The Titanic saga is well-worn and it has
been told a million times - if you’ve ever watched a documentary on the ship you’ve
probably heard metaphors about icecube trays overflowing and heard all about watertight
doors, compartments, rivets and all that. But what does it all mean? Why wasn’t
Titanic designed to withstand the iceberg? What exactly caused the ship to sink so quickly?
How can ice damage steel? Well today let’s take a close look at all this and more and find
out just how the iceberg sank the Titanic. To answer this question we have to look at
the events in four steps; first, the ship’s design. Second, the events. Third; the damage
and fourth, the aftermath. Let’s get started. First some quick context. Titanic was designed
and built by an incredibly experienced team of engineers, builders and artisans and even
though heralded as the world’s largest ship - at the time - the Titanic was actually built in an
almost identical manner to hundreds and hundreds of other ships. You see, Harland and Wolff -
the shipbuilding firm in Belfast - had been building ships since 1861 and they were pretty
damn good at it. In fact they were up there as one of the best shipbuilding firms in the world.
They were the builders of choice, not just for Titanic’s owners the White Star Line, but dozens
of other shipping lines like P&O, Union Castle, Furness Bermuda, Royal Mail and many more. But
a long-standing agreement saw White Star Line commissioning virtually every one of their ships
to be built by Harland and Wolff. One of the many stupid myths about the Titanic disaster is that
Harland and Wolff was a cost-cutting organisation and built their ships out of sub-standard
materials. It’s just not true. They’d been doing this for a long, long time and knew their stuff;
and they were extremely proud of their product. So when White Star Line began discussing plans
for a trio of super-liners early in about 1907 or 1908, Harland and Wolff was all
ears. They knew they’d have to overhaul their entire shipyard to accommodate the
massive engineering task so they knocked down all their old slipways and built a monstrous
gantry to support cranes and build the new ships as well as a cavernous graving dock to fit the
ship out once it was afloat- oh look there’s me! The reason I’m telling you all is this because
I want to try to highlight something for you; Titanic, and her two sisters Olympic and
Britannic, were not really that special. Yes; they were big. Really big for the
time. But Harland and Wolff wasn’t going to re-invent the wheel on this project. They
took what they had built on a smaller scale; ships like White Star’s Oceanic, Laurentic
and Adriatic - and scaled the designs way up. So if you can understand how Olympic
and Titanic were built - then you really know how almost every Harland and Wolff ship
was built in the lead-up to the 1920s. So when White Star began talking about advanced
safety features for the new ships Harland and Wolff was happy to oblige because up until only
relatively recently by then, travel at sea was a bit of a gamble - fairly regularly ships
were lost in storms and just never showed up. White Star Line cut its teeth on the run to
Australia - that was a particularly dangerous route and the worst 19th century loss of
life in Australian waters happened after 4 months at sea when the ship was just one
day away from docking safely in Melbourne. So the travelling public was a bit apprehensive
about travel at sea. It didn’t help that in 1909 White Star lost a ship, the Republic,
when it was rammed and sunk off Nantucket. White Star and Harland and Wolff would go above
and beyond to make Olympic and Titanic as safe as possible - safer really than any other ship
afloat - and then market the hell out of it. So - what does this all have to do with the
design? Well, let’s look at how Titanic was built from the ground up. Titanic’s hull was
a giant box girder; if you can picture it that way then all the individual components will make
sense. Box girders are immensely strong and they are ideal for resisting torsion, or twisting,
which is very useful in ships because they are very long and prone to flexing and
twisting while going over big waves. Box Girders require four “walls” to function. In
Titanic’s case, the bottom wall was the keel, the top wall the strength deck and the two side walls
the hull. Here’s how it was built. First, the keel was laid - this is essentially the ship’s backbone
- it comprised a keel plate which sat flat on the slipway’s blocks - and then a girder which ran
most of the length of the ship. Then along the length of the keel were fitted these things called
‘floors’ - they provided the something for more longitudinal girders to be riveted to - and slowly
the width of the structure increased until you had an immensely strong steel skeleton. The bottom of
