The Sinking of Titanic

Edward Wilding of H&W presented technical testimony for the inquiries into the sinking in the months after the disaster. He hand calculated how he figured Titanic sank based on the times and water depths reported by survivors. His figures were only small percentages off from modern simulation results and agree nicely with the historical account. The Board of Trade (BOT) inquiry wanted no figures to check, only diagrams.

The actual damage to the ship consisted of a few ruptured seams in the riveted plates along the forward third of the starboard side. The total damage consisted of a hole with an area of 12 sq. feet (1.12 sq meter), but that hole was distributed in the cracks along the forward 6 compartments. This was like pumping water into the ship through a 47 inch (120cm) water main.

The following sums up how Titanic sank and how people perceived the event.

The damage

The first indication for many was a slight lurching in the decks. People in bed noticed the ship did something slightly different from the routine that the last four days had set up in their minds. The ship had grazed the iceberg but not in a smooth sweep. It pushed and bounced off, pushed and bounced, in small bursts, leaving spaced ruptures in the shell plate below the water line. Most people noticed something was different when the vibration of the engines stopped. That was something different in the middle of a voyage.

The perception

It took the first hour (to 12:40am) for the ship to tip down about 5 degrees. That's not going to alarm a lot of people. Over the next 65 minutes (to 1:45am), sinking actually slowed as the bulkhead arrangement controlled the flow of water and time was needed for water to 'permeate' (flow around doors and enter semi-tight spaces) and the ship tipped down only another degree or two. Still no cause for alarm. "Maybe we won't sink before help arrives!"

The ship did not tip down slowly and gradually, but rather in steps. The mass of the ship is very resistant to starts or stops in movement because of inertia. Flooding would cause a loss of buoyancy enough to overcome the inertia and the ship would drop until buoyancy once again over came inertia. In simple terms, early on, people felt a sudden drop of inches near the forward end and the ship didn't seem to move again for a while. Near the final plunge, the ship dropped a couple feet, upwards of a meter at a time, before remaining steady again. During the final plunge, these step wise drops causes waves to run up the decks in an otherwise calm sea.

An analogy for what happened next is to picture slowly pushing a book toward the edge of a table top. The book starts to overhang, no problem. It slowly reaches the balance point and totters a little. One extra little nudge and *FLOP*, over it goes in a heartbeat. That's close to what Titanic did.

Between 1:45 and 2:10, Titanic reached its balance point and tipped another three or so degrees. That might produce concern among a few people.

Between 2:10 and 2:20 it would have gone the full 90 degrees had the ship not broken. I see that as a scenario for mortal terror. *THAT* had to be a *LONG* 10 minutes for the people still aboard. All the lifeboats were away.

Up until about 2am, Titanic was not communicating to those aboard the peril they were in. Things happened very gradually. Around 2am, Titanic's damage stability was compromised and events sped up dramatically. NOW the Titanic was telling the passengers that they were in trouble. Paul Quinn wrote a whole book on what began to happen in "Titanic at Two A.M.: An Illustrated Narrative with Survivor Accounts"

The mechanics of sinking

A ship's design will support a calculated amount of weight before the design is compromised. At that point, the ship will suddenly either tip up or roll over. It doesn't matter where the water enters or what buoyancy is lost. Reach that limit, and the ship goes down. Naval architects will describe this mathematically as the relationship between the center of gravity and the ship's metacenter when discussing a ship's stability.

The forward six compartments were breached in the collision with the iceberg. That includes the cargo holds and the fore boiler rooms #6 and #5. The ship sinks (reaches the limit) when boiler room #4 starts to flood. At 1 am, little water was trickling into #4 as #5 boiler room was still filling. The well deck is slipping under but the forecastle is just above the surface.

#4 boiler room is filling as the bridge approaches the water and the 'big flop' begins. It's 2am.

All water tight doors were reopened from boiler room #4 going aft up until #4 started to flood. On pumping capacity, water was entering at a rate of 15,000 tons per hour, pumping capacity was 1700 tons per hour. During the final plunge, the water tight doors were closed either by the crew (manually) or by the automatic float switches.

Consider also that boiler room's #3, #2, #1 didn't just fill with water. Flooding became increasingly violent, and may have contributed to the break-up.

As the ship tipped to an angle of about 16 degrees, the break-up began. See the break-up page for details on how the ship broke up and left the wreck as we find it today.

