Brass head lamp

[alan_fincher]

19 minutes ago, Alan de Enfield said:

I did not suggest, or even allude to, the fact it would be a 'fail'.

Irrespective of the BSS, it is not a good idea (electrically) to use the hull as a 'return'

Unless I'm missing something obvious, I don't understand why it is in the BSS at all - surely it is not a major safety consideration, and the BSS doesn't normally cover things like how fast your boat might suffer galvanic corrosion, does it?

 

I suspect what is more generally the case is that in most cases, the lamp is wired all the way back to the batteries with two core cable, but that the negative is grounded at both the battery and the lamp end.

 

As head /tunnel lamps are generally only used for short periods, I'm not sure that the brief periods they are used for represents any great threat to the steelwork of the boat.

What I have never fully been able to get my brain around is how harmful is it for the 99.9 something percent of time they are not in use to have a wire connecting the grounded shell of the lamp back to negative at the batteries.  Is it any different from the fact that the left hand side of the hull is electrically joining the front and back of the boat, and the right hand side of the hull is similarly joined?

I would welcome an explanation as to whether a copper cable effectively also joining the same points as are already electrically connected by an infinite number of paths via the shell of the boat presents a significant increased risk of damaging the boat or not.

 

If it was felt it did, the answer to me would seem to be to fit a 2 pole switch for the light, such that the negative wire was broken except when the tunnel light was in use.  I would have thought then that as a tunnel light is only used for very short intervals in the many years the boat exists, that any effects when it was could be ignored for all practical purposes.

But perhaps I've missed something?  If I have can anybody please explain what it is?  Thanks.

[Jen-in-Wellies]

5 minutes ago, alan_fincher said:

 

As head /tunnel lamps are generally only used for short periods, I'm not sure that the brief periods they are used for represents any great threat to the steelwork of the boat.
 

There will always be exceptions. The Standedge and Dudley Tunnel trip boats spring to mind, where they spend a significant part of their working lives with tunnel lamps on!

[alan_fincher]

1 minute ago, Jen-in-Wellies said:

There will always be exceptions. The Standedge and Dudley Tunnel trip boats spring to mind, where they spend a significant part of their working lives with tunnel lamps on!

Hence my use of the word "generally"

I'm guessing if the OP's boat were one of these it would have been fairly obvious!

[ditchcrawler]

4 hours ago, Alan de Enfield said:

Which is on the BSSC check list :

 

3.7.1 Is the electrical system insulated from the hull? 

Check any wiring that can be seen to a suitable device
such as a horn, headlamp, or navigation light for the
presence of a two‐wire insulated cable.

Electrical systems using the hull as a conductor
will not pass this check.

NOTE – an electrical fitment attached to a metal hull or superstructure and having only a single wire
connected indicates the use of the hull as a conductor.

But it only says it has to have 2 wires a live and a return, it doesn't sat the lamp casing must not be earthed. Now how about the car radio with its aerial earthed?

[WotEver]

3 hours ago, ditchcrawler said:

Now how about the car radio with its aerial earthed?

Capacitor in the screen. 

[ditchcrawler]

Just now, WotEver said:

Capacitor in the screen. 

and what percentage do you think have them

 

[David Schweizer]

14 hours ago, ditchcrawler said:

But it only says it has to have 2 wires a live and a return, it doesn't sat the lamp casing must not be earthed. Now how about the car radio with its aerial earthed?

Does the car aeriel always need to be earthed? I only ask because the aerial we had on Helvetia was a taxi radio magnetic base one (similar to illustration below),  which was not earthed, and the radio worked fine. In fact we were also able to use it most of the time for the TV as well.

 

 

 

 

 

Edited January 1, 2019 by David Schweizer

[WotEver]

1 hour ago, David Schweizer said:

Does the car aeriel always need to be earthed? I only ask because the aerial we had on Helvetia was a taxi radio magnetic base one (similar to illustration below),  which was not earthed, and the radio worked fine.

