Abnormal refraction on the horizon, photographed by Mila Zinkova
On the face of it, this is a rather easy question to answer: collision with an iceberg.
But what caused Titanic to collide with a huge, white iceberg on a completely clear, starlit night?
Her captain was not drunk, her watch officers were keeping a sharp lookout, and she was travelling as fast as was normal in clear weather, even in an ice region: at full speed. Her lookouts were scanning the horizon with their naked eyes, which is the best way to spot an iceberg at night; and Titanic responded well to her helm, turning as swiftly as her highly successful twin sister, the Olympic, whose wartime commander described her as the best handling ship he had ever had the pleasure to command.
And no expense was spared in the building of these ships, which were built on a ‘cost-plus’ basis, meaning the more the ships cost to construct, the more their builder was paid. Both ships were therefore made of the best quality shipbuilding steel available, which in Olympic’s case carried her safely over 600,000 miles, until she was scrapped in 1936 due to the reduced immigrant traffic to New York.
So, the most experienced crew, fully alert; the best and the best-handling ship; the clearest night: what on earth went so terribly wrong?
My search to answer this question led me to fully research the Titanic disaster and introduced me to a lesser-known aspect of the tragedy: the nearby Californian, whose captain ignored Titanic’s rocket distress signals. This became known as ‘The Californian Incident’ and its investigation provided me with the first important clues which would lead me to discover the true cause of the Titanic disaster.
In 1992 this aspect of the tragedy was investigated by the Marine Accident Investigation branch of the British Department of Transport. The two investigators could not agree on whether Californian was only about 5-7 miles away from the Titanic on the night of the disaster, or considerably further away due to abnormal refraction. Abnormal refraction is freak and deceptive visibility which occurs where cold and warm air masses meet, such as where the freezing Labrador Current in which Titanic sank meets the warmer waters of the Gulf Stream, which normally occupied Titanic’s crash site.
Many of Titanic’s passengers noticed the sudden drop in temperature as Titanic entered the freezing waters of the Labrador Current, from the warm waters of the Gulf Stream. This sudden drop in temperature was recorded by Titanic’s most senior surviving officer, Second Officer Charles Lightoller. And after the disaster, when the Mackay Bennett was collecting dead bodies from the water in the area of the Titanic’s sinking, the highly-defined boundary between the warm Gulf Stream and the cold Labrador Current was recorded.
By analysing the water temperature data from 100 ships which passed through the area where Titanic sank, from ten days before the accident to ten days after it, I was able to build a map showing exactly where the freezing water of the Labrador Current meandered through the much warmer waters of the Gulf Stream at Titanic’s crash site.
The air at Titanic’s crash site had been heated by the warm Gulf Stream, which had recently been replaced by the freezing Labrador Current flowing into this area and cooling the air column from the bottom up. This had the effect of trapping cold air below warmer air, an unusual state of the atmosphere known as a thermal inversion. In these conditions the colder, denser air near the sea surface acts as a lens, bending light sharply downwards, around the curvature of the earth, making it impossible to judge distances accurately, and causing unusual optical effects such as Fata Morgana or mirage; and Fata Bromosa or ‘fairy fog’, an apparent fog in the distance where no fog actually exists.
The first evidence that a thermal inversion existed at Titanic’s crash site was that her distress rockets, which actually exploded at a height of 600ft, appeared to rise to only about half the height of her masthead light, when seen from the nearby Californian. This was because the light bending abnormally downwards, around the curvature of the earth, made Titanic appear ‘higher up’ – and therefore nearer – than normal: a phenomenon known as ‘looming’; but her rockets, exploding in the warmer, normally refracting air high above Titanic, appeared at their normal height for their true distance of about 10 miles, and therefore much lower relative to the looming Titanic.
Because Titanic appeared ‘higher up’, but not bigger, she appeared to Californian to be a 400ft ship five miles away, instead of an 800ft ship 10 miles away. Tragically, because Californian knew Titanic to be the only ship within range which had radio, this led Californian to assume that the ship they were looking at did not have radio, because it did not appear to be the Titanic.
Other evidence that a thermal inversion was present at Titanic’s crash site was the smoke from the sinking liner, which hung in layers in the atmosphere, some only a few feet above the water, others much higher up. A heavily stratified atmosphere is a hallmark of thermal inversions because the cold air below is too dense to rise up and mix with the warmer air above, so smoke of various temperatures is trapped in layers in the atmosphere. This is known as a cap, which locks in weather conditions and often causes fog. In 1913 British scientist G.I.Taylor was sent to investigate the area where Titanic sank and recorded many fogs and thermal inversions, as well as photographing the flat-top smoke from his own ship, which similarly hung in layers in the highly stratified atmosphere.
