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Old 11-12-2014, 13:08   #1
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Would this be visible at 2 nm?

Coleman - LED Lanterns | Camp Lanterns | Coleman - Twin High Power LED Lantern

580 lumens appears to be as bright or brighter than the "certified" 2 nm anchor lights. Could run a 12v cord with it and hoist it with the jib halyard.
Or maybe lumens are not created equal? Not to suggest I would use this instead of a "certified" anchor light. I follow all government regulations of course, without question.
I do not see people on camping fora gushing about how fantastic marine anchor lights are for lighting up their campground.
But could be an inexpensive second light, closer to ground and easier for traffic to see.
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Old 11-12-2014, 13:11   #2
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Re: Would this be visible at 2 nm?

best way to test---light 'er up and row or dink away and measure how far you can see the light.
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Old 11-12-2014, 13:35   #3
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Re: Would this be visible at 2 nm?

I think the. Concept of low down anchor light is a good one.

580 lumens is a lot of light. Conventional anchor lights are designed to concentrate their light in a narrow horizontal beam so it is difficult to compare the distance that a camping light, designed for a much broader spread of light would be visible. I would be very surprised if it was less than 2 miles.

One problem is that this sort of brightness, not centred on the horizon, consumes a lot of electricity.

The lamp uses 8D cell batteries with a life of 10 hours on high. A D cell battery has about 15000 mAHrs. That is equivalent to about 12 AHrs at 12v. A lot more energy than a conventional anchor light. If you use alkaline D cell batteries it will be very expensive. If you use rechargeable batteries, or run it direct from 12v then 12AHrs is a lot of energy to replace.

The light might be acceptable at a lower brightness setting, but why not use a proper LED anchor light? This will consume about 2 AHrs. There are some models designed to hung up as you require although sadly the Bebi Owl is no longer available.
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Old 11-12-2014, 14:29   #4
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Re: Would this be visible at 2 nm?

I think the bush lawyers on the forum have pedanticised the whole anchor light rules.

One needs to make a sectional leap from the necessity of an anchor light to one that needs to be seen over 2 nms.

In the days of old farts and their sea dogs with sou wester hats they had a hurricane lamp of kero or oil, unpressurised. Tha was the anchor light.

They run at 50 to 100 lumens.

My guide is that it must be clealy visable to people coming into the area. And 2 nms is way more than necessary.

Your one of 580 lumens will be definilty bright enough... But prehaps it will be SO bright you will never get to sleep. Or so bright that on deck you will be blinded. Or so bright you boat looks like its in a different position than it is, remembering bright lights look closer than dim lights.

So instead of believing the pedants you need to use your seamanship common sense. Other wise we will all be getting all round Lazer lights and making boats crash all over the joint, planes fall out of the sky and Santa and his reindeer miss your whole boat!


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Old 11-12-2014, 14:43   #5
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Re: Would this be visible at 2 nm?

I've got that lantern and it is bright, as in maybe like a 60W 120V light bulb bright.
I bought it primarily to use when grilling after dark, could tell if the steaks were done. It's almost as bright as a gas lantern.

It is as you say a 12V lantern, 8 x 1.5 = 12V, should work well off of the boats battery bank, but there is no plug to do that, you'll have to connect in yourself.

It does have a rheostat and does a very good job at dimming. I got mine from Amazon and I think paid less.
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Old 11-12-2014, 15:44   #6
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Re: Would this be visible at 2 nm?

Mark J and Zee, as practicing cruisers have nailed the essence here: if the light is visible to someone entering that area, it is bright enough. How do you tell? Go and look for yourself! Don't worry about "two miles" so much... take yourself out to the entrance to your anchorage and see if your light(s) can be both seen and differentiated from shore lights. Then approach your boat as if you were a vessel entering without local knowledge. Is your boat or its light(s) visible as you get nearer? This aspect often changes as you get nearer and the relationship to shore lights changes. Finally, as you get really close, can you determine where the boat starts and stops well enough to maneuver around it? In a crowded anchorage, this latter is important, and the lower light can be arranged to illuminate the extremities of the boat with some careful thought... or one can add the dread garden light types at bow and stern for this purpose (but be sure that they stay bright all night, for most do not, even in this less demanding application).

If you are the sort that worries about the letter of the law, be sure that your masthead anchor light meets the regs, for that is the best position for 360 degree visibility. Then run both upper and lower lights all the time. With LEDs the energy cost is not so bad.

Really, this isn't very difficult to do, and do effectively. Good LEDs are pretty cheap, and an enclosure made from a mustard jar or whatever is within everyone's capability.

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Old 11-12-2014, 16:35   #7
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Re: Would this be visible at 2 nm?

My mast is about 80 feet high. and no wires in it right now. So installing a conventional anchor light will not be easy and will be very expensive.Considering the boat is not for cruising but only for day sails, and no plans to be out at night.. unless there is a problem. Its too small of a sailboat to live on for my tastes
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Old 11-12-2014, 17:08   #8
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Re: Would this be visible at 2 nm?

Funny that the Colregs on watch keeping must be obeyed, but the ones on lights, well, they're more like guidelines.

I want to be seen, within reason. In the days of kerosene lamps, there weren't go-fast boats that can cover a mile in the time it takes the driver to fumble for another beer in the cooler.