We used the same on WotEver. It worked well. They use their base as a ground plane and capacitively couple to the steel roof. 

12 hours ago, ditchcrawler said:

and what percentage do you think have them

Not nearly as many as should. 

[ditchcrawler]

4 hours ago, WotEver said:

We used the same on WotEver. It worked well. They use their base as a ground plane and capacitively couple to the steel roof. 

Not nearly as many as should. 

I bet its not more that 5% but we will never know. Most people don't have a clue what you are talking about when you mention it

 

[WotEver]

2 minutes ago, ditchcrawler said:

I bet its not more that 5% but we will never know. Most people don't have a clue what you are talking about when you mention it

Nope, and an awful lot of those have the isolator in the negative battery lead too!

[ditchcrawler]

2 hours ago, WotEver said:

Nope, and an awful lot of those have the isolator in the negative battery lead too!

Our share boat did. But thinking about it if the switch was connected directly to the battery negative and nothing else between them then I cant quite see why it wouldn't be quite safe.

[WotEver]

39 minutes ago, ditchcrawler said:

Our share boat did. But thinking about it if the switch was connected directly to the battery negative and nothing else between them then I cant quite see why it wouldn't be quite safe.

Here’s a simple example. Inverter tries to draw 50A. Its chassis is connected to the hull, the radio is connected to the hull via the aerial lead, and is permanently connected to the battery to keep the memories. The radio is fused of course... in the positive lead. 

[ditchcrawler]

2 hours ago, WotEver said:

Here’s a simple example. Inverter tries to draw 50A. Its chassis is connected to the hull, the radio is connected to the hull via the aerial lead, and is permanently connected to the battery to keep the memories. The radio is fused of course... in the positive lead. 

That is why I specified connected directly to the battery negative and nothing else between

[WotEver]

16 minutes ago, ditchcrawler said:

That is why I specified connected directly to the battery negative and nothing else between

But there will always be things that bypass the isolator, the BSS even lists some of them. So your scenario doesn’t exist in the real world. 

[Boater Sam]

8 hours ago, WotEver said:

But there will always be things that bypass the isolator, the BSS even lists some of them. So your scenario doesn’t exist in the real world. 

Tell that to the many guys who have a length of blazing red hot coax coming into their boat!

Seen it happen, its scary.

[WotEver]

1 hour ago, Boater Sam said:

Tell that to the many guys who have a length of blazing red hot coax coming into their boat!

Seen it happen, its scary.

Absolutely my point.

[Chris Williams]

Headlights only used for short periods?  When I was working Jaguar on the Oxford coal run, at least twice I did the 11 mile summit pound at night, headlamp and engine ole lights on.  We were allowed to travel at night then.

Must have surprised a few people to see a loaded boat going past in the dark - ghost boat?

[David Mack]

On 02/01/2019 at 14:15, Chris Williams said:

We were allowed to travel at night then.

Then?? You still are allowed to travel at night (except on the Middle Level).

[David Schweizer]

1 hour ago, David Mack said:

Then?? You still are allowed to travel at night (except on the Middle Level).

 

 Correct.  We regularly ran Moonlight cruises on the K&A when I captained the Trust's trip boat (not many years ago)

 

 

Edited January 7, 2019 by David Schweizer

[Chris Williams]

My mistake, I thought night travel had been banned by the Safety 'Elf.  

[TheBiscuits]

34 minutes ago, Chris Williams said:

My mistake, I thought night travel had been banned by the Safety 'Elf.  

Hire boats on hire are not allowed to travel in the dark for insurance purposes, and I think it may be a licence term too.

 

Private boats are allowed to travel in the dark by the licence, but some insurers refuse to cover the risk, others are quite happy with it.

[Chris Williams]

I assume tunnels are not dark ? .

To go back to the original query, the headlamp that I had on my own boat was an old car headlamp, which had been chrome plated, but I sent it to our platers, who returned it with all the chrome removed, and the brass underneath nicely polished.

As long as the body of the lamp is brass, it can be restored. 

You will, of course, have to keep polishing it.