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Boat horn wiring.


PaulG

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Bought new horn, drilled and tapped holes in roof, applied plenty of siilicone sealant, mounted horn. Stood back and admired the nice neat job.

Pressed horn button to be rewarded with a brief and barely audible "ponk" noise.

Many swearwords later, new horn is removed from roof, and 12v power applied direct from socket results in an ear-splitting blast.

Seems to be voltage drop from the parsimonious builder's wiring. Couldn't actually measure it as arms and meter leads not long enough, but all connectors new, bright and shiny so that is the conclusion that I have come to.

Can't get at the wiring as it's all behind the fitout.

I'm thinking of rewiring it to use both conductors as positives, and then use the hull as the return negative.

Seems to me that the total operation time of the horn is probably 30 seconds a year at the most, so it seems unlikely to cause too many problems.

Anyone else done this?

Any BSS issues?

Anyone care to comment?

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Yes, BSS fail. The other thing you could consider is trying to adjust the horn to cope with the lower voltage. Some horns have a central screw adjustment that changes the contact gap, and tweaking that might allow the horn to work. Also check it with the engine running - the system voltage will be higher with the engine running and might be enough to overcome the voltage drop. I suggest it doesn't matter too much if the horn doesn't work when the engine is shut down - transits of Harecastle tunnel perhaps excepted.

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5 minutes ago, PaulG said:

Hmmm.

Thanks Martin. Depends on whether my mods can be seen, really...

Not sure about that, do you really want to own/operate a boat that does not comply with the safety regulations?  It may well also invalidate your insurance if you ever make a claim. 

Edited by David Schweizer
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3 minutes ago, David Schweizer said:

Not sure about that, do you really want to own/operate a boat that does not comply with the safety regulations?  It may well also invalidate your insurance if you ever make a claim. 

A boat with a horn that doesn't work seems to me to be a bigger risk than a missing conductor...
Anyway, all things considered, I'll probably leave the wiring alone, put the horn on our workshop power supply and see if I can adjust it so that it operates at a lower voltage as Nick suggested.

There was plenty of grunt there when I tested it on the boat the first time as I was on the landline with a Sterling charge running.

Thanks for your input folks!

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As far as I am aware the adjusting screw is used to tension the horn diaphragm return spring or alter the contact gap. Maybe  altering the gap would allow it to work with the reduced magnetic field trying to separate the contact but from experience I would suggest it is only likely to be a short term fix.

 

 

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If you have a bow thruster with batteries at the front of the boat, you could fit a relay, so that the original wiring and push button controls the relay and the closed relay contacts may the circuit for the horn from the BT batteries.

Alternatively, do what I have done and purchase an air horn.

http://www.outdoorgb.com/p/Ecoblast_Signal _Horn_Pump/?utm_source=froogle&utm_medium=directory&utm_content=GBR&currency=GBP&country=GBR&SelectedBundle=151054&gclid=CjwKEAjw4IjKBRDr6p752cCUm3kSJAC-eqRt58gWiTorJsCs29P8Uyod7OEgLQ2sjR3ZFQu3pTC4hhoCFz_w_wcB

Edited by cuthound
Spillung
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What size is the tunnel light feed? If it's larger than the horn feed then you could swap them over at both ends and use an LED tunnel lamp. 

Or parallel the tunnel lamp and horn feeds for powering the horn and use a battery operated tunnel lamp...

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3 hours ago, PaulG said:

A boat with a horn that doesn't work seems to me to be a bigger risk than a missing conductor...
Anyway, all things considered, I'll probably leave the wiring alone, put the horn on our workshop power supply and see if I can adjust it so that it operates at a lower voltage as Nick suggested.

There was plenty of grunt there when I tested it on the boat the first time as I was on the landline with a Sterling charge running.

Thanks for your input folks!

It doesn't really matter what your, or any one else, thinks on the matter. If the BSS regulations state that negative hull return is not permitted, your boat will fail if the exanminer discovers that the boat does not comply. It could well alaso cause the examiner to wonder what othe "short cuts" on safety have been taken.

Running two wires is not that difficult, even if you have to remove some lining to fit it. I ran numerous new cable runs on Helvetia and must have removed about 60% of the lining at various times to do it.

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1 hour ago, David Schweizer said:

It doesn't really matter what your, or any one else, thinks on the matter. If the BSS regulations state that negative hull return is not permitted, your boat will fail if the exanminer discovers that the boat does not comply. It could well alaso cause the examiner to wonder what othe "short cuts" on safety have been taken.