If you want to know the intensity required of the various lights to achieve visibility at the prescribed distances, you have to refer to Annex I of the Colregs (I know, another pendantic sectional shift), which is full of candelas and horizontal and vertical sectors, over my head.

I did think the below language was interesting:

(b)
(i) All-round lights shall be so located as not to be obscured by masts,
topmasts or structures within angular sectors of more than 6 degrees, except anchor lights prescribed in Rule 30, which need not be placed at an impracticable height above the hull.
(ii) If it is impracticable to comply with paragraph (b)(i) of this section by exhibiting only one all-round light, two all-round lights shall be used suitably positioned or screened so that they appear, as far as practicable, as one light at a distance of one mile.
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Old 11-12-2014, 17:14   #9
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Re: Would this be visible at 2 nm?

I don't know why one would buy a camping light to use as an anchor light when it would be just as easy to buy an actual anchor light, one that's been designed, approved, manufactured and sold as an anchor light.

That's what I did.
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Old 11-12-2014, 18:04   #10
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Re: Would this be visible at 2 nm?

Quote:
Originally Posted by rwidman View Post
I don't know why one would buy a camping light to use as an anchor light when it would be just as easy to buy an actual anchor light, one that's been designed, approved, manufactured and sold as an anchor light.

That's what I did.
Easy. But the cost of a marine part can be ten times the cost of a general use part and only last double the life.

I have lots of non marine parts on my boat... All my LEDs below, for exampe.

Another was Mazda oil filters... They turned out to be exactly to same as the Yanmar filters, exactly the same just branded different.

Agree with Jim re garden solar light. The trick to making them last all night is to replace the batteries. They come with AA 800 mAh. Chamge them for 2,300 mAh and they stay on till dawn
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Old 11-12-2014, 18:16   #11
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Re: Would this be visible at 2 nm?

As I understand the problem with hauling a light up the halyard is it will not be above the mast, which means it will be partly blocked by the mast and therefore not an all around light.

Personally when I'm anchored I'm not so worried about the boat that is 2 NM away. I'm more worried about the one 100 yards or less away that can't see my boat and can't distinguish my anchor light from the stars and other anchor lights. I feel much safer with a light hung lower that illuminates my boat rather than at the top of my mast casting light into the sky above.
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Old 11-12-2014, 18:20   #12
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Re: Would this be visible at 2 nm?

I use a camping lantern with fluorescent tubes. It has 3 settings and uses 8 D cells. I prefer this because I can hoist it up the forestay and it illuminates the whole deck, so I believe my boat is more visible than just a normal anchor light.

I get 3-4 nights from a set of D cells. Kind of expensive if you anchor out every night, I guess. But then it doesn't drain the house battery either. It cost around $30 US.

But the visibility reason was my main consideration.

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Old 11-12-2014, 18:24   #13
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Re: Would this be visible at 2 nm?

Quote:
Originally Posted by nautical62 View Post
As I understand the problem with hauling a light up the halyard is it will not be above the mast, which means it will be partly blocked by the mast and therefore not an all around light.

Personally when I'm anchored I'm not so worried about the boat that is 2 NM away. I'm more worried about the one 100 yards or less away that can't see my boat and can't distinguish my anchor light from the stars and other anchor lights. I feel much safer with a light hung lower that illuminates my boat rather than at the top of my mast casting light into the sky above.
See the Colreg language in post 8, above.
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Old 11-12-2014, 23:05   #14
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Re: Would this be visible at 2 nm?

As for the actual regs..

Lumens don't mean much without knowing the viewing angle, but if you assume it's got 4 crees at 130 lumens each and 120deg viewing angle then the many online converters calc that to be 41 candelas. Irpcs says...
8. Intensity of lights

The minimum luminous intensity of lights shall be calculated by using :
I = 3.43 x 106*x T x D2*x K-D
where I is luminous intensity in candelas under service conditions,
T is threshold factor 2 x 10-7*lux,
D is range of visibility (luminous range) of the light in nautical miles,
K is atmospheric transmissivity.
For prescribed lights the value of K shall be 0.8, corresponding to a meteorological visibility of approximately 13 nautical miles.A selection of figures derived from the formula is given in the following table:

Range of visibility (luminous range) of light in milesLuminous intensity of light in candelas for K=0.8
D I
1 0.9
2 4.3
3 12
4 27
5 52
6 94

So loads probably.

Might rust quickly though. You could make one which would use 0.1A with fairly basic soldering skills.
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Old 12-12-2014, 03:29   #15
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Re: Would this be visible at 2 nm?

Contrary to what some posters have indicated, I think the two mile visibility requirement is important. Not because we need to see an anchor light from two miles away, but because it defines a minimum brightness.

Try entering an anchorage at night with poor visibility due to heavy rain, shore lights behind, with a crew that may not be fully dark adapted because they have been looking at the map of the anchorage. In these sort of circumstances an anchor light needs to be reasonably bright to be easily seen.

I believe the intention of the regulations in setting the two mile brightness limit was not with the expectation that an anchor light needs to be seen at two mile range, rather to insure under adverse conditions the light will be bright enough to be seen at a much closer distance.

Many garden lights are not bright enough to be safe. By all means use them as supplementary lighting, but have one light that meets the two mile brightness requirement.
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