this was plated. The steel plates basically formed a watertight skin for the ship. They were made
of steel and were surprisingly thin; on Titanic the plates ranged from .64 of an inch - 1.6cm - to
about 1.25 inches or 3cm. The bottom of Titanic, under the keel, was where the heaviest plates were
used - those 1.25inch plates I just mentioned. Now on earlier ships this is kind of where the
yard would move on to the next step, but by Titanic’s day things had developed a bit and the
ship was given a ‘double bottom’. This basically involved riveting a second watertight skin of
plates on top of the keel structure. The ‘deck’ this created was called the Tank Top, and for good
reason, because the space in between the plates on the bottom of the keel and the plates on top oat
the tank top was subdivided into tanks for ballast water. The reasoning for this simple; ships for
as long as they had existed, had been bumping into things. So there was a lot of knowledge around
the kind of damage a ship was likely to encounter. Grounding damage was some of the worst - in fact,
Costa Concordia fell victim to this in 2012. If Titanic encountered shallow rocks or
something they could pierce the bottom plating and open the ship’s hull up to the ocean, sinking
it quickly. The second layer of plating on the tank top would prevent this from happening.
Crucially though; the second row of plating ended there. It did not continue up the sides of
Titanic’s hull. But we’ll get to that in a minute. Next, to the floors were riveted giant
frames which began to form the hull, the side floors of the box girder - these were
forged steel beasts multiple storeys tall, bent into the correct shape to give Titanic’s hull
it’s streamline hydrodynamic form - and they ran the length of Titanic’s hull spaced out every 24
to 33 inches depending on their location. To these frames were riveted the majority of Titanic’s hull
plates; basically the external skin of the ship. From here up, the plates which weren’t part of the
double bottom were a little bit thinner. This was to save a bit of weight and give the ship greater
flexibility while rocking and rolling through a storm. Each plate had rows of rivets hand-driven
into each edge. The rivets were wrought iron, pushed red-hot in place and then hammered home
until they fastened two plates together. 3 million were used to construct Titanic’s hull and every
single plate edge was dotted with dozens of them. If you were standing in Titanic’s boiler or
engine room, way down at the bottom of the ship, you’d be standing on top of the tank top. Looking
to the side you’d see big frames just where they curve to join the keel and its floors - and you’d
see plates. There is nothing between those plates and the ocean on the other side. There’s not a
second layer or inner skin or anything like that. Finally to give the box girder it’s roof the
reinforced strength deck, which on Titanic sat at B-Deck, was riveted into place
and all the subsequent decks below it. Remember when I called Titanic’s hull a box
girder? Here’s an actual box girder design, a cross section of the tubular
Britannia bridge. Looks familiar, right? Okay - so Harland and Wolff have the hulk of a
ship. At the moment it’s safe from damage to the bottom in, say, a grounding. But what if the ship
is hit from the side? An impact from a collision would mean water could flood the hull and sink the
ship in minutes. No, something had to be done to prevent this. It seems incredible that the idea of
watertight compartments was kind of revolutionary; for hundreds of years ships had
just sailed around without them. Titanic took the idea to the next level. Titanic’s
hull was divided into 16 compartments - basically massive self-contained rooms, by 15 bulkheads
which were basically heavy-duty steel walls that ran up the hull as high as practicable.
These were made of steel plating and, of course, ran through some passenger and crew areas in the
lower decks. This meant that to get through them there had to be some kind of doorway fitted that
could be sealed up in the case of an emergency. On Titanic, this came in the form of the watertight
door and Titanic had a couple of different types. First is probably the most famous; seen here
dramatically closing in the 1997 movie Titanic. These ran on rails and closed downwards. They
were made of heavy cast iron and in the boiler and engines rooms had to be wide enough for men to
pass through with coal-carrying wheelbarrows. The doors were held open by a clutch; this could be
released automatically by switches in the bridge or individually by simply lifting a
hand-lever connected to the clutch. Each door could also be closed manually by
hand-cranking it shut from the deck above. One final safeguard was installed; in the event
of flooding, a float would raise the lever and disengage the clutch, lowering the door.
