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PROFESSOR: When we
take complex things

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and break them into
smaller pieces,

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we find out that we know
a lot more about things

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than we think.

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[MUSIC PLAYING]

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Now let's take this box
ORCA I and can create damage

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below the water line, which
I've indicated right here.

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[MUSIC PLAYING]

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Now let's put ORCA I in the
water and see what happens.

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[MUSIC PLAYING]

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[WATER FLOWING]

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[FOG HORN]

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The ORCA I sank due to the
weight of the added water.

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What if the ORCA I contained
cargo or oil or even people?

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Now let's take ORCA II
and do the same thing.

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[MUSIC PLAYING]

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[WATER FLOWING]

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[BELL RINGING]

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So we can see that
ORCA II did not sink,

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although it is sitting at
an angle towards the bow.

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So why didn't ORCA II sink?

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As easy as it sounds,
this simple demonstration

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is essential to design
a huge, complex ships.

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Ships that are responsible
for carrying about 90%

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of all our stuff.

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As Naval architects,
how do we design

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ships carrying our stuff to
make it into port safely and not

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sink?

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[MUSIC PLAYING]

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Here have ORCA I and
ORCA II from before.

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Although ORCA I
and ORCA II don't

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engage in international
trade, they

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behave just as a 1,000
foot container ship would.

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Now let's take a look in ORCA
I. We can see that there's

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nothing in it, it's just a box.

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But if we look at
ORCA II, we can

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see that it's subdivided into
these watertight compartments

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by these transverse
water type bulkheads.

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Now what that
means is that if we

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were to damage the
ship right here,

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water would only flow
into this compartment.

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It would not going to this
one, this one, or this one.

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That would cause the ship to be
angled or trimmed in the water,

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but it would not cause the
ship to sink completely.

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We refer to ORCA II
as being subdivided.

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And we can see subdivision in
many of these ships' plans.

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It Is unclear when
subdivision first

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started being used in ships.

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But accounts of 5th
century Chinese trade ships

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indicate that water
would be able to enter

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the vessel without sinking.

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So let's find out
why this happens.

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Let's imagine a barge divided
into 10 equal compartments.

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One of them springs
a leak from damage.

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Since the ship is subdivided,
only the first compartment

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floods and the ship
remains afloat,

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protecting both its
people and cargo.

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Although the added water
causes the ship to trim,

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it still has enough buoyancy
to return to port for repairs.

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[MUSIC PLAYING]

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Ships still sink though.

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It's both expensive
and impractical

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to try to design
the unsinkable ship,

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especially when these
ships will never

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see that amount of damage.

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That's why as
naval architects we

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use computer programs to
help us out with subdivision.

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Computers make it easy to
simulate certain damage

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cases in practically no time.

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With different software, we
can damage certain compartments

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and see how the
ship responds to it.

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This gives a naval
architect a good idea

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of what parts to improve
on the ship, if any.

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So even though ships seem
like these intricate, complex

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things, they're really
just based on principles

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that we all already know.

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[MUSIC PLAYING]