But the air pressure at Titanic’s crash site the night she sank was too high for fog, at 1035mb it squeezed out all the water droplets from the air. This is one of the reasons Titanic was continuing at full speed, because before the Titanic disaster the danger of the ice region was the danger of fog, not ice: ice could be avoided in clear weather but not in fog, so Titanic was anxious to get through the ice region before the pressure changed and the fog came down.
The highly stratified air at Titanic’s crash site also caused extreme scintillation of Titanic’s and Californian’s electric lights, which appeared each to the other as flickering oil lamps, scrambling Titanic’s Morse lamp signals for help, as well as Californian’s Morse lamp signals to Titanic. Second Class Titanic survivor Lawrence Beesley, the science master at Dulwich College, noticed from his lifeboat the very strange atmospheric conditions, and even noted that the stars flashed unusually that night in the keenly stratified air, as though flashing their own, unintelligible Morse lamp signals.
Captain Lord of the Californian should have gone to the aid of the nearby ship that night, but had it not been for abnormal refraction, he would have gone, because he would have realised it was the Titanic in distress, and not just some smaller vessel which apparently did not answer his Morse lamp enquiries.
So, could these conditions of unusual visibility which contributed to the Californian failing to come to Titanic’s aid have caused the disaster in the first place, by causing Titanic to see the iceberg too late?
To answer this question I researched the log books of ships in the area that night. I found that these reported ‘much refraction’ and ‘much refraction on horizon’ and ‘clear horizon with mirage’ and ‘luftspiegelung’, which means mirage in German.
These log book entries were referring to Fata Bromosa, sometimes known as ‘The Fairy Fog’. This was an apparent haze on the horizon which existed on completely clear nights, but was caused by the molecular scattering of light in the great depth of clear air which could be seen through in the miraging conditions, when cold air bends light abnormally downwards, around the curvature of the earth, revealing much more of the earth’s surface than can normally be seen.
As W Kelly noted in 1832 in his essay, “On the temperature, fogs and mirages of the river St. Lawrence”: “There was generally with the mirage an appearance of a fog bank on the horizon . . . . The air within the horizon was at the same time perfectly clear.”
And this unlocked the final mystery of why all the Officers and passengers had described the night Titanic sank as a perfectly clear night, but that several of the Lookouts had mentioned a clear night but with a slight haze around the horizon. The answer is that they were both correct: it was indeed a completely clear night, but there was also a refraction haze on the horizon. This is described rather well by Titanic’s lookouts:
Frederick Fleet: “There was a very slight haze on the horizon. It did not affect us, the haze – we could see just as well.”
Reginald Lee: “A clear, starry night overhead, but at the time of the accident there was a haze extending more or less round the horizon…It was a dark mass that came through that haze”
George Symons: “Pretty clear, Sir, a fine night, rather hazy; if anything a little hazy on the horizon, but nothing to speak of.”
And this testimony of Titanic’s Lookouts is echoed by Second Officer James Bisset of the rescue ship Carpathia, who described what he saw as he was looking towards Titanic’s crash site that night, even giving the correct cause of the hazy horizon: “Though visibility was good, the peculiar atmospheric conditions caused partly by the melting of the large ice field to our northwards in the waters of the Gulf Stream, made the sea and sky seem to blend into one another so that it was difficult to define the horizon.”
In order to avoid accusations of negligent navigation, Titanic’s most senior surviving officer later chose to deny the existence of this peculiar refraction haze, concentrating instead on the unusual and extreme clarity of the night: “We seemed to be able to see a long distance…We could see the stars setting down to the horizon.”
But Titanic Lookout Reginald Lee described the effect this strange haze had on their seeing the iceberg in time to avoid it: “A portion of the berg was above the haze. When I first saw the berg I could not see the lower part of it below the haze. If the whole berg had been covered with haze I would not have seen it so soon”.
Were it not for the Fata Bromosa or ‘fairy fog’ on the horizon, Titanic would have seen the iceberg in time to avoid it; and were it not for the unusually clear night, Titanic would have slowed down in a known ice region.
In short, the Titanic tragedy was caused by a mirage on the horizon, which camouflaged the iceberg in front of it, until it was too late.
Full details on this research can be found in ‘A Very Deceiving Night’, by Tim Maltin