Subjective testing of nav lights

[Graham_Wright]

Filament light bulbs are expensive to purchase and run (amps). However, they had one design feature that leds cannot exactly mimic. That is the single straight filament which gives near perfect cut off edges.

I have assembled an led array with 42 high intensity leds mounted on a plastic backing that sits at the back of the housing. The array is so arranged to match the cut-off limits.

In order to test its visibility, I have found a line of sight range at around 3 miles. Although not viewed in absolute darkness due to background light from buildings, it compared favourably with the single filament bulb.

The filament lamp draws 2 amps, the leds 330mA. The downside to the arrangement is that maximum output is generated at the centre of the 112.5 arc although the brightness checks were carried out over the whole angle and the variation was not noticeable.

If I can find a longer range, I'll continue the evaluation. (I am not blessed with access to water at the moment but I am "blessed" with living in a hilly area festooned with forests!)

 

[lpdsn]

Have you tried the same test with the usual LED replacement bulbs in nav light fittings? I strongly suspect the concern is overblown as at range the stray light from the side of an LED is much less than intense than the light from the LEDs in that sector, especially if they separate bulbs and fittings. That's what I've observed walking around near the marina but I haven't yet been able to park the boat on a hill three miles away so your results would be interesting.

 

[neil_s]

I've made a similar array for my masthead tricolour. It has 18 x 5630 warm white LEDs arranged in a triangular format and mounted on a bayonet lamp base. It takes 345mA at 12 volts. The spec for the 5630 says that luminous intensity drops to one half at 60 degrees off the boresight. The triangular arrangement thus maintains full intensity over 360 degrees. I confirmed this by setting up my new lamp in a dark room and moving around it with a light meter. So far -so good. I am not sure, however, about the colour purity of the LED lamp. I have just had the mast put up on the boat and I took the opportunity to observe the lamps at a distance of about 100 yards. I switched on the LED mast head tricolour and the deck level filament motoring lights together. White and red sectors compared very favourably, but the LED green looked a bit 'washed out' compared to the 'filament' green. The lens of the tricolour was definitely illuminated green, but the intense LED light source viewed through the lens looked more white to me. The lens of the filament bicolour and the intense filament light source were both green. The LED lamp is up there now, so I will have a look at longer range when I get out on the mooring. Glad to hear from another experimenter!

 

[GrahamM376]

When people have a masthead tri colour, why worry about leds in the lower nav lights? They should only be on when the engine is running.

 

[Daverw]

Does the green look wrong due to the led being whiter than the orange of the original filament, i remember reading somewhere the green is quite specific due to the colour mix

 

[GHA]

I've made a similar array for my masthead tricolour. It has 18 x 5630 warm white LEDs arranged in a triangular format and mounted on a bayonet lamp base. It takes 345mA at 12 volts. The spec for the 5630 says that luminous intensity drops to one half at 60 degrees off the boresight. The triangular arrangement thus maintains full intensity over 360 degrees. I confirmed this by setting up my new lamp in a dark room and moving around it with a light meter. So far -so good. I am not sure, however, about the colour purity of the LED lamp. I have just had the mast put up on the boat and I took the opportunity to observe the lamps at a distance of about 100 yards. I switched on the LED mast head tricolour and the deck level filament motoring lights together. White and red sectors compared very favourably, but the LED green looked a bit 'washed out' compared to the 'filament' green. The lens of the tricolour was definitely illuminated green, but the intense LED light source viewed through the lens looked more white to me. The lens of the filament bicolour and the intense filament light source were both green. The LED lamp is up there now, so I will have a look at longer range when I get out on the mooring. Glad to hear from another experimenter!

The best I've found are cree 503 green LEDs - below is flipping between cool white cree and green cree - doesn't show up very well in the gif but the white ones were a bit blueish and the green ones , well, really green!

Means pretty much building from scratch though and sourcing/building a regulator but more efficient and immune to voltage changes compared to resister current limiting.

 

[neil_s]

That's interesting. I will try and make a new lamp with one triangle side green. The bayonet cap will need to be orientated so that the LED's and lens line up. Problem is the mast is up now, so I can't get at my tricolour!

e-bay sellers seem to be able to supply green 5630 SMD tape strings as a source of a handful of devices.

Resistor limited LED's are my choice. I like listening to the radio and don't like too many switch mode devices around.

 

[GHA]

That's interesting. I will try and make a new lamp with one triangle side green. The bayonet cap will need to be orientated so that the LED's and lens line up. Problem is the mast is up now, so I can't get at my tricolour!

e-bay sellers seem to be able to supply green 5630 SMD tape strings as a source of a handful of devices.

Resistor limited LED's are my choice. I like listening to the radio and don't like too many switch mode devices around.