The steel used in Titanic

Much has been made of the quality of the steel used on Titanic. The steel used by Harland & Wolff was quality steel for the time. The same steel can be found in the Queen Mary in Long beach (built 20 years after Titanic sank). The sheer and bend qualities of steel used in ships didn't improve until late in WW II when the welded designs of Liberty ships highlighted problems in the quality of the steel. In the final analysis it is wrong to say Titanic was constructed of inferior materials. It's more correct to say that a modern welded design would have better resistance to the kind of collision suffered by Titanic. It should also be noted that if a modern cruise ship suffered similar damage, then all the life boats would be needed. That ship WILL sink. But at least there ARE enough lifeboats for all.

"Lifeboats for all" and other silly phrases

"Lifeboats for all" was the advertising slogan of the shipping industry since the Titanic disaster. If the ship sinks, everyone aboard can be saved, assuming the ship doesn't have a significant list, and there's time to muster the people and launch the boats, and there's enough trained crew members to launch and man the boats, and there's light, and decent weather, and there's no fire, and the severity of the damage is understood in time. Despite the appalling loss of life, Titanic had several "luxuries" for a full blown disaster.

1. The weather was calm. Launching lifeboats in a gale with rain, darkness, and pitching seas becomes problematic and may limit the time available to launch boats. Severe weather may even play a role in why the ship is sinking in the first place.

2. Titanic did not pick up a severe list. The few degrees of list to port and starboard did not significantly interfere with launching all of her boats. Where ships did list heavily before sinking such as the Britannic, Lusitania, Andrea Doria, and most recently the Costa Concordia, half of their lifeboat capacity on the high side became unusable.

3. Titanic had an hour and a half of usable time to get 18 of her 20 boats properly launched. Had the ship flooded faster, fewer boats would have been launched. If Titanic had the full 32 or 64 boats her davits were designed to handle, there wouldn't have been enough time to load them and get them off safely.

4. Titanic had adequate trained crew to get off the 16-20 boats with which Olympic class ships were equipped.

5. Only the seamen (of which 44 were hired for Olympic class ships) in the crew were trained in operating a gadget like the Wellin Lifeboat davits or manning a small craft at sea. The "Black Gang" (comprised of boiler stokers and coal handlers) and the Victilating Crew (composed of stewards, butchers and bakers) where hired on ships by the voyage and they were not expected or trained to do tasks associated with lifeboats. Space was set aside in the ship's design for 44 seamen. In addition, two seamen were initially lowered with each boat to ensure there was someone on the boat who knew anything about manning boats on the ocean. That was quickly cut to one per boat because the officers were quickly running out of men to man the boat handling gear. Increasing the number of boats would mean increasing the number of seamen aboard. That costs money. Additional paying quarters would have to be converted to house them. That costs more money. What do you do with all the extra seamen if there's no disaster? On all the ships that had "lifeboats for all", none hired additional crew to handle them.

6. There was no fire. That would have pulled additional seamen away from lifeboat duty. Nobody else knew where the water hydrants were. Again, other crew were not trained in shipboard fire fighting and using the gear aboard. Training costs money.

7. The lights didn't go out until the end. Without power, only those spaces close to windows would have any light at all. At night, the entire ship is as dark as a tomb. A weak point in the design of the Olympic class ships was that the main dynamos and emergency generators were steam powered. If a collision or other disaster event severed the steam lines from the boiler rooms up forward from the generators aft of the main engine rooms, the lights would be lost (included the dim emergency lights at the exits). Titanic's power plants were supplied with steam from boiler rooms 2 and 3, or from boiler room 1 while in port. Damage to the engine room could cut steam power to both the generators and the pumps. Those boiler rooms were the last to flood and were not an issue. Modern ships are also susceptible to scenarios where power is cut and electric pumps and boat handling gear are rendered useless.

8. Tom Andrews was aboard. This may have been the most important luxury. Tom Andrews was the primary designer of the Titanic. He was aboard to oversee the maiden voyage and head a crew from H&W seeing to last minute details. Because he had total knowledge of the damage stability properties of the ship, he was able to quickly determine the severity of the damage and do a few back-of-the-envelope calculations. He communicated to Capt. Smith in no uncertain terms that the ship would sink and roughly when. Even seasoned sea captains are not always schooled in the naval architecture of their ships. It's possible that the captain may have waited too long until he was sure there was a serious problem before launching lifeboats, resulting in greater loss of life.

Potential problems such as these are still with us today, but don't worry. The are lifeboats for all, thanks to the Titanic disaster. Have a nice cruise!

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Copyright 1997 and 2012 Roy Mengot