Time Line of Titanic Descent
At 11:50 p.m., ten minutes after impact, 4,000 tones of water have entered the first five watertight compartments through twelve square feet of iceberg damage. Fireman Fred Barrett notes that water is entering the sixth compartment through a small hole behind the forward bulkhead of boiler room five. The water "enters five as if through a fire hose," but the pumps are able to handle it.
12:00 a.m. Twenty minutes after impact, 7,000 tons of water have entered the Titanic's bow. The bulkhead between boiler rooms five and six, already embrittled and partly melted by a coal bunker fire, and warped by the lateral thrust of ice, is further weakened by increasing water pressure in boiler room six.
12:20 a.m. Forty minutes after impact: Two rows of portholes are now under the sea (and soon, Lightoller's gangway door). More than a half dozen of those portholes are open, increasing by at least 50% the original twelve square feet opened to the sea by the iceberg. Even so, the ship is settleing toward stability, at which point the sinking process slows to a near halt.
12:40 a.m. An hour after impact, water rises of the closed hatch at the top of boiler room five and creeps alt along the hallways. The first boat, number seven, is being lowered on the starboard side.
12:45 a.m. As the first distress rocket is fired, the forward bulkhead collapses in boiler room five.
This critical bulkhead, weakened by fire and ice, was essentially a fuse waiting to be ignited. Boiler room five becomes the first falling domino in an escalating and ultimately catastrophic chain reaction.
1:20 a.m. On the port side, water is flowing in through Lightoller's open gangway door and running aft along Scotland Road (A wide corridor that ran almost the entire length of E Deck, along the port side) . The ship is now listing to port. During the past thirty-five minutes, since the collapse of boiler room five, water has been spilling down stairwells on either side of Scotland Road. With the gangway door now providing a wider opening to the sea that the initial iceberg damage, nothing except the buoyancy of boiler room four keeps the Titanic stable.
2:00 a.m. Two hours and twenty minutes after impact. Rowing along the starboard side, Mrs. Thayer notices a porthole open to the sea, and watches a cabin flood as the opening glides under. She realizes, with a start, that portholes left open by passengers who looked outside after the crash have increased the rate of hemorrhage. Third-class men are released from the stern at this time, an hour after first class dogs were released from the ship's kennel.
2:05 a.m. Hundreds of square feet are now opening to the sea along the upper decks. The hatch at the top of boiler room four has been closed for more than an hour, providing a brief respite to men working the pumps below - unaware, apparently, that they are working in a submarine.
2:10 a.m. Building water pressure bursts boiler room four. The final plunge begins.
2:11 - 2:14 a.m. The entire five-story structure of the Grand Stairway becomes buoyant and breaks away from its mountings, presumably in large pieces. The afterstays for the first smoke-stack, attached to the spine of the stairway, are severed.
As the Titanic's bow plunges under, Scotland Road and other avenues of seepage stop transmitting water aft and send a storm surge forward. Washington Dodge notes that water jets out through a window actually located above sea level. Charles Lightoller notices that the roof of the bridge, when it reaches the sea, is level with the crow's nest.
2:15 - 2:17 a.m. Boiler room three collapses. Eugene Daly sees dozens of swimmers about to be drawn down into the second smokestack. Below the surface, Colonel Gracie struggles near the compass tower between the second and third stacks.
2:17 a.m. The sea surface becomes a fulcrum, snapping the Titanic just abaft of amidships. Between the reciprocating engine room and boiler room two, an eight-foot length of hull and decking (including the kitchen floor on D deck and the double-hulled floor of the engine rom and aft boiler rooms) cracks into hundreds of pieces, like glass. Drifting below the surface, just forward of the break beneath the toppling third smokestack. Colonel Gracie makes one of history's narrowest escapes.
2:17 a.m. Given what appears to have been a 'clean' breakaway, the stern should have floated; but the crew's attempts to pump water out of the forward compartments through hoses attached to the aft engines have left the door at the bottom of the turbine room open, permitting water to gush in from the reciprocating steam engine room. The passengers might have fared better had the engineers done absolutely nothing to save the ship. . . might have, if not for the hot coals spilled from the smoking room fireplace during the forward plunge. The stern is now burning and sinking.
2:18 a.m. Thirty seconds after the break, the open doors allows the sea to flood the engine rooms, bringing the forward section of the stern down to E deck.
2:18 - 2:19 a.m. As the E deck passageway outside Joughin's stateroom floods the aft extension of Scotland Road, the stern rolls briefly onto its port side, then corkscrews "nose down." Furnishings, tools, fittings - even ashtrays from the first-class smoking room - begin raining from the nearly vertical opening. The last good news anyone will hear aboard the Titanic : the fire has been put out.
2:20 a.m. As water fills the stern, the last air pockets begin to compress. Refrigerator doors break. A few chambers, unable to fill quickly, undergo partial crushing, like beer cans, until the moment of breach. By the time the stern reaches a descent rate of fifteen miles per hour, drag forces are peeling back the fantail decking and trying to wing the keel level again.
2:23 - 2:24 a.m. After falling two and one - half miles, the stern arrives on the bottom propeller end first, having reached a terminal velocity of at least thirty-two miles per hour, probably as high as forty miles per hour, and possibly as high as fifty or even sixty miles per hour.
2:24 a.m. As the propellers impact against hard sediment, the stern bends, compresses, and cracks all the way forward - all in the space of two seconds. The slipstream of water that follows the stern is still descending at the same terminal velocity achieved by the wreck before it stopped. The effect of the resulting downblast against the upper deck is like a tidal wave striking a skyscraper. Within the stern, inertia continues to push water toward the seabed where, finding its path suddenly blocked, it bursts out the sides and contributes to the formation of an ejecta blanket.
2:22 - 2:24 a.m.
Relative to the stern, the Titanic's bow glides to the bottom. Nevertheless, it reaches a terminal velocity of at least twenty-five miles per hour, probably somewhere between twenty-five and thirty miles per hour, and possibly as high as thirty-five or even forty miles per hour. The nose plunges more than sixty feet into the sediment, crumbling as it descends.
2:22 - 2:24 a.m. Below the bridge, the hull bends like according skin and double bottom is actually telescoped aft into boiler room six, rendering the archaeologist's separation of iceberg damage in this region from the bottom impact damage an intractable problem. The only likely signs of iceberg damage are observed further aft: a) a twelve-foot-long horizontal scratch (apparently made by a small rock within the ice) drawn like a pencil point, during one third of a second, across the centers of three hull plates, and just ahead of the scratch; b) a hole, the approximate size and shape of a plumb, near the bottom of boiler room five. A second after the bow levels out on the bottom, the downblast strikes, hammering down rooftops, pancaking decks, and (except on the narrowest deck profiles, near the point bow) blowing railings out to port and starboard.