You can actually make a constant current driver with 2 resisters & 2 components - works great, no switching


https://www.youtube.com/watch?v=Opm-3-hkDEM

 

[neil_s]

Thank you, GHA. Neat device! That's worth a page in the notebook!

 

[PetiteFleur]

I bought one of the MAST tricolour LED lamps and fitted it in a new tricolour lamp. From a distance of about 50 metres it looked fine but you could see the colours straying into the next sector. I epoxied aluminium dividers between the lamp colours to line up with the correct sector and it has improved it. I notice when I was in a local chandlery that HOLT are selling an LED tricolour lamp with similar dividers between the colours. Not tested afloat yet or tested with a traditional vertical filament lamp.

 

[fisherman]

I used auto bulbs instead of long thin 'proper' ones, the lens in the light fitting rectified the display, the cost was 50p against £5. I changed back to the correct bulbs after reading about the MCA investigation of a collision which included checking nav light bulbs. I suspect you will have no problem until there's a problem.

 

[GHA]

I used auto bulbs instead of long thin 'proper' ones, the lens in the light fitting rectified the display, the cost was 50p against £5. I changed back to the correct bulbs after reading about the MCA investigation of a collision which included checking nav light bulbs. I suspect you will have no problem until there's a problem.

What is the allowable overlap anyway? - quick look in the IRPCS didn't find anything.

Suspect a lot of vessels might be a bit on the large side - quite a few seem to stay red/green over a wide area..

 

[fisherman]

What is the allowable overlap anyway? - quick look in the IRPCS didn't find anything.

Suspect a lot of vessels might be a bit on the large side - quite a few seem to stay red/green over a wide area..

It doesn't much matter I think, if you don't have the 'correct' fitting you can argue all you like, if there is an incident, the MCA finds something out of order and the insurance can see a way out you're stuffed. Sensible, allowable, adequate won't come into it.

 

[GHA]

It doesn't much matter I think, if you don't have the 'correct' fitting you can argue all you like, if there is an incident, the MCA finds something out of order and the insurance can see a way out you're stuffed. Sensible, allowable, adequate won't come into it.

Except to IRPCS doesn't actually define a "correct fitting", just what light should come out , how much and where.. very specifically..

Impossible not to have some red/green overlap but with a quick look I couldn't find any mention of how much....

 

[Daydream believer]

but I haven't yet been able to park the boat on a hill three miles away so your results would be interesting.

I have parked on the top of a couple of sand banks that seem like hills surrounded by 3 miles of nice flat walks when the tide goes out. The best of it is that if you do it shortly before dusk you get 11 hours to do your observations.
I can point them out, now that i have found them, if that would help :ambivalence:

 

[zoidberg]

I have parked on the top of a couple of sand banks that seem like hills surrounded by 3 miles of nice flat walks when the tide goes out. The best of it is that if you do it shortly before dusk you get 11 hours to do your observations.
I can point them out, now that i have found them, if that would help :ambivalence:

Would they be called 'Maplins' by any mischance? And can you get replacement 'luminaires' there.....?

 

[fisherman]

http://www.otenmaritime.com/interna...s/application-definition-visibility-of-lights

Theoretically no overlap, but of course much depends on the beam of the vessel.

 

[GHA]

http://www.otenmaritime.com/interna...s/application-definition-visibility-of-lights

Theoretically no overlap, but of course much depends on the beam of the vessel.

Apparently there is allowable - had to be in there somewhere

Annex 1

9. Horizontal sectors


(a)


(i) In the forward direction, sidelights as fitted on the vessel shall show the minimum required intensities. The intensities shall decrease to reach practical cut-off between 1 degree and 3 degrees outside the prescribed sectors.

So worst allowable 3 deg either side you could see both for about 0.1Nm when 1Nm away.

 

[prv]

When people have a masthead tri colour, why worry about leds in the lower nav lights? They should only be on when the engine is running.

Why should they?

I use deck-level navigation lights most of the time, whether under power or sail. They're more visible to other small craft at the sort of range that it matters, and in inshore waters I'll be staying out of the way of the big stuff.

Really your question is backwards - now that we can have LEDs in the lower nav lights, why bother with a tricolour? It was only invented as a 1970s concession for small yachts that couldn't run multiple 25w filament bulbs all night, and it requires a long cable run to an awkward location.

Pete

 

[prv]

So worst allowable 3 deg either side you could see both for about 0.1Nm when 1Nm away.

...assuming the yacht is perched on top of your test hill, and not swinging from side to side at sea.

In reality, if you're located 1 mile dead ahead of a yacht under way, you're going to be seeing alternating green and red (and possibly brief flashes of white due to overlap?) as she yaws in the waves.

Pete