Recent findings
After the discovery of the wreck, some controversial questions could be answered. Thus, due to the position of the bow and stern, it is considered certain that the Titanic broke apart already near the water surface. The breakup of a ship of this size can also occur in far less spectacular situations, as in the case of the America.
The leaks of the Titanic
One of the biggest mysteries surrounding the ship is the exact dimensions and nature of the damage caused by the iceberg. As early as 1912, Edward Wilding, who was responsible for watertight subdivision and flooding calculations during the construction of the Titanic, had determined the total leak size to be approximately 1.2 square meters. At a water depth of seven metres (3.5 metres above the keel plate), even this small area is sufficient for an inflow of 400 tonnes per minute, which was calculated for the initial phase of the sinking process on the basis of the flooding speed. Assuming a continuous leak across the forward six compartments, as in many accounts of the disaster, the average gap width would be less than two centimetres. Wilding rightly considered this highly unlikely, as did the theory, also circulated after the accident, that an iceberg spur had cut the leak into the ship's outer skin. This is physically impossible due to the low hardness of ice compared to steel.
Since the bow dug deep into the bottom when it hit the sea floor, most of the iceberg damage is not directly visible. This problem was solved during an expedition in 1996. This involved the use of a special sonar that can provide images even through the upper layers of the bottom. Six different leaks were found, the formation of which is described by the experts involved by the "re-impact theory". This theory is based on the assumption that the ship hit the iceberg several times, in each case losing speed and pushing off, but then bouncing back onto the iceberg due to forces caused by the evasive manoeuvre and the Bernoulli suction as well as the widening hull of the ship. This theory is not only consistent with the measured leaks, but also with various statements by survivors who were in the lower bow area during the collision and had recorded several strong impacts.
The first of the leaks was in the forepeak just below the waterline. The next two were at the same height shortly after each other in cargo hold 1 and were only 1.2 and 1.5 metres long respectively. The impacts that occurred were strong enough to knock off part of the iceberg, so that the next leak, 4.6 metres long, was caused by an impact at a lower point on the iceberg. This again sheared off part of the iceberg, leaving the last two leaks even deeper below the waterline. The penultimate one was about ten metres long and extended from cargo hold 2 well into cargo hold 3. The impact was so severe that, according to survivors, the watertight service corridor for the stokers, located 0.5 metres behind the hull, was also damaged and quickly flooded. The last leak was the longest at 13.7 metres. There is still a large bulge in the bulkhead between boiler rooms 5 and 6, probably caused by compression effects due to the ship's rotation. After evaluation of the damage found during this sonar scan, as well as computer-aided flooding calculations, the following distribution of opening areas has resulted:
| Damage |
| Department number | Department name | Leakage area
square meters |
| 1 | Forepeak | 0,06 |
| 2 | Cargo hold 1 | 0,14 |
| 3 | Cargo hold 2 | 0,29 |
| 4 | Cargo hold 3 | 0,31 |
| 5 | Boiler room 6 | 0,26 |
| 6 | Boiler room 5 | 0,12 |
| 1–6 | collectively | 1,18 |
Materials
Investigations into the materials used in the construction of the ship were also central to determining the possible causes of the accident. Investigations into the materials of steel recovered from the Titanic revealed very low toughness at the temperature prevailing at the time of the collision. This brittleness of the material could have caused a greater extent of damage than would have occurred with today's materials.
However, the theory is doubted by various sides. The changes in Titanic's steel may also have resulted from the special conditions in the deep sea. Pictures of the construction of the Titanic and the Olympic show steel plates that were used for both the one and the other ship. The Olympic was in service for 24 years before being scrapped, and had survived several years of war service and various collisions. Moreover, about the same steel was used in shipbuilding all over the world at that time, as for example in the Russian icebreaker Krassin, built in Newcastle in 1916, which is still unrestrictedly seaworthy. The Queen Mary, completed in 1936, was also built from the same type of steel, with steel plates identical in origin and thickness to those used on the Titanic. It was only after the Second World War that research was carried out into better materials, making modern ships much lighter than earlier ones while retaining the same size and stability.
Another possible weak point of the Titanic's outer skin were the rivet joints between the steel plates. Not only the stability of the rivet itself seems to be problematic, but also the area around the cold-punched rivet holes in the steel plates, where micro-cracks formed as a result of the punching process. As early as after the collision of the Olympic with the Hawke in September 1911, Edward Wilding, after assessing the Olympic damage, had already judged the method of joining the plates to be in need of improvement and had initiated a discussion about changes for future ships. The rivet holes on the Queen Mary, built 25 years later, were drilled despite the much higher cost.
The relative weakness of Titanic's riveted joints is supported by the leaks found, most of which are along the riveted joints between the steel plates. However, according to the experts, even modern welded steel plates would probably not have withstood the forces acting during the iceberg collision.
