these types of fitting have 2 filaments (like in the automotive world, where one is for tail light and one is for brake light for example) and each filament is connected to it's own contact connector on the bottom of the bulb. Each filament is also connected to the metal body of the bulb.

This is incorrect. The D stands for "double contact" not double filament. Your nav light should have a single filament bulb in it, post #2 shows an example. The automotive bulb you have will not show the light correctly, either wrong range, wrong sectors or who know what. It's just wrong.

Anybody any idea why is this setup used for a stern light that only requires a single bright light? It's prticularly weird to me as the wiring diagram and the actual wiring of the boat only has two wires, pos & neg.

Fitting a new BAY15D bulb results in a not so bright bulb. This is also the case if I apply 12v directly to the two contacts of the bulb whilst out of the fitting (regardless of polarity), which is what is effectively happening to an installed bulb. If I apply neg to the bulb body and 12v directly to each bulb contact in turn I light each filament in turn with the bigger contact being really nice and bright.

Can anybody help with my confusion?

Edited just to say, neither of the two wires is connected directly to the body of the bulb via the Aqua Signal unit.

Cheers,
Mike.

You just need to fit the correct, single filament lamp and connect positive and negative to the two spade terminals of the lamp itself. There should be no connection to the lamp holder itself.

 

[sniffer]

This is incorrect.

No it's not, not in the context I was refering to.

You just need to fit the correct, single filament lamp and connect positive and negative to the two spade terminals of the lamp itself.

I did, from Force 4 Chandlery and that is what lead me down the rabbit hole, as the bulb is not as bright as it should be.

There should be no connection to the lamp holder itself.

As I said in my original post, there isn't.

Thanks for easing my confusion.