Distance Titanic's lights could be seen

[Mike Spooner]

Whist on the subject of lights. There seems some confusion how far one can see the Titanic lights in miles on a clear night.
Can some one tell me of the following in miles: Morse lamp, mask lights, side lights and passenger lights?

 

[Steven Christian]

According to this thread Dave Gittins states that Capt Lord said his Morse lamp could be seen at 10 miles. So I would think Titanics lamp could be seen that far if not a little more. As for the other lights I'm not sure. But if the whole ship was lit up, passenger lights and all I would think it would be that far also on a clear night. But thats just speculation on my part.

Titanic-Californian Morse lamp communication

From the Californian’s watch that night they observed on the southern horizon a large steamer on a westward heading for a period of time leading up to Titanic’s 11.40 p.m. collision. At this time, the large liner (Titanic) veered to port making her starboard deck lights slowly become...

www.encyclopedia-titanica.org

 

[AlexP]

Whist on the subject of lights. There seems some confusion how far one can see the Titanic lights in miles on a clear night.
Can some one tell me of the following in miles: Morse lamp, mask lights, side lights and passenger lights?

StartLogic

I believe the Titanic's sidelights also had lenses, and yet Mr. Gibson testified he was able to see the sidelight only with the help of the glasses.
I believe it is reasonable to assume that the navigational lights of a much smaller and much older Californian were not nearly as bright as the lights of the Titanic.

 

[Jay Roches]

I’ve seen that article before and wanted to find it again, so thanks for posting the link. Note just how dim the 32-candlepower, 402 lumen masthead light was: about as bright as a 40 W incandescent bulb. And yet, at sea in clear weather, it could be seen at considerable distance.

It may be safe to assume Californian’s lights were less bright, but they still needed to comply with Board of Trade standards. Is there any information about Californian’s lights? They could’ve been 1901-vintage oil lamps that just met the BoT requirements, or the masthead light could’ve been 32-candlepower, just like Titanic. It doesn’t necessarily follow that a bigger ship needs brighter lights. The line-of-sight data, given a lower bridge and mast, would of course differ.

 

[AlexP]

It may be safe to assume Californian’s lights were less bright, but they still needed to comply with Board of Trade standards.

The standards were 5 miles for the masthead lights and 3 miles for the starboard lights I think.

Is there any information about Californian’s lights? They could’ve been 1901-vintage oil lamps that just met the BoT requirements, or the masthead light could’ve been 32-candlepower, just like Titanic. It doesn’t necessarily follow that a bigger ship needs brighter lights. The line-of-sight data, given a lower bridge and mast, would of course differ.

I believe they were electrical, but I do not think they had fancy lenses the Titanic's lights did. I assumed they were less bright because otherwise it is hard to explain why the Californian's lights were first seen from the Titanic some 50 minutes or more after the navigational lights of the Titanic were seen from the Californian.

 

[Samuel Halpern]

Can some one tell me of the following in miles: Morse lamp, mask lights, side lights and passenger lights?

It is not so simple Mike. I wish I had a chance to revise that article (GLTS | Masthead Light) I wrote sometime back on Titanic's masthead light and put it into a wider context. In short, the actual distance depends on essentially two things.
1. the nominal range of the light, which itself depends on the luminous intensity of the light source (after taking into account any magnification due to the dioptric lens that aim at concentrating the light in the vertical plane) for a given meteorological atmospheric condition such as 10 mile visibility for recognizable objects in daytime conditions, and
2. the luminous range, which is the expected range of the same light but under the current meteorological atmospheric condition.

For example, if the nominal range of a certain light is 10 miles under meteorological atmospheric conditions whereby in daytime recognizable objects could be seen as far as 10 miles away, then if that same light is seen at night under hazy meteorological conditions where recognizable objects could only be seen as far as 2 miles during daytime conditions, that light's luminous range would only be 3.5 miles on that night. On the other hand, if the same light is seen at night under very clear to extremely clear meteorological atmospheric conditions whereby recognizable objects could be seen as far as 27 miles away during daytime conditions, that light's nominal range works out to be 18 miles. Under infinite visibility conditions, that same light could be seen out to 45 miles.

Today's rules, masthead lights are designed for a luminous range of 6 miles or greater under a meteorological condition of 13 miles. Sidelights and stern lights are designed for a luminous range of 3 miles or greater under those same conditions.

So to really answer your question, you need to know what the meteorological atmospheric conditions were that night. I could not be too far off if it were varied between what is called very clear and exceptionally clear conditions.