The bunker fire
Some other theories on the cause of the accident deal with the effects of the fire in a coal bunker on the starboard side between boiler rooms five and six. One of these comes from 2004 by Ohio State University engineer Robert Essenhigh. He argues that, according to Southampton Harbor Fire Department records, a smoldering fire in the bunker in question caused the captain to sail faster than would have been appropriate for the situation, despite the danger of icebergs. The fire may have been fought in the usual method of the time, by shovelling coal from the affected bunker into the boilers faster than usual to get at the burning coal. The ship had therefore been travelling at excessive speed in the iceberg area and it had therefore been impossible to slow down in time. According to statements by surviving stokers, however, the bunker in question was already empty on Saturday and the fire extinguished. Furthermore, the witnesses had subsequently noticed damage to the adjacent watertight bulkhead, the extent of which and possible influence on the function of the bulkhead during the night of the accident could not, however, be assessed precisely.
Unproven accusation of insurance fraud
In 1996, the authors Robin Gardiner and Dan van der Vat published a conspiracy theory in the book The Titanic Conspiracy, according to which the sinking of the Titanic was a calculated insurance fraud. According to the theory, it was not the Titanic that sank in the North Atlantic, but her sister ship, the Olympic. The insurance fraud, according to the authors, was based on an accident involving the Olympic that occurred during her fifth North Atlantic voyage. At the time, she collided with the British warship Hawke and suffered severe damage to the starboard side of her hull. While she was being repaired in the shipyard, she lay alongside the Titanic, which was under construction. During this period, according to theory, the nameplates of the ships were switched to allow the damaged Olympic to sink in the Atlantic and the real Titanic to continue sailing as the Olympic, in order to save on follow-up repairs and to preserve the Titanic's insurance money. However, it is said that the plan was to have the passengers of the "false" Titanic rescued by another ship of the White Star Line. One indication of this is that J. P. Morgan, the owner of the Titanic, did not make his booked crossing due to illness.
However, this theory is contradicted by some components that have been examined since the discovery of the wreck by Robert Ballard in 1985. On all recovered objects the construction number 401 of the Titanic and not the 400 of the Olympic is stamped. In addition, the authors' basic assumption that the two sister ships were almost completely identical and therefore easily interchangeable is incorrect. Furthermore, the insurance sum of one million pounds sterling did not by far compensate for the damage to the White Star Line's image caused by the disaster.
Possible influence of weather conditions
Some theories also deal with the question of whether the weather conditions and meteorological conditions at the time had an influence on the catastrophe.
Astrophysical reasons
Donald Olson, a professor of astrophysics at Texas State University, theorizes that various astrophysical phenomena are responsible for the southward migration of the icebergs. In January 1912, he says, the full moon came closer to Earth than it had in 1,400 years; moreover, the Earth was at perihelion and formed a common line with the sun and moon. All this is said to have led to the forces and gravitational thrusts at work causing an unusual tidal range, which freed icebergs broken off in Greenland and stuck in the shallow waters off Newfoundland and Labrador and moved them southward, for example by getting the icebergs into the Labrador Current. This explains the unusually high number of icebergs in the area of the 42nd parallel.
According to a report by Lane Wallace, the position of icebergs is unlikely to be influenced by the tidal range, but rather by a complex system of ocean currents and weather conditions. The travel time of ice pieces from Greenland to the area of the 48th parallel is 1-3 years anyway. In addition, high, sometimes significantly higher iceberg numbers were also recorded in the years before and after. Rather, the reason for the many icebergs was the harsh winter of 1912.
Super Refraction
According to an investigation by Tim Maltin, a special optical phenomenon, a super-refraction, prevailed on that April night. Due to the thermal inversion, a layer of air cooled by the cold Labrador Current lay below a layer of air warmed by the warm Gulf Stream. Due to this effect, light was reflected unusually strongly, and a false second horizon was formed above the real one. A haze formed in between, which was also noticed by the two sailors Lee and Fleet in the crow's nest. The calm sea also blurred the area between the two horizons, so that the iceberg "disappeared" below the false horizon the sailors were looking at. Consequently, the iceberg was not discovered until it was too late.
This same super-refraction also made distant objects appear closer, which is probably
why the crew of the Californian perceived the Titanic as a small and close ship. The signal rockets fired there probably appeared to be too small in view of the supposed small size of the ship, so they were not perceived as important enough. Furthermore, the emitted Morse signals could not penetrate through the layers of air to the Titanic.
The watertight bulkheads - Why the Titanic was not unsinkable
To this day, the term "unsinkable" is inseparably linked with the Titanic. This predicate had already been used as advertising for various ships a long time before. The Great Eastern of 1860 was already divided into many watertight compartments. However, the extreme subdivision with high bulkhead walls without any opening resulted in considerable losses in terms of passenger comfort. Since the Great Eastern was unsuccessful as a passenger ship and only made money as a cable liner, no shipowner dared to build a ship with an uncompromising focus on safety. Instead, passenger comfort became the focus of interest.
The watertight subdivision of ships was then, as now, a compromise between safety on the one hand and economic usability and construction costs on the other. As early as 1891, a "bulkhead committee" had published comprehensive recommendations for the watertight subdivision of ships. Consequently, no particular innovations were introduced in the watertight subdivision of ships on the Titanic; only the twelve automatically closing watertight doors on the tank-top deck were of a novel design on the Olympic class.