Running two wires is not that difficult, even if you have to remove some lining to fit it. I ran numerous new cable runs on Helvetia and must have removed about 60% of the lining at various times to do it.

Exactly how high is that horse you're on David?

:P

I already indicated that I was not going down the "single conductor" route.
Or maybe you just misunderstood what I was saying...

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25 minutes ago, PaulG said:

Exactly how high is that horse you're on David?

:P

I already indicated that I was not going down the "single conductor" route.
Or maybe you just misunderstood what I was saying...

I am not sure that I misunserstood anything you were saying. The word "probably" suggested the alternative of not doing it, and your opening statement seemed to suggest a reluctance to accept the legal requirements, when measured against your opinion.

If you are now saing that you definityely will not use the hull as a negative return that is good.

 

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1 hour ago, Chewbacka said:

If you don't want to run a new heavy cable from the battery at the back to the horn at the front, you could put the horn at the back to be near the batteries.

Radical idea: Fit a small Yuasa sealed lead acid battery somewhere up near the pointy end, permanently charged by the horn feed, which is now left permanently live. Operate the horn from that batt using an RF relay: https://m.miniinthebox.com/12v-2-channel-wireless-remote-control-relay-module-with-remote-controller-dc28v-ac250v_p1636343.html?currency=GBP&litb_from=paid_adwords_shopping&utm_source=google_shopping&utm_medium=cpc&adword_mt=&adword_ct=153421710168&adword_kw=&adword_pos=1o1&adword_pl=&adword_net=g&adword_tar=&adw_src_id=9772115911_686959893_34986925323_aud-146622001962:pla-290562549814&gclid=CjwKEAjw4IjKBRDr6p752cCUm3kSJAC-eqRttR-6mGtcJoz-OA537AbRYcfdWVeb9t_K__ILAlp3ChoCADbw_wcB

Hey, I never said it was a GOOD idea...

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21 hours ago, WotEver said:

But it is a very good idea for turning on a deck light for when I'm returning from the pub in the dark........

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On 15 June 2017 at 11:00, Martin Megson said:

I believe it will fail BSS:

 

59425a847d4c1_ScreenShot2017-06-15at10_59_00.png.ddb90ec2fe27b2344e1085e218b7c745.png

It's an Advisory check, not a Required one, so you would still pass BSS, albeit with an advice note. Still doesn't make it a good idea though. You don't necessarily need to replace the wiring you have though, you could run a supplementary feed if you can find a route to do so unobtrusively, it doesn't have to follow the same route?

  • Greenie 1
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On 2017-6-15 at 14:03, cuthound said:

If you have a bow thruster with batteries at the front of the boat, you could fit a relay, so that the original wiring and push button controls the relay and the closed relay contacts may the circuit for the horn from the BT batteries.

Yes, that's what I did. The horn is powered by the BT batteries and the original switch operates the horn via a relay. 

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  • 2 weeks later...

You could still go down the route of using your existing wiring as a 'double conductor' if you have a convenient path to a -ve cable near the installation, such as a main circuit or the water pump. Avoid using the tunnel light -ve, as if you have a need to use both at the same time, you may find that you lose both appliances. Guess how I know :blush:

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On 15/06/2017 at 11:11, David Schweizer said:

Not sure about that, do you really want to own/operate a boat that does not comply with the safety regulations?  It may well also invalidate your insurance if you ever make a claim. 

 

I'd be interested to find out what safety risk is presented by using the hull as a negative return for a horn. None, in my opinion. Another good example of BSS bollux in my opinion,

And regarding your second point, about insurance, f I'm wrong about the above, I very much doubt there will be a significant insurance claim resulting from using the hull as a negative return. Happy to be shown wrong though.

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I don't think its a safety risk but I am pretty well convinced it increases the chance of hull corrosion if any electrons find their path restricted by (say) a weld so bypass it via the water.  However I doubt the about of time a horn would be in use would make a measurable difference.

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On 27/06/2017 at 13:01, Tony Brooks said:

I don't think its a safety risk but I am pretty well convinced it increases the chance of hull corrosion if any electrons find their path restricted by (say) a weld so bypass it via the water.  However I doubt the about of time a horn would be in use would make a measurable difference.

 

Yes exactly. 

The BSS has no business straying into enforcing good design practice.

If the owner wants to corrode his hull unnecessarily quickly to save a few quid on wires, it is not for the BSS to prevent him from doing so.

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