The doors were designed to lower slowly at first so men could get out of the way, but for the
last 18 or 24 inches would drop suddenly like a guillotine to create a watertight seal.
This guy would have been in big trouble. The second kind of watertight door closed
horizontally, or laterally and these were the ones found in most of the passenger
and crew areas on Titanic’s lower decks. These had to be hand-cranked shut
either on-site or from the deck above. The watertight bulkheads had as few openings
as possible and, when the doors were shut, created a compartment with four watertight
surfaces; the tank top, the hull sides and the two watertight bulkheads. However; there was no top
watertight surface. The decks above weren’t made watertight because the bulkheads rose fairly high
up in Titanic’s hull above the normal waterline up here on E-Deck. With this system in place, Titanic
could survive a number of theoretical disasters. If hit by another ship from the side, two or
three of Titanic’s compartments would flood; but the ship could float because the water
could flood only about as high as the top of the watertight bulkheads. If the ship received
damage to the first three or even four of her compartments, say in a side-swipe collision or
impact - then the water also could not flood any higher than E Deck before the ship found
equilibrium, the flooding would stop, and the ship would survive - although it’s bow would be
pretty low down in the water. Basically, Titanic was designed to withstand any and all of the kind
of damage any ship had experienced up until that point. Bow-on collisions, groundings, impacts from
other ships; Titanic could survive them all. She was almost… what’s a good word here - unsinkable?
Unsinkable. That’s a good one, let’s use that. Part 2 - the events.
Just before midnight on April 14th, 1912 Titanic’s lookouts and bridge spotted an
iceberg ahead at around about the same time. The ship only had seconds to react and it was just
too late; instead of striking head-on directly, Titanic’s rudder had moved the nose of the ship
away from the iceberg by a few degrees so the berg scraped past along the side. Rushing
to the bridge from his adjoining stateroom, Titanic’s captain Edward Smith now had to diagnose
his ship and gauge exactly what the situation was. He ordered the watertight doors closed but First
Officer William Murdoch reported he had already thrown the switches, so the vertical-closing doors
down in the boiler and engine rooms were shut. Then he ordered the ship’s 4th Officer, Joseph
Boxhall to go below and check for damage and eventually the ship’s carpenter. Already
Titanic was exhibiting some strange symptoms; one of the ship’s lamp trimmers walked up on deck
at the very bow of the ship because he could hear a hissing noise. Up at the forepeak of the ship,
the very front, was a vent for one of the ship’s tanks; the peak tank. This was the forwardmost
tank on the ship and in order to be able to trim the level of the ship and keep it on an even keel,
it could be filled or emptied of seawater. The air had to be displaced, so the vent allowed air
to escape out. But now it was loudly hissing, indicating that the forepeak tank was
taking on water at an alarming rate. Just aft of this area, in the cargo hold,
Boatswain’s Mate Albert Haines was investigating for damage and he could hear water rushing
in; the number 1 cargo hatch ran down into the belly of the ship and at certain levels was
covered with tarpaulins or grates. He found that the tarpaulin was being pushed up by air as it
escaped upwards, displaced by the water. This was all reported to the bridge; to Smith this meant
that two watertight compartments were already opened to the ocean and flooding. Then there came
more bad news; boiler room 6 was flooding rapidly; so rapidly, the crew had had to escape up
emergency ladders to get out of the way of water. That made at least 2 compartments flooding; then
came news from the post office. This was located up on G-deck and had a mail sorting room just one
deck below on the Orlop Deck. Ten minutes after the collision, water began to flood the mail
sorting room on the Orlop Deck and the clerks began to shift mail as fast as they could to save
it. This mail room was located in the watertight compartment forward of boiler room number 6;
that made four compartments open to the ocean. Finally, Smith went below to check the damage
for himself; cargo holds 1,2 and 3 were flooding. Boiler room 5 had a small hole and it was flooding
