A reevaluation of the fatal collision.
All of that turned out to be myth and legend.
Late at night I often found myself too excited to sleep as Titanic's crew spoke to me through their 1912 testimony. Time after time I would suspect a quartermaster, fireman or lookout of lying -- only to find overwhelming evidence supporting those claims. It became obvious to me that the events experienced by the crew were not those etched into history by either the U.S. Senate or the British Board of Trade inquiry.
No "Crash Stop"
According to Fourth Officer Boxhall, First Officer Murdoch changed the orders to the two outboard propellers from AHEAD FULL to ASTERN FULL, requesting what sailors call a "crash stop." This is a violent maneuver that can damage the ship's engines, drive shafts, or propellers. For that reason, it is reserved only for the worst of emergencies. Testifying in London, Boxhall said the engine order telegraphs read "full speed astern" when he stepped into the enclosed section of the bridge.
Unfortunately Boxhall's recollection seems faulty. Titanic never attempted the crash stop that people on land still believe was the obvious way to prevent the ship from slamming into the iceberg. Reverse thrust from the propellers would have eliminated the ability of the single rudder to steer the ship. Murdoch knew this. Under full reverse power the ship could not have pivoted to the right, but would have begun a sideways slide into the iceberg
The toil of those sweaty men feeding the fires in the ship's boiler rooms was by red warning lights and clanging bells moments before the accident. "Shut the dampers," sang out Leading Stoker Frederick Barrett. He and Second Engineer James H. Hesketh had been talking in Boiler Room #6 when the alarms clanged and the lights on the stoking indicators changed from white to red. Chatter among the men stopped in mid-sentence as they turned to this unexpected work. Closing the dampers on the furnaces was an ordinary precaution to reduce the fires to prevent generating excess steam pressure while the engineers stopped the engines. There were safety valves, of course, but these were not foolproof and had been known to stick on occasion. Nobody wanted to risk building up excessive steam pressure.
The command to close the dampers came just prior to impact when Titanic was perhaps 700 feet from the berg. Closing the furnace dampers is yet another indication that a crash stop was never performed. Full reverse power would have required as much steam as possible from the boilers. Shutting the dampers would have been the worst possible thing to do during a crash stop. Instead, stokers would have been asked to rake the coals in their furnaces to increase steam output from the boilers in order to get maximum power out of the engines.
Titanic's engines and associated drive shafts and propeller blades were designed to withstand an instant shift from forward into reverse at harbor speeds. They might have had strength enough to withstand the strain of instant reversal at 22.5 knots, but only if every part from cylinder to tail shaft was totally free of defects. Ships have been known to snap shafts and propeller blades during crash stops. If nothing broke on Titanic, a crash stop would have caused a rumbling shudder to convulse through the after third of the hull.
In 1951, the U.S. Navy aircraft carrier Tarawa was passing through the Straits of Messena. A passenger ferry suddenly cut across the warship's bow. "All back emergency!" was the instant commande and the carrier's engines began pounding in reverse. The stern of the ship began jumping up and down, some of the crew later said the jumps were six feet or more. The collision was avoided. Next morning, dozens of the carrier's crew were sporting slings, casts and neck braces from being flung to the deck by their ship's successful "crash stop." So much china was broken by the maneuver that it was necessary to put into port to buy more in order to feed the crew. Within a few weeks, the ship itself was drydocked to repair damage done to the at least one propeller shaft.
Since none of the seven-hundred Titanic survivors described such a memorable event, and because the firebox dampers were ordered shut, the engineers could not have performed a crash stop
3. They just closed the throttles to the engines to stop them from pushing the liner forward. In sailor terms, Titanic was "shooting," or coasting forward without power when it contacted the iceberg.
Where was the fatal ice damage done to the ship? "To the side," history has answered for 88 years--despite both the physical impossibility of such damage and the direct testimony to the contrary by members of the crew. Scenes in the movies show the starboard bow of the giant liner slamming against a wall of ice much like an automobile sideswiping a highway bridge abutment. Nothing could be further from the truth. If the ship had collided with the berg in that manner, the impact would have been devastating. Men sleeping in the bow would have been thrown out of their bunks to the hard steel decks. Anyone standing in the grand First Class entrance likely would have had their feet knocked from beneath them. Certainly there would have been dozens (if not scores) of injuries: broken arms, legs and even skulls. More than a few people would have been killed outright as the steel bow collapsed around them.
