Until Robert Ballard published his magnificent photography of the wreck (The Discovery of the Titanic, Toronto: Madison Press Books, 1987), the generally accepted theory was that the underwater hull of the ship was ripped open for some 300 feet during her encounter with a large iceberg. After several hours of progressive flooding, she slid below the sea, bow first, and sank substantially intact. This was the conclusion of 1912 investigations into the disaster by a U.S. Senate hearing and a British Board of Trade investigation. Only a few of the survivors— including then-16-year-old John Thayer, then-7-year-old Eva Hart (who passed away in March 1996), and then-25- year-old Elmer Taylor—disputed some of the conclusions.
The pictures brought back from the wreck site in 1985 and 1986 begged explanation. The wreck of the Titanic is in two large pieces, 1,970 feet apart, with much of the midships section missing and a large debris field between the two hull sections. While the forward section is largely intact, the separate stern section has collapsed, with a substantial portion of the upper decks ripped apart.
New probes of the sinking process have been aided by information and photography from five expeditions to the wreck site, most important of which—at least for forensic purposes—was the 1991 IMAX expedition, which brought back samples of steel from the debris field. Subsequent metallurgical tests were conducted under the auspices of the Bedford Institute of Oceanography (BIO) in Dartmouth, Nova Scotia, assisted by the Metals Technical Laboratory, and the P. P. Sirshov Institute of Oceanography in Russia. BIO’s Stephen Blasko, the 1991 expedition’s chief scientist, said in April 1993 that the steel of the Titanic was more brittle than that used today. We shared this conclusion in papers submitted to the Society of Naval Architects and Marine Engineers. Although many modern merchant ships use steels that are brittle at low temperatures, there is no legal requirement for notch-tough steels by the classification societies that regulate their construction. Notable here also is that the steel used in the Titanic is probably no worse than the bottom end of some of today’s steels. Based on these findings, a brief account of the Titanic’s final two-and-a-half hours can now be told:
Captain Edward Smith made course alterations toward the south from 1145 to 1152 on 14 April 1912, based upon ice warning messages received that morning. During the evening, as the Titanic made her way westward, the ship received nine serious ice-warning messages from other ships. Among these was an important radiogram from the liner Mesaba at 2140, warning of large icebergs, pack ice, and much field ice in latitude 42° to 41.25° North and longitude 49° West, which was precisely in the track of the Titanic. Because of a typing error, the message having been signed “MXG” instead of “MSG” (Master must sign), the navigating officer never saw it.
At 2230, the eastbound cargo ship Rappahannock sent a Morse code message advising that several large icebergs and heavy field ice were astern and that she had sustained damage to her rudder. Personnel on board the Titanic acknowledged the message. At 2255 the cargo-passenger ship Californian radioed all ships that she was at a halt and surrounded by ice. Since she was close to the Titanic’s position, her radio message was strong and interrupted the Titanic's own radio transmissions. The Marconi radio officer on the Titanic responded to this signal, adding, “Keep out! Shut up! You’re jamming my signal. I’m working Cape Race.” At 2335, radio operator Cyril Evans in the Californian shut down his radio for the night. At this moment, the Titanic was speeding westward at 21.5 knots in an absolutely calm sea on a very dark and moonless night toward the very ice field that was surrounding the Californian.
Around 2340, in the crow’s nest on the mainmast, lookouts Reginald Lee and Frederick Fleet noticed a slight haze ahead and attempted to determine what lay in the path of the ship. Unfortunately, they had no binoculars to sharpen their vision. Finally, Fleet was able to make out the dark outline of an iceberg, rang the bell in his position three times, and phoned the bridge to advise of his sighting. The Titanic veered some 20° to port, as the first officer, William Murdock, ordered the helmsman to make a port turn. The ship took some 30 seconds to respond to helm over a distance of a quarter-mile. Murdock then gave an order to stop and reverse the engines and followed with a desperate attempt at a starboard maneuver to avoid a collision with the iceberg. It was too late.
Accounts of survivors vary on the severity of the Titanic’s encounter with the iceberg. From the crew and passenger narratives we have reviewed, the size of the ice mass had a displacement of between 180,000 and 300,000 tons, with about 85% of its mass below the water surface. From the crow’s nest, noise was minimal—only ice could be heard falling onto the deck below. Inside the ship, several survivors noted a scraping or bumping noise as the iceberg slid by astern. Officers and crew on the bridge noted a long, grinding-type impact during the slow turn to port. Thomas Andrews, naval architect and managing director of Harland and Wolff, the shipyard that designed and built the Titanic, noticed a slight jolt. Accounts vary on the severity of the collision, but some of the passengers were aroused and began to walk out to the open decks to determine what had happened. Eva Hart’s parents were startled by what she described as a sharp bump, and her father made a tour of the boat deck.
