Last night, someone posted this video animation of Titanic sinking in real time:

Yes, I watched it. The full two hours and 45 minutes, because I am that kind of geek. It was a little disturbing to see the ship completely devoid of people, its lifeboats magically launching by themselves, but it was also fascinating to watch just how fast the ship’s final moments (where it broke in two) progressed.

But for me, the hypnotic part occurred in the first 20 minutes or so, when the ship resumed moving at half speed, and the sound of the engines was reproduced.

Ah, Titanic engine porn.  There was no part of James Cameron’s movie that grabbed me more than those tantalizing glimpses of the engine room early in the movie.  The Titanic was a triple-screw liner (meaning it had three propellers).  One of these, the central one, was driven by a low-pressure Parsons turbine.  It’s the other two that most intrigue me – a pair of massive four-cylinder triple-expansion reciprocating steam engines.  Now, I’m not really an engine geek. I do understand the basics of what happens with these engines, where steam (produced by the 29 coal-fired boilers containing a total of 159 furnaces, and then collected through spider-like intakes)  enters under high pressure, which drives one piston, then on to a medium-pressure-driven piston and then finally to two low-pressure ones, which drive the shafts of the propellers.  “Reciprocating” refers to the up and down motion of the piston within a cylinder. This video explains how that all worked, with some fabulous animation of the whole process:

The mechanics are cool (especially since they help you understand what you’re hearing when the engine runs–more on that in a moment), but what fascinates me is the size and the music of those engines.

The Titanic‘s two reciprocating engines were 30′ tall, 63’ long, and weighed 720 tons; add their bedplates and each weighed close to 1000 tons.

No photographs of the completed engine room survive, but these two screen grabs from Cameron’s Titanic give some sense of what it must have looked like:

These engines were located just aft of the middle of the ship, immediately adjacent to where the ship fractured in two before sinking.   They sank with the rest of the stern in a chaotic, twisting motion, slamming hard into the ocean floor.  Their size may have allowed them to survive in recognizable form in a part of the ship where so much of the wreckage is twisted almost beyond recognition.   Here’s the stern section:

Note the engines clearly showing right at the break point.  Here’s a closer view:

Here’s a fascinating scratch-built model of the stern (really good view of the engines right around the 3 minute mark):

But on to the sound.  I’ve heard steam engines before (in fact, I rode on a train powered by a steam engine just today), but never ones on the scale of the giants that powered Titanic.  Several people have posted video/sound links replicating what those engines must have sounded like, based on audio files of an extant large steam engine.  To get the full effect of this sound, I recommend either headphones or a really, really loud sound system.

That 4/4 rhythm produced by the four cylinders is absolutely hypnotic.  The deeper boom on the first “beat” is the high-pressure cylinder.

This was the heartbeat of the ship, and when it stopped for the last time, two hours before Titanic sank beneath the icy Atlantic, it presaged the end of over 1500 individual heartbeats that would come.

If you’d like to listen to this on a 10 hour loop, here you go. You’re welcome.