Californian and Titanic and the use of Running Lights

[Jim Currie]

For those who are interested:

The vertical separation between these lights would be not less than 15 feet and the horizontal distance at least thee times that. The forward one would be the lower of the two.
Thus at a distance at night; an observer would have a good idea of the direction in which the ship showing the lights was heading .
In the case of Californian; it would seem that the vertical separation between her two mast lights was close to 25 feet.

Titanic's masts were about 600 feet apart. This distance was too great to make the fitting of a second white light on the main mast practical. If the above formula was to be used, the vertical separation of such lights would need to have been in the region of 200 feet.
Since the one on the foremast was above the crows nest, the second on the main mast - a second light might have to have been mounted on the first funnel which would be impractical.

The separation formula is not strictly arbitrary.
For two masthead lights to perform in a satisfactory manner - i.e. show direction of travel - the separation must be obvious to an observer from another vessel. Such lights could not be fitted on Titanic's mast and obey the formula therefore they would have appeared to be almost in a straight line as seen by a distant observer. Perhaps the following sketch illustrates what I mean:

You have to imagine that there would have been complete darkness and the ship would be invisible - just did it this way to show position of the lights on the ship.

I have made the lights bigger for clarity.
In Sketch A, I show where a second light would need to be to obey the formula.

In Sketch B, I show a light mounted on the mainmast. Observe how they seem almost to be in a straight line.

By the way - not to scale!

 

[Samuel Halpern]

A second masthead light was later fitted onto Olympic and to Britannic, Titanic's sister ships. For those that have a copy of Simon Mill's "Hostage to Fortune," you can see this in the H&W rigging plans at the back of the book. The 2nd masthead light was fitted just a few feet under where the wireless antenna connected to the mast. There was also a ladder running up the mast on the starboard side to enable the light to be maintained. The position of the masthead light on the foremast was the same as on the original Olympic plan and on Titanic.

 

[Samuel Halpern]

Also for those interested, the rules in effect at the time of Titanic regarding the carrying of navigation lights can be read in my article, Titanic's Masthead Light.

 

[Jim Currie]

Sam,

Where was this second light fitted relative to the first one? I don't have access to the books you refer to.

 

[Samuel Halpern]

This shows where these masthead lights were located.

 

[Jim Currie]

Thanks Sam!

Heaven knows who thought that one up. It merely follows that part of Article 2, subsection (e) which states: 'the vertical distance shall be less than the horizontal distance'. It does not consider WHY the horizontal distance should be so. It looks to me like that was a token gesture. It would not have met with later regulations, that's for sure. I would have thought it would have been more effective to hoist a second mast head light from a block on the jumper stay between the first and second funnels. It could have been mounted in a special screened box.
Consider how such a ship might appear to an observer from any more than a few miles away:

In the following, I have assumed Titanic is about five miles away at A.. no side lights visible. Then she is represented as getting closer and turning either right or left..the side lights become visible but so do the accommodation lights.

The most important time for the observer in the case illustrated is time of first sighting - at 'A'. Particularly if the ship he's observing is moving at 22.5 knots and both ships are heading straight for each other! He doesn't have much time to make up his mind what he needs to do - possibly less than 8 minutes. He needs to know quickly how that other ship is heading to avoid the possibility of collision. As you know there are two ways to do this -
To observe the other ship's lights or take a bearing of the other ship to see if the bearing changes appreciably.

Given the worst scenario; taking a bearing at such a close quarter encounter is useless.

The range of visibility of the coloured lights is 3 miles but the white one(s) is 5 miles.

At 3 miles there is less than 5 minutes to collision in this scenario. A single white masthead light would tell the observer nothing - nor would two masthead lights almost at the same horizontal level. However, vertical separation with the lower one toward the bow would clearly indicate direction of travel without seeing the sidelights. This following is what an approaching Californian might have looked like to an observer.

I show her seen at first right ahead and showing masthead lights only. Then how she would have looked passing to the observer's right(green light) or left (red light). This also illustrates the effectiveness of vertical separation when trying to determine how the other ship is heading when at extreme range and without the help of sidelights:

I know you know all this Sam but others might like a a rough guide to what we're discussing.

 

[Bill Wormstedt]

George Behe also has several diagrams/pictures of what the Titanic would have looked like that night. "She Shut Her Lights Out, My Lord."

 

[Jim Currie]

Hi Bill!

Nice pictures but there would have been all that light flooding forward of the bridge. It would have reflected on structures such as the fore mast, crow's nest, cranes the forecastle; ruining the night vision of the OOWs. It would have been fine when at anchor but not underway.

Also, in one of the pics, the masthead light is seen without the starboard side-light - not possible unless there was a problem with it or the green light. They both show over the same arc of visibility.

The ideal situation was for superstructure and accommodation lights to be aft of the coloured lights and no lights other than navigation lights to be seen from vessels right ahead.

 

[Jim Currie]

Sorry Bill - wrong use of words makes misunderstandings!

I should have finished my last with 'no lights other than navigation lights to be seen BY (not 'from') vessels right ahead [of Titanic].

Jim.