too, just slower. About 20 minutes after the collision, the Squash Racquet court was reported
to be flooding. It painted a disturbing picture for Titanic’s commander and officers;
the forepeak tank taking on water; cargo holds 1 and flooding rapidly, cargo hold 3
flooded and water now lapping in the Squash court, boiler room 6 flooded and boiler room 5 taking
on water. This spelt the end for Titanic; the ship was designed to stay afloat with
four of those compartments flooded. But now, with the bow of the ship being pulled down by the
weight of water in five compartments, it was past the tipping point and water would surge up over
the bulkheads because of course the top of the compartments were not watertight. And this it
did; by about 12.45 am, around an hour after the collision, Steward Joseph Wheat found water
pouring down the E-Deck steps which led down to the Turkish Bath one deck below. This meant that
water was coming up over the watertight bulkhead separating the damaged boiler room 5 from boiler
room 4 below and flooding aft into the ship. 3. The Damage
So what happened to cause this kind of wide-spread flooding? I mentioned earlier
that Titanic didn’t hit the iceberg head-on and that it managed to turn a couple of points and
get it’s nose out of the way of the iceberg ahead. This meant that Titanic’s side brushed up against
the iceberg and suddenly the ship’s entire 40 or 50,000 ton mass was grinding up along the ice.
That ice, by the way, is extremely compact glacial ice; very dense stuff. By contrast, Titanic was
- well - a bit squishy. Steel bends quite a bit under pressure. If you look at photos of Titanic’s
sister ship Olympic after a 1911 collision, you can see the steel plating bent like wet
cardboard and rivets popped out of place. The rivets on Titanic was immensely strong but when
the ship came into contact with the iceberg a huge amount of pressure was put on them and they likely
burst in some sections allowing the hull’s plates to open up ever so slightly and allow water in.
It wasn’t a dramatic tear hundreds of feet long; if that was the case, Titanic would have
sunk in minutes and not over two hours. No, it was a series of small cuts in the hull plating
and thanks to sonar imagery and the damage reports from the night, we have a good idea of where
they were. The first cut probably appeared here, in the region of the forepeak tank. This
caused the hissing noise that could be heard as it flooded with water. Next, a 5 and 6 foot
gash were both put into Cargo Hold number 1. Then the seam of plates in cargo
hold 2 opened up for about 16 feet. Just after this, between cargo holds 2 and 3, a
33 foot gash opened up Titanic’s fourth watertight compartment - and finally just aft of this, a
big 45 foot incision opened up Boiler Room 6 and a little bit of Boiler Room 5. The
plates could only have been separated by about as little as a half inch to 6 inches
but these openings were enough to doom Titanic. 4. The Aftermath
The immediate shock and outrage caused by the disaster initiated wide-sweeping changes
to the way ships were designed and built for the next few decades. The most obvious solution was to
install a second ‘inner skin’ to the hull - like the double-bottom but running up the height of
the boiler and engine rooms. This modification was made to Olympic and was built into Britannic, the
third sister ship. Then the watertight bulkheads were raised higher; on Olympic, these went as
high as B-Deck - the strength deck - but it also meant now, in public spaces, there had to be
installed the horizontal-closing watertight doors. After the disaster, the general consensus somehow
became that a 300-foot long gash in the Titanic’s hull had been ripped open by the iceberg but this
just wasn’t possible because such extreme damage would have sent Titanic to the bottom way faster.
It was Edward Wilding who first postulated that the ship’s damage had been intermittent; “I cannot
believe that the wound was absolutely continuous the whole way. I believe that it was in a series
of steps, and that it was the end of one of these series of wounds which flooded the different
spaces." - referring to boiler rooms 5 and 6. In 1986 Wilding may have been proved correct;
Dr Robert Ballard observed what little could be seen of the area that made contact
with the iceberg and found plate damage; a 45 foot long opening about 1 to 6 inches wide
in the seams of the plates. This was the one that directly opened up boiler room 6 and part of
boiler room 5 - the incision that doomed Titanic.