None of that happened.
With full right rudder (port helm in 1912) Titanic was turning to the right as it contacted the ice. There had been those few quick seconds when it appeared the daring S-curve would succeed. However, as every child learns in school, the bulk of an iceberg lies beneath the water. Murdoch knew it, too. He fully expected what happened next. Titanic's fragile underbelly scraped across an underwater shelf called an "ice ram." These shelves are common enough to warrant special attention in Bowditch. "It is dangerous to approach close to an iceberg of any size because of the possibility of encountering underwater extensions," the navigation text cautions. The great danger of icebergs is "underwater extensions, called rams, which are usually formed due to the more intensive melting or erosion of the unsubmerged portion."
Physical evidence and eyewitness accounts point to the accident being a grounding, not a collision. Titanic did not run into an iceberg; it ran over an iceberg. The initial pattern of flooding and testimony from surviving crew members are consistent on one point: the bottom of the ship--not the side--made solid contact with the ice. Survivors unanimously described the sound and vibration of a ship running aground. There was no sharp jolt of a ship slamming horizontally into an immovable object. Instead, the slight tremble was barely enough to rattle silverware set out for breakfast in the First Class dining saloon.
The difference between a grounding and a collision is far more significant than it appears. Head-on impact with the berg would have sent all of Titanic's 52,310 displacement tons
5 smashing into the ice at a speed of almost 36 feet per second
6. In the crunch of a head-on impact, the ship's speed would have effectively dropped to zero. Everything inside the bow that was not tied down--people, chairs, bottles of wine, soup tureens--everything would have continued moving. Sleeping immigrant men near the bow would have been sent flying out of their bunks. Farther aft, the impact would have been less, but still substantial. Women could have been hurled down the grand staircase in First Class to land twisted and broken in a pile of taffeta. In the Second Class smoking room behind the fourth funnel men might have felt their chairs move beneath them.
Edward Wilding, one of the naval architects who designed Titanic, testified in London about the effect of a head-on collision. "If she struck a fair blow I think we should have heard a great deal more about the severity of it, and probably the ship would have come into harbor," he said. "I am afraid she would have killed every firemen down in the firemen's quarters, but I feel sure the ship would come in." At the U.S. Senate hearings Captain John J. Knapp, the U.S. Navy's hydrographer, tried to imagine such an impact for Senator Smith:
MR. KNAPP: ...an idea may be formed as to the possible blow by using the accepted formula, the weight multiplied by the square of the velocity divided by twice the gravity. Multiplying...will give the blow that would have been struck if she had kept straight on her course against this apparently solid mass of ice, which, at a speed of 21 knots, would have been equal to 1,173,200 foot tons, or energy enough to lift 14 monuments the size of the Washington Monument in one second of time.
-- U.S. Senate Hearings
May 18, 1912
Naval architect Wilding raised an interesting point about a head-on accident involving an extremely large ship. The bow of Titanic would have crumpled much like the "crumple zone" of a modern automobile. Crumpling would have absorbed much of the force of the blow by spreading it out over time. According to Wilding, telescoping of the ship in this manner would have reduced injuries among the passengers and crew who were lucky enough not to have been trapped in crumpled sections of the bow.
While less dramatic, the more often invoked "glancing blow" at 22.5 knots would have created its own kind of havoc. At impact, the deck would have jumped sideways relative to anything not rivetted to it. This "rebound effect" should have been as disruptive to people living in the forward third of the ship as a major earthquake in a large hotel ashore: sleeping Third Class passengers tossed to the hard steel decks; personal items tumbled off shelves; people thrown down. There would have been fewer injuries and less spilled drinks than during a head-on collision, but some deaths and broken bones. Either type of horizontal impact--head-on or glancing blow--would have been unforgettable from the point of view of a passenger. None of the more than 700 survivors remembered as dramatic as either a head-on or "glancing blow" impact that happening.
What a sailor calls "rebound" is known scientifically as "impulse and momentum." These are the words naval architect Bill Garzke used to explain the traditional bow sideswipe to the Discovery Channel. He envisioned the hull striking the ice, then rebounding to strike again...and again...for nearly 300 feet along the bow
7. Garzke's description of events may have been inspired by Lightoller who described essentially the same type of accident in his autobiography.