 

[Samuel Halpern]

Back in 1912 the minimum range for masthead lights was 5 miles, for sidelights 2 miles, and for a stern light 1 mile. These are all MINIMUM ranges. If I recall correctly, Morse signaling lights were not as bright as electric sidelights. Their lenses were a lot smaller too.

 

[Mike Spooner]

Thanks for your reply Sam and it show its how not so straight forward as having to allow for atmospheric conditions! There was talk of a haze coming up to no doubt that too would of an impact on the matter as well.
It would appear the Morse code lamp has a greater range than the others at 10 miles. But again subject to atmospheric conditions!
Were the atmospheric conditions for the lighting range ever discussed at the inquires?

 

[Samuel Halpern]

Were the atmospheric conditions for the lighting range ever discussed at the inquires?

Only thing discussed were the rules then in effect, which of course were minimum requirements. It was understood however, that electric lights had greater ranges than the minimums. For the most part, the atmospheric conditions were extremely good that night since stars could be seen setting low down where the horizon would be. Usually, stars tend to extinguish before reaching the horizon because of the greater amount of air mass that their light has to pass through as they get lower and lower down.

 

[Robert T. Paige]

Is the distance you can see these lights also affected by the distance you can see to the horizon ?
Height of the observer, height of the light ?

 

[Mike Spooner]

Hi Sam, not to put you on the spot, do you a have a feeling how far one could of seen any lights in miles, that if it was the Titanic?
I hate to say it the same question for Jim to, or any another seamen as well.

 

[Doug Criner]

The question asked about for a clear night. The maximum visibility depends upon the range, the height of the light above sea level, and the height of the observer. The heights above sea level are important because of the earth's curvature. There are formulas published in nautical sites that cover this. Of course, it will also depend upon the brilliance of the light, the objective size of the binocular lens, and each human's own visual acuity.

What prompts the question?

 

[Samuel Halpern]

Is the distance you can see these lights also affected by the distance you can see to the horizon ?
Height of the observer, height of the light ?

Yes, of course, both. They determine the geographic range. The luminous range does not take that into account. The range that a given light could be seen will the the lesser of the two, the geographic or the luminous range.

Hi Sam, not to put you on the spot, do you a have a feeling how far one could of seen any lights in miles, that if it was the Titanic?

From the bridge of Titanic (height of eye 70 ft) the geographic range to a light at a height of 40 ft is 17 miles. That night, was very clear with stars seen setting right down to the horizon, so the real limitation appears to be geographic range for the most part.
As Doug asked, what prompts the question?

 

[Jim Currie]

Hi Sam, not to put you on the spot, do you a have a feeling how far one could of seen any lights in miles, that if it was the Titanic?
I hate to say it the same question for Jim to, or any another seamen as well.

The only way anyone could be sure the vessel being seen was the Titanic at almost any range, would have been if her side was broad-on or nearly broad-on to the observer.

Observing a normal ship at a distance and approaching is difficult if you are depending only on the visibility of her navigation lights. However, you should all keep in mind that the Olympic class vessels were the biggest, most brightly lit vessel on the ocean at that time. Apprentice Gibson described what an ordinary passenger ship looked like at night: "I have seen nearly all the large passenger boats out at sea, and there was nothing at all about it to resemble a passenger boat. A passenger boat is generally lit up from the water's edge."

If any of you have ever seen a passenger ship at sea at night, you will immediately recognise what Gibson was describing. However, there was an extra bonus withe the Olympic boats...they had no less than five (5) rows of portholes on the side, which extended forward of and below, the masthead light, the red side light and the main deck to sea level.
Many of the forward cabins would have been in darkness before impact with the berg, but many... particularly in mess rooms and crew quarters... would be lit. The lit ones would be visible at about the same time the coloured sidelights were seen. After impact, the whole hull would be lit like a Xmas tree.
To answer your question: A passenger ship like Titanic approaching the stopped Californian on such a night, would have been very obvious at to those on Californian's upper bridge, 11 minutes before she stopped. That is when the lowest row of lit portholes on the starboard bow would have been visible.
Incidentally, Captain Lord said he saw the nearby vessel approaching from a lower deck and saw her green light after 11 pm. He guessed it was about 7 miles away. If that ship had been Titanic, he saw it at 11-22 pm, 8 minutes before she stopped. At that time there would be no possibility of mistaking a ship like Titanic and even a half- blind beggar would have seen her starkly at 4 miles away when she did stop. To suggest otherwise is ridiculously absurd to say the least.

Does the foregoing help to clear the air?

 

[Mike Spooner]

What prompts the question? I would agree on modern cruise ships with many decks lights are a brighter rating than the Titanic was.
However didn't the Titanic start turn off lights by 11.00 for bed time? Therefore make it more difficult to recognise as a passage liner ship!