2nm vs 3nm Navigation Lights

[SV Confianza]

Hi All!

I'm finally getting around to replacing our Nav lights to LEDs. I had already replaced the tricolor, which is mostly what we're using when we're offshore sailing. But I cracked the port light, and I'm moving the stern light anyway to the solar arch, so why not just get the replacement done...

Question is....is it worth it to go with 3nm rate lights vs 2nm rated lights? We do a decent amount of off shore sailing, and 2nm seems very short.

The rating for a 2nm boat is something like boats under 65ft in length, and we are a 44ft catamaran, so that should be sufficient. But, it just seems wrong for offshore sailing.

After reading a number of posts on this forum about favorite brands of nav lights, I had settled on MarineBeam: https://store.marinebeam.com/uscg-2nm-led-stern-light/ from recommendations on the forum, actual certifications for RFI, and the fact that they attempt to use a diffuser shield.

I really hate LED lights that don't diffuse the light at all, and you can't tell if the other boat is 50 ft in front or 2 miles in front of you at night.

But these are only 2nm rate.

Obviously we have modern AIS, Radar, and all of that stuff for safety, but I still think good navigation lights are important.

Any opinions?

[rslifkin]

The 2nm visibility lights are pretty bright (unlike the 1nm visibility stuff some small boats have, which I think are useless). I can't say I've ever felt the 2nm side/stern lights and 3nm steaming light on my boat to be inadequate, but brighter doesn't hurt. The next step up would be 3nm side/stern lights and you can go to a 5nm steaming light.

For offshore use, I'd think a good side/stern light combo and then the masthead red over green may be better visibility-wise than just a tricolor.

[jordanbigel]

Originally Posted by SV Confianza

Question is....is it worth it to go with 3nm rate lights vs 2nm rated lights? We do a decent amount of off shore sailing, and 2nm seems very short.

...
...
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Any opinions?

Opinion: Yes.

Why: A ship moving at 20k will cover 1nm in just 3 minutes.

With a 2nm range light, that means the ship will see you 6 minutes before it hits you.

Obviously 9 minutes is better than 3 minutes because it gives the ship more time to recognize a potential collision and make a course adjustment.

[Orion Jim]

I’d stick with the 2nm rated LED’s of your choice. I have Hella NaviLED PRO’s which are great. AIS is what is real important…buy the best you can afford and have your antenna and connections tested to be certain you are sending and receiving at an optimal level.

[SV Confianza]

Originally Posted by rslifkin

The 2nm visibility lights are pretty bright (unlike the 1nm visibility stuff some small boats have, which I think are useless). I can't say I've ever felt the 2nm side/stern lights and 3nm steaming light on my boat to be inadequate, but brighter doesn't hurt. The next step up would be 3nm side/stern lights and you can go to a 5nm steaming light.

For offshore use, I'd think a good side/stern light combo and then the masthead red over green may be better visibility-wise than just a tricolor.

Yeah I don’t think my tricolor is terribly bright even though it’s brand new. But I default to it with offshore waves or downwind sails that can block the Nav lights.

[SV Confianza]

Originally Posted by jordanbigel

Opinion: Yes.

Why: A ship moving at 20k will cover 1nm in just 3 minutes.

With a 2nm range light, that means the ship will see you 6 minutes before it hits you.

Obviously 9 minutes is better than 3 minutes because it gives the ship more time to recognize a potential collision and make a course adjustment.

Yeah while I think the 2nm lights can probably be seen much farther than 2nm in most conditions, I’m with you on the math.

[SV Confianza]

Originally Posted by Orion Jim

I’d stick with the 2nm rated LED’s of your choice. I have Hella NaviLED PRO’s which are great. AIS is what is real important…buy the best you can afford and have your antenna and connections tested to be certain you are sending and receiving at an optimal level.

Yeah we have all new electronics (relatively, 2 years old) so the AIS is covered. I just don’t like relying on it as the sole answer.

[Madehn]

I believe 2 nm lights to be sufficient. Especially if they are at mast top. I have occasionally flashed my spreader lights on my sail to get more notice

[noelex 77]

Given the low power consumption of LED emitters, I think the brighter the better.

However, some manufacturers (for example Hella) are releasing 3nm rated lights that achieve this greater range with a more concentrated beam. This means they do not achieve adequate dispersion to be approved for sailboat use (sailboats heel).

Make sure if you are picking a 3nm version that it is approved for your type of boat.

[El Pinguino]

Some people seem to think that '3 mile' or '2 mile' involves some sort of magic - you can see the light at 1.99 miles but not at 2.01 miles f'rinstance.
It actually involves quite a complex calculation involving 'a meteorological visibility of approximately 13 nautical miles.'
And also - the only Hella 3 mile LED I can find is a 'masthead' or 'steaming' light. This one - https://www.hellamarine.com/en/produ...tion-lamp.html
Ditto the MarineBeam lights.