The impact flung her bow off, but only by the whip or spring of the ship. Again she struck, this time a little further aft. Each blow stove in a plate, below the water line, as the ship had not the inherent strength to resist.
-- Charles H. Lightoller
Titanic And Other Ships, 1935
Lightoller and Garzke undoubtedly got their Newtonian physics correct. In theory, Titanic could have been so unlucky that it pushed its side against an underwater ram with exactly enough force to crack its steel shell plating, but not enough to throw people out of bed. A single light bump or two against the berg could have accomplished that if the ship came to a stop against the ice in the same manner as a hard landing against a pier when docking. A few light taps seem highly unlikely considering the ship was making more than 22 knots at impact and continued moving throughout the encounter with the ice.
Alternatively, a single hard sideswipe of the iceberg might have caused enough crumpling of the ship's hull to have cushioned the blow. In this impact the bending, twisting and shattering of steel would have produced a single huge hole at the point of contact with no damage anywhere else. Of course, Titanic did not receive damage to only one spot on the bow. Damage extended over a distance of nearly 250 feet from the forepeak all the way into Boiler Room #5. It is the extended nature of this damage that argues most effectively against the "impulse and momentum" type of rebounding impact.
More to the point, the theory of multiple impacts does not fit the experiences described by survivors. Each impulse and rebound would have whipped the deck sideways beneath the feet of passengers and crew. That is not the type of impact anyone reported. The universal description of the accident was a rumbling or vibration, not side-to-side motion of the deck.
Rapid horizontal motion of a deck knocks people off their feet much quicker than large a large roll of the ship. This is because friction keeps the person's feet in place on the deck when it jerks sideways. The victim's torso has inertia which resists sideways movement, with the result that the feet move out from beneath the individual's body. The person's center of gravity is suddenly and unexpectedly no longer supported in a straight line by the legs. A fall is almost inevitable.
If the Lightoller/Garzke horizontal impact took place, an indelible memory of a large percentage of surviving Third Class men who happened to be standing upright in their cabins near the bow would have been an unexpected tumble to the deck. Crew members in their quarters at the very front of the ship would have had the same disquieting experience. Instead, except for one man, they universally recalled only a slight trembling as the ship passed over the ice.
When a ship "strikes the ground," the action can be quite stately. Speed often drops gradually, so gradually that the first moments of a grounding go unnoticed even by professional seamen8. Sliding onto mud or sand may produce almost no sound or vibration. Striking on a hard surface can sound like pouring marbles over sheet metal. Neither type of grounding is the smashing impact of iron against an immovable object. Soft or hard, a grounding is exactly what passengers and crew aboard Titanic experienced during the seven seconds when the ship was in contact with the ice
Author Lawrence Beesley, a teacher on his way to America for holiday, was in Cabin D-56 just aft of the Second Class dining saloon when the ship slid over the ice. His personal experience is a perfect illustration of a ship going aground, not colliding head-on:
...there came what seemed to me nothing more than an extra heave of the engines and a more than usually obvious dancing motion of the mattress on which I sat. Nothing more than that--no sound of a crash or anything else: no sense of shock, no jar that felt like one heavy body meeting another.
-- Lawrence Beesley, The Loss of The S.S. Titanic, Its Story and Its Lessons, Houghton Mifflin, 1912
A grounding such as Beesley described is soft because it does not take place in an instant. Only a small portion of the vessel's displacement weight is involved at the beginning. That increases as the ship slides onto the ground, but this increase is spread over time. The event is not instantaneous like a head-on collision, but takes several seconds from first touch until the ship either stops or breaks free.
Leave a comment
Add a new story to Encyclopedia Titanica
Link and cite this article
Please link to this page using the following URL
Or copy the link text below
If you need to cite this page please copy the following and adapt as necessary for your referencing system:
David G. Brown (2001) The Last Log of the TitanicTitanic Research (ref: #1515, accessed 19th April 2014 10:25:03 AM)
URL : http://www.encyclopedia-titanica.org/last-log-of-the-titanic.html
Added to Encyclopedia Titanica Thursday 28th August 2003, last updated Saturday 19th April 2014.