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 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.
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.
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.
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 25,000 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.
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. 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.
The problem doesn't lie with the steel used in the hull plates, but rather in riveted construction. Two problems arise. First, if a collision bends a hull plate, then a 90 degree sheer is applied to the rivets. The rivets have the same properties as the hull steel and perform poorly under sheer pressure. Secondly, the holes in the hull plates for the rivets are 'cold stamped'. The holes are punched out by a stamping machine and it leaves micro-cracks in the plate around the hole that might give way in a stress situation.
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. The weakness was the riveted construction of the time. 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.
Copyright 1997 Roy Mengot