From the annex to 'the rules'
'8. Intensity of lights
(a) The minimum luminous intensity of lights shall be calculated by using the formula:

where: I is luminous intensity in candelas under service conditions,
T is threshold factor 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.
(b) A selection of figures derived from the formula is given in the following table:
Range of visibility (luminous range) of light
in nautical miles
D
Luminous intensity of light in candelas
for K = 0.8
I
1
0.9
2
4.3
3
12.0
4
27.0
5
52.0
6
94.0
Note The maximum luminous intensity of navigation lights should be limited to avoid undue glare. This shall not be achieved by a variable control of the luminous intensity.'


'Rule 22
Visibility of lights
The lights prescribed in these Rules shall have an intensity as specified in Section 8 of Annex I to these Regulations so as to be visible at the following minimum ranges:
(a) In vessels of 50 metres or more in length:
‑ a masthead light, 6 miles;
‑ a sidelight, 3 miles;
‑ a sternlight, 3 miles;
‑ a towing light, 3 miles;
‑ a white, red, green or yellow all‑round light, 3 miles.
(b) In vessels of 12 metres or more in length but less than 50 metres in length:
‑ a masthead light, 5 miles; except that where the length of the vessel is less than 20 metres, 3 miles;
‑ a sidelight, 2 miles;
‑ a sternlight, 2 miles;
‑ a towing light, 2 miles;
‑ a white, red, green or yellow all‑round light, 2 miles.
(c) In vessels of less than 12 metres in length:
‑ a masthead light, 2 miles;
‑ a sidelight, 1 mile;
‑ a sternlight, 2 miles;
- a towing light, 2 miles;
‑ a white, red, green or yellow all‑round light, 2 miles.
(d) In inconspicuous, partly submerged vessels or objects being towed:
‑ a white all‑round light, 3 miles.'

[noelex 77]

Originally Posted by El Pinguino

And also - the only Hella 3 mile LED I can find is a 'masthead' or 'steaming' light. This one - https://www.hellamarine.com/en/produ...tion-lamp.html

This is the link to the Hella 3nm port and starboard navigation lights:

https://www.hellamarine.com/en/produ...tion-lamp.html

The extra range between 2nm and 3nm can be achieved by making the light brighter (which is good), or by restricting the spread of the light beam, which is is bad for a sailboat. If buying navigation lights make sure how the extra range is achieved and whether this is appropriate for your vessel.

Hella have achieved the extra range by concentrating the beam. Consequently, these lights are not approved for a sailboat.

[El Pinguino]

Its a sad day when I don't learn something new.
Seems the 'propellor' mark means power boats only - in Europe.
Page 8, 4.2.2
https://unece.org/fileadmin/DAM/tran...%20No7%20E.pdf

Bit of a 'mix and match' on this Hella page.
https://www.hellamarine.com/en/produ...-professional/

[SV Confianza]

Thanks for all the input guys. I think I’ll go with the 2nm MarineBeam for now and see how it works out. I definitely don’t want to get a 3nm with concentrated beam. Even though it’s a cat and doesn’t really heel, I hate the LEDs without diffusion that make it so you can’t tell how close something is to you.

[davil]

Originally Posted by SV Confianza

Thanks for all the input guys. I think I’ll go with the 2nm MarineBeam for now and see how it works out. I definitely don’t want to get a 3nm with concentrated beam. Even though it’s a cat and doesn’t really heel, I hate the LEDs without diffusion that make it so you can’t tell how close something is to you.

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Excellent choice from reading the specs.

There is a thread about collision and dismasting, didn't want to post there as not to complicate that thread BUT visibility was an issue as both vessels didn't see each other.

Last season cruising, I lost my
bow installed combination light at midnight!!!

Next day I opened the light case and was horrified to see the bulb come apart from the contacts, everything corroded falling apart.(AquaSignal)

Received my new Hella replacement, happier as doubles the range from 1 NM to 2 NM.

Also, more water protection.

On reading this thread became aware of the brand MarineBeam.
Wish had known before.

After my experience with water intrusion and damage paying attention to it and found on the description

Hella rated as IP55
MarineBeam IP67

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Is IP55 fully waterproof?
This rating has limited protection from dust and water, making it an option for indoor and outdoor uses. However, products with an IP55 rating are not waterproof.Jul 7, 2023

What is IP67 waterproof mean?
That said, if you want a device that can be submerged in water (when you swim or when you're at the beach, for example) you'll want a product with an IP67 or IP68 rating. “With IP67, devices are considered water-resistant up to a depth of about 3 feet for up to 30 minutes,” says Kelso.Aug 14, 2023

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Oh well

will open the case of the Hella once a year before starting the season,

[Bowdrie]

Many years ago I went with the "Peters & Bey" series 410 lights.
At that time their prices, while high, were at least somewhat reasonable.
Today they seem to be ridiculous/over the top gouging.
But they are a decent light.
My beef with most all lights is that they seem to use terminals/screws that one might find in a watch.
https://store.sandiegomarine.com/pro...410-15477.html