During the early phases of the sinking, passengers and some crew would not believe the ship was in danger. Not until an hour after the iceberg was hit did passengers begin appearing in large numbers on the boat deck to board the few lifeboats that were left. In a November 1993 television interview, Eva Hart noted the desperation of these people based upon their screams and movement of their feet on the boat deck. As the bow sank farther into the icy cold waters of the Atlantic, the radio operators, Jack Phillips and Harold Bride, sent out a distress call, hoping that a ship would come and pick up the passengers and crew.
At approximately 0145, the bow started to go under, and the stern began to rise clear of the water until it reached an angle of 45° to 60°. A loud noise shortly after 0200 preceded the sudden extinguishing of the lights that had shone so brightly. According to some survivors, including Eva Hart, the stern fell back toward the surface, only to rise again to a steep angle. It then slid below the surface, taking 1,517 passengers and crew with it.
The size of the opening caused by the collision with the iceberg has been described for many years as a longitudinal opening some 300 feet long and several inches wide. Such damage is not evident on the wreck, based on reports from all the expeditions, and it is not consistent with the rate of flooding. Moreover, steel cuts ice, but ice does not cut steel. We now conclude that this gash is nothing more than folklore. Mr. Edward Wilding, who was head of the design team under naval architect Thomas Andrews, testified before Board of Trade hearings that his calculations estimated the initial flooding area amounted to less than 12 square feet. We believe his assessment was essentially correct, based on our forensic studies. As the ship sank deeper into the water, the areas damaged by the iceberg above the waterline presented additional sources for flooding, as well as the spillage of water from those flooded compartments into the next adjacent ones. The Titanic struck the iceberg at 2340 on 14 April and sank around 0220 the following morning. The slow rate of flooding in the initial phases of the sinking was fortuitous; a more rapid rate of flooding would have caused an even greater loss of life.
Important in the damage assessment is that Andrews, after personally inspecting the flooding of forward compartments, suggested that Captain Smith begin evacuation of the passengers immediately. What he might have seen was a myriad number of tiny cracks in the shell plates, small fissures radiating from rivet holes, and displaced riveted seams that were allowing sea water to come in, not as an incoming tide, but a continuous spray. Unfortunately, the evacuation did not start immediately.
The 1986 Ballard Expedition found and the 1987 IFRE- MER (Institut Français de Recherche pour l’Exploration des Mers) and 1991 IMAX Corporation explorations confirmed the existence of a large hole in the starboard bow portion of the wreck, which has fueled further controversy. The hole is located around “G” (lower) deck, above the waterline and just below the cargo cranes in way of the mail hold. After correspondence with some members of the 1993 IFREMER Expedition, we concluded that this hole may have been punched by a final blow from the iceberg. It was not made by any explosion because of the rather pristine condition of a vertical ladder in way of the hole and the lower deck bounding the bottom half of this hole. Substantial shell deformity is evident at the lower half of this hole, with the plate buckling with folds oriented outward and the upper half covered by rusticles, which give the hole a rather jagged appearance. We believe the iceberg created the hole and that the collision weakened the riveted connections. The impact of the bow portion hitting the sea bed ripped holes open in the starboard and port sides. The torn upper half owes to a combination of tom rivet holes in the plating, which was, perhaps, weakened further by the brittle fracture nature of the steel in the icy cold waters of the Atlantic at the time.
One of the most puzzling problems for those assessing the loss of the Titanic has been to determine the degree and extent of damage from her collision with the iceberg. During Ballard’s tour of the starboard side of the bow section in the Alvin, he was able to observe some evidence of damage from the iceberg. In his book, Titanic: An Illustrated History (Toronto, Ontario: Madison Press Limited, 1992), Donald Lynch explains that the initial flooding may have been caused by the failure of the rivets, which opened up seams to allow water to enter the hull. With the ship proceeding at 21.5 knots, the iceberg encounter probably was a series of glancing blows that caused plating to buckle or tear and rivets to fail in shear, or by elongation, which broke the caulking. The breaking of the caulking and opening of riveted seams and plate tearing was enough to allow sea water to stream in. In addition, the brittle nature of the Titanic’s steel in such icy cold waters—as indicated by tests done on steel recovered from the wreck site—and its low resistance to impact loads, as well as the forces caused by the progressive flooding, could have contributed to the hypothesized rivet and plate failures. The rivets also were cold punched, creating microscopic cracks around the periphery of rivet holes.