Contrary to today's frequent mention of the Titanic's alleged unsinkability, this word was only published twice in articles about the ship prior to her sinking, moreover with the qualification "practically" or "as far as possible". Nor was the word "unsinkable" used by the designers of the Olympic class, nor was it intended to make the ships "unsinkable".
The watertight subdivision was constructed as follows: Above the keel was a cellular double bottom, nearly two feet high, consisting of 44 watertight compartments. Above the inner floor were 29 further compartments, 16 of which formed the large main sections (see picture), which were laid out according to the so-called two-compartment standard. This means that if any two of these 16 compartments next to each other had been flooded at the same time, floatability would never have been compromised. According to the rules of the bulkhead committee, in view of the dimensions of the Titanic, the upper ends of the bulkheads (more precisely: the bulkhead deck) would still have had to be at least 20 centimetres above the waterline in the event of such flooding, taking into account possible impact sides. In fact, the bulkhead deck was at least 75 centimetres (significantly more in most combinations) above the waterline in two-compartment flooding, so that, as recent calculations have shown, she would have met the criteria for flooding three compartments side by side in 11 out of 14 possible cases.
In 4-compartment flooding, the bulkhead deck was still above the waterline in four cases (the forward four as well as the aft four compartments and two combinations involving Boiler Room 1). And even with all forward five compartments flooded, Titanic would very likely have stayed afloat for a very long time, at least under the conditions on the night of the disaster. A longer floatability with simultaneous flooding of 6 of the 16 watertight compartments, as happened after the collision with the iceberg, was however in no case mathematically possible. Such extensive damage to the ship as a result of an accident has only occurred once in the history of shipping. For "normal" damage, such as that caused by collisions with other ships or running aground, a two-compartment standard combined with a double bottom was completely adequate.
Attempts to keep ships with even more extensive damage afloat would not only involve difficulties in watertight subdivision and place enormous structural demands on stability. Measures that would help in one case could have potentially fatal effects in other damage, such as capsizing. After the sinking of the Titanic, such an attempt was made with its sister ship, the Britannic. However, during World War I, it became apparent that under unfavorable circumstances, even a single mine was sufficient to sink the Britannic. Also in World War I, the Lusitania ("as unsinkable as a ship can be") sank due to damage from a single torpedo and the secondary explosion it triggered. What remains particularly noteworthy about Titanic's watertight compartmentation is that it still allowed her to remain stably afloat even under advanced flooding. Normally, ships develop strong list under such conditions, which makes an orderly evacuation almost impossible.
After the First World War, more work was done on improved evacuation possibilities, as it was realised that it was not possible to maintain the buoyancy of heavily damaged ships indefinitely.
The breakup
It is still unclear how exactly the Titanic broke apart. After a model analysis using finite elements on behalf of the Marine Forensic Panel, the renowned American ship design firm Gibbs & Cox Inc. came to the conclusion in 1996 that the stern of the Titanic protruded from the water at a maximum angle of between 15° and 20° and then broke away from the main part of the ship due to the excessive structural loads.
The TV station "History" started another expedition to the wreck with the Woods Hole Oceanographic Institution in 2005. For the first time, the eastern part of the wreckage was also examined. Two parts of the double bottom with a total length of almost 18 m were found. They were completely preserved over the whole width of the ship. This was recognized by the existing sling keels, which were perfectly preserved on both sides of the finds and in places still showed the red colour of the last coat of paint. Based on the video recordings made, it was possible to determine that the two double bottom pieces found matched at the break ends.
A closer look at the double bottom parts led to the new assumption by Roger Long that the ship broke apart differently than previously assumed. According to Long's considerations, the double bottom would have been compressed in the previous model, while the upper decks of the Titanic would have broken apart cleanly at this point. On the wreck, however, it can be seen that at the point of rupture the decks are pulled downwards and do not have a clean break. However, the ends of the upper decks at the break points could also have been bent downward by the force of the impact with the ocean floor, as there was no structural stability left due to the tremendous damage at the break points. This can be seen very well, for example, on the stern section of the Titanic wreck, whose upper decks are completely destroyed.
Long theorized that Titanic's stern began to break off when it was still relatively low out of the water at about 11°. According to this, the breakage started at the upper decks and extended to the keel. However, the stable keel - the backbone of any ship - initially prevented the stern from breaking off. Through the crack in the outer skin of the Titanic, considerably more water was then to penetrate, so that the sinking of the ship was accelerated. At the point of rupture, the bow, which was under water, now pressed against the stern, which was rising above water, so that the decks at this point of rupture were crushed. However, Long's arguments fail to show why this compression should not have happened at a slightly greater angle. The finite element analysis only extends to the point where the hull was still in one piece. The dynamics of the breakup with the incalculably increasing leakage area are probably hard to calculate. A quantitative explanation of how exactly the angle of 11° comes about has not yet been published.
