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25-09-2018, 16:13
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#61
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Registered User
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,891
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Re: Running lights - does size matter?
Quote:
Originally Posted by LongRange
That's because flux intensity is not the same thing as luminosity, which is indeed measured in watts.
Flux intensity is a function of the detector's spanned angle. Luminosity is the total power output of the device.
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But "total power output" is irrelevant. Who cares about how much IR and UV a nav light puts out?
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25-09-2018, 16:23
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#62
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Registered User
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,891
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Re: Running lights - does size matter?
Quote:
Originally Posted by Cadence
Since a lumen is the amount of light from one candle. How many candles do I need to light? :-)
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For a "2 mile light", you need 4.3 candela according to COLREGs Annex I.
For 3 mile, you need 12.
As a rule of thumb, you can "sort of" equate candela with the light from a single candle.
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26-09-2018, 07:19
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#63
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Registered User
Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 10,206
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Re: Running lights - does size matter?
Quote:
Originally Posted by StuM
For a "2 mile light", you need 4.3 candela according to COLREGs Annex I.
For 3 mile, you need 12.
As a rule of thumb, you can "sort of" equate candela with the light from a single candle.
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I was asking that in jest. The average boater does not have the equipment to measure light intensity. Maybe an old photographer that used silver might?
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26-09-2018, 07:45
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#64
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Registered User
Join Date: Jul 2011
Location: Vicksburg, Mi
Boat: CT47 Ketch
Posts: 107
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Re: Running lights - does size matter?
1. Get a piece of insanely expensive teak, and mount it on the existing mounting holes, and then get the brightest lights you can find, and use good old fashioned wood screws, properly predrilled holes in the wood, and you will be able to get under and behind the fixture, and replace bulbs or whatever forever. The newer technologies allow boat to be seen farther away, always a good idea. You may eventually have to varnish the teak.
2. I went with a sailing light topmast for open water, and a second set of lights 6-7 foot off the water for harbors. This gives me least electrical use while at sea, and greatest distance view while at sea, and then easiest to see and judge boat size lights while in a crowd.
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27-09-2018, 19:56
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#65
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Registered User
Join Date: Jun 2018
Posts: 132
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Re: Running lights - does size matter?
Quote:
Originally Posted by redbeard1
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Hmmm, very interesting... thanks
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27-09-2018, 20:37
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#66
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,419
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Re: Running lights - does size matter?
Recent observation:
Approaching Fraser Island at night from the NE... I was surprised to see some lights about where the island should have been. Upon scanning with binoculars, I saw the anchor lights from around 8 boats at a distance of 8.6 miles according to the AIS from a couple of them. Only a couple were visible to my naked eyes (but those are kina dim due to advancing cataracts), but they popped right up with the binocs, and by around 6 miles they were visible unaided.
I thought that was pretty outstanding. From the color, they were all LEDs.
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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29-09-2018, 03:57
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#67
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Registered User
Join Date: Feb 2017
Location: Med
Boat: Dufour 455 GL
Posts: 218
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Re: Running lights - does size matter?
Quote:
Originally Posted by StuM
But "total power output" is irrelevant. Who cares about how much IR and UV a nav light puts out?
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When postulating an increasingly powerful source, compared to an original, it is luminosity that is being discussed.
The percentage of that power that is emitted in IR or UV (or gamma) is not going to change appreciably, for a given type of light. Higher luminosity achieves correspondingly higher output in the visible spectrum.
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29-09-2018, 04:18
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#68
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Registered User
Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43 and OPBs
Posts: 12,891
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Re: Running lights - does size matter?
Quote:
Originally Posted by LongRange
When postulating an increasingly powerful source, compared to an original, it is luminosity that is being discussed.
The percentage of that power that is emitted in IR or UV (or gamma) is not going to change appreciably, for a given type of light. Higher luminosity achieves correspondingly higher output in the visible spectrum.
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I refer you to Weim's Displacement Law.
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29-09-2018, 06:26
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#69
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Registered User
Join Date: Feb 2013
Location: Bumping around the Caribbean
Boat: Valiant 40
Posts: 4,625
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Running lights - does size matter?
Quote:
Originally Posted by Nicholson58
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I would be very cautious about putting an LED bulb in a fixture designed for incandescent bulbs, particularly in the masthead tricolor in close proximity to your VHF antenna due to the risk of interference.
I put a Marinebeam led bulb in one of my salon reading lamps and it wreaked havoc with the boat’s stereo. Their replacement bulb for the Aqua Signal May be engineered to prevent interference but I would be suspicious. Determining If it impacts your broadcast range/clarity would be difficult to test.
__________________
"Having a yacht is reason for being more cheerful than most." -Kurt Vonnegut
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29-09-2018, 16:20
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#70
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Moderator
Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 21,419
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Re: Running lights - does size matter?
Quote:
Originally Posted by Suijin
I would be very cautious about putting an LED bulb in a fixture designed for incandescent bulbs, particularly in the masthead tricolor in close proximity to your VHF antenna due to the risk of interference.
I put a Marinebeam led bulb in one of my salon reading lamps and it wreaked havoc with the boat’s stereo. Their replacement bulb for the Aqua Signal May be engineered to prevent interference but I would be suspicious. Determining If it impacts your broadcast range/clarity would be difficult to test.
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The interference associated with LEDs will not involve your transmitted signal at all. Some LEDs have had poorly engineered circuitry that generates RFI, mostly at VHF range frequencies. Nowadays there are manufacturers that have eliminated the problem, and these are quite safe to use at t he masthead. The ones that I use come from Bedazzled, a UK based firm. They have an extensive range of high quality LED "bullbs" and I have been quite happy with them. No connection, BTW... just a user.
Jim
__________________
Jim and Ann s/v Insatiable II, lying Port Cygnet Tasmania once again.
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