Based upon testimony of stoker Frederick Barrett from Boiler Room No. 6, water gushed into this space from what appeared to be an opened seam two feet above the floor plate. No such hull opening could be seen in examinations of the bow portion of the wreck during the 1993 expedition. We attribute this flooding to the aftermath of a coal fire in the reserve coal bunker forward of this boiler room. The fire was extinguished the day before the ship sank, but it had been raging from the time the ship left Belfast. Such a fire within a structure immersed in cold water can turn steel into brittle martensite, and when the iceberg made its parting shot at the Titanic, the steel at the juncture of the bulkhead and side shell crumbled, allowing sea water to pass into the boiler room.
The location of the main hull fracture has been a mystery because of missing material in the area around the third stack. It now seems from the pictures of the wreck that the upper decks and superstructure failed in tension, while there was a buckling failure in the plating of the inner bottom and shell from the massive amount of flooding water in the bow’s first six watertight compartments and the two heavy reciprocating engines in the over-hanging stern portion when it rose clear of the water surface. The initial break began in “B” Deck (strength deck) between the compass platform support and the third funnel around the termination of the second expansion joint. This possibility is supported by the fact that the transverse girders in way of the expansion joint as well as forward of the reciprocating engine room were spaced at 9 feet, while from the reciprocating engine room aft, the spacing was changed to 6 feet. These structural incongruities, the rather small radius cuts in the side shell, and the expansion joint termination at the strength (“B”) deck increased the stress level in the area of the third funnel when the stern came clear of the water. When the 28° to 31° sea water made contact with the overstressed structure aft of the compass platform, the structure in way of the third funnel failed massively. Survivors in the lifeboats noted rumbling or cracking noises as the ship began to slip below the water surface. A review of the photography from the wreck site and the illustrations of the bow wreck reinforce our conclusion that brittle fracture was involved in the breakup.
When the ship took a 45° bow trim, the boilers in No. 1 Boiler Room below the transverse deck girders came loose because of a buckling failure in the plates of the inner bottom, which sheared the rivets and bolts in the boiler foundations. Once the boilers came free, they plunged to the sea bed below when the ship started to split apart. These boilers are the ones the 1985 expedition found that helped locate the wreck.
Sections of oak wood paneling from the first-class lounge and one of the first-class staircases offer evidence of the violent nature of the hull failure. The decks were bent downward and the sides were compressed inward. This decrease in structural strength was exaggerated by the numerous openings in the area, plus the expansion joint just aft of the third funnel. The latter would have had extreme stress concentrations because of the bending stresses caused by the bow flooding, and the low water temperature would have put steel of that vintage into the brittle-fracture zone, implying that the ultimate failure was at a lower stress. This theory on the hull failure has been reinforced further by the writings of Elmer Taylor, one of the survivors in lifeboat number 5, which was about 450 yards from the sinking ship when she broke apart. He wrote, “The cracking sound, quite audible about a quarter of a mile away, was due, in my opinion, to tearing the ship’s plates apart, or that part of the hull below the expansion joints, thus breaking the back at a point almost midway the length of the ship.”
One theory, suggesting that the failure in the stem (implosion) owed to the collapse of air-filled compartments— the pressure of which had not reached equilibrium with the outside water pressure as the ship sank—is supported by the fact that the large refrigerated hold was in the after portion of the ship and flooded very slowly. It would have taken some time for the flooding to have occurred, and this would have made implosion almost a certainty. The structural boundaries likely began to fail at approximately a 30-foot differential head, followed by a more rapid collapse at a somewhat greater depth. Examination of the pictures and the ship’s arrangements suggest that this was almost certainly the cause of the collapse of the stem. The devastation is worse in the region of the refrigerated hold and the ship’s refrigerated space. The sides at the forward end of the stem section of the wreck collapsed inward, possibly from a similar cause, which would suggest that flooding adjacent to the region of the break may not have been extensive.
Based upon the photography of the Titanic wreck, the main hull failed at the surface. Just before the split in the hull took place, the lights, which had shone so brilliantly, were extinguished. Professor John Woodward theorizes that steam lines to the generators in Boiler Room Number 1 had been ruptured, cutting off fuel to the lights. We think, however, that the failure of the hull girder came before the steam line break, and the hull failure certainly would have snapped the main cable between what is now the bow and stem. Those portions were separated above the inner hot- tom, but when the bow section became weighted with water after being totally submerged, it hinged down. This bending brought about failures in the boiler foundations in Boiler Room Number 1. The stem section, mostly free of the bow and still buoyant, fell back toward the surface. Because of 15 tons per square inch of stress in the region of the third stack, aggravated by stress concentrations around the expansion joint and the large openings in the area, the steel disintegrated, causing this stack’s stays to fail and ultimately allowing it to fall into the water, killing some survivors in the area. At this moment, 17-year old Jack Thayer was thrown into the sea by the force of the rupture.
The stem first fell back toward the surface and then rose again as its forward compartment (the reciprocating engine room) began to flood and the dead pull of the bow, still attached, started to take it below the surface. The stem listed slightly to port, then rotated slightly before it disappeared. The rotation was also accompanied by a rattle and groaning as the steel being twisted continued to fail. The ship, then almost in two sections, began her quick plunge toward the sea floor. The buoyancy of the stem and the deadweight pull of the bow (estimated to be 15,600 tons of negative buoyancy) exerted a tremendous force on the weakened sliver of inner bottom structure holding the two sections together. At some distance well below the surface the two sections finally separated, and, because there was insufficient time for water to enter the stem portion and equalize pressures, it imploded. This was aided by the intense water pressure exerted on the after watertight bulkhead of the engine room. This bulkhead folded into the stem. The key factors in the hull failure at the surface were the brittle fracture with the high tensile stress and the loss of transverse rigidity around the second expansion joint, since the transverse web frames had been weakened by displaced boilers.
The two main portions of the wreck came to rest 1,970 feet apart some 12,500 feet below the surface. This separation is not great for irregularly shaped pieces of wreckage and gives credence to the theory that the final break occurred some distance below the surface. At the point of final failure, the bow portion was fully flooded and the stem portion still had some buoyancy.
There was no question that with 6 of the 16 major watertight compartments involved in the initial damage and flooding, the ship could not stay afloat. Finally, credit should be given to the Boiler Room No. 1 and Dynamo Room crews, who labored to the end and kept the lights on. None of these men survived; they were faithful to their duty even in the face of death.
The Titanic and her sisters represented a great leap in steel ship construction and technology. Unfortunately, brittle fracture of steel in ships was an unknown phenomenon at that time. The steel used in these ships was a standard state-of-the-art type for that period, produced by one of Great Britain’s premier steelmakers, D. Colvilles and Company, Motherwell Works. Not until World War II, after the failure of Liberty ships and T-2 tankers, was brittle fracture of steels at low temperatures in ships recognized and better understood. Using riveted joints to arrest crack growth, notch-tough steels, and careful examination of steel grain size by the classification societies began to rectify the problem. In 1947, the American Bureau of Shipping introduced restrictions on the chemical compositions of steels.
The cause of the Titanic disaster owed officially to the ship’s proceeding at dangerously high speed in an area known to be ice-prone. It also appears that the crew of the ship was overly confident in the Titanic’s ability to take damage. Neither the shipbuilder nor the crew was aware, however, that the steel of the Titanic lost all its ductility and became brittle at the water temperatures the ship encountered on 14 April 1912.
The Titanic disaster created a legacy for the maritime profession. Subsequent U.S. and British inquiries led to improved subdivision of ships, increased lifeboat capacity, the mandatory 24-hour manning of radios on board ships, and the creation of the ice patrol to prevent recurrences of the terrible tragedy. In 1913 and 1914 nations of the world met to discuss measures to improve ship subdivision and safety. World War I intervened before ratification and not until 1929 were these measures adopted at the first Safety of Life at Sea Conference. The successful rescues of 1,662 passengers and crew from the Italian Lines Andrea Doria in July 1956, some 700 passengers from the Holland American liner Prinsendam in 1980, all crew and passengers from the Soviet cruise ship Mikhail Lermentov in 1986 and Greek cruise ship Oceanos in 1992 point to the effectiveness of the measures that have been adopted for ships at sea since the Titanic disaster.