There's not much in the
way of interesting scientific anniversaries on my list for this month,
which suits me fine, because it means I can focus on the one that
interests me most: the 40th anniversary of the launch of the world's
first nuclear submarine, the USS Nautilus, on January 21, 1954.
I don't know why, but
submarines have always fascinated me. Maybe it's because I've lived my
whole life on the prairies, as far as you can get from an ocean, which
lends the sheen of the exotic to anything to do with the seas. Maybe it's
from early exposure to the old television series Voyage to the Bottom
of the Sea (recently reincarnated, for all intents an purposes, as
Sea Quest DSV) and Jules Verne's novel 20,000 Leagues Beneath the
Sea. Whatever, the 40th anniversary of the launching of the Nautilus
seems an excellent opportunity to pursue my submarine interest.
Submarines have been
around a surprisingly long time. Cornelius Drebbel, court engineer to
James I of England, demonstrated an underwater vessel on the Thames way
back in 1620. It was propelled by oars sealed at the locks by leather
gaskets, and submerged (as far as we can tell) by letting water into the
hull, then surfaced by pumping it out again (and crewed, one hopes, by
volunteers!).
That's still the way
submarines do it today, although with greater sophistication. Submarines
consists of two hulls, an inner one containing air, called the pressure
hull, and an outer one. The space between the two is filled with ballast
tanks, which are flooded with water to make the sub sink and pumped full
of air to make the sub rise.
A submarine is thus a
perfect example of Archimedes' Principle, which states that an object in a
fluid will rise if the amount of fluid it displaces weighs more than it
does, and sink if the amount of fluid it displaces weighs less than it
does. It stabilizes at a point at which the amount of fluid it displaces
weighs exactly the same as it does. Submarines control their depth by
matching their weight to the weight of the water they displace
The second submarine of
note, the Turtle, added another innovation: propellers. Designed
by David Bushnell while he was a student at Yale (those crazy engineering
students!) and launched during the American Revolution, it was a one-man
craft shaped sort of like a fat barrel. A complex system of valves, air
vents and pumps controlled its rising and sinking, and propulsion came
from two sets of hand- and foot-cranked propellers: one set to drive it
forward and one to move it up and down. On September 6, 1776, Sgt. Ezra
Lee piloted the Turtle out to the British flagship Eagle off
New York and attempted to attach a mine to it with an auger.
Unfortunately (or fortunately, depending where your sympathies lie), the
auger couldn't penetrate the Eagle's copper sheathing. Lee
jettisoned the mine and no damage was done.
The nuclear Nautilus
was named that for a good reason: the first practical submarine was also
named Nautilus. Robert Fulton (of steamboat fame) demonstrated it
to the French navy in 1800 and 1801. Compared to the crude Turtle
of just 25 years before, it was a modern marvel. Made of metal, it
carried four men, could stay underwater for six hours, had a streamlined
fish shape to reduce water resistance, used water ballast tanks to raise
or lower the craft, and was propeller-driven--although, there being no
practical underwater power source yet, the propeller, like the Turtle's,
had to be cranked by hand. However, for surface travel, it carried a
collapsible mast and sail.
The Nautilus
added one more important innovation: horizontal rudders, or diving
planes, to control the angle of the sub's ascent or descent. With that
addition, the elements of the modern submarine were all present. However,
none of the governments Fulton demonstrated the Nautilus for were
convinced, and so he dropped the project.
The Nautilus was
designed to tow a mine that could be brushed up against an enemy ship:
from the beginning, submarines have been seen primarily as military
vessels. To the Confederates in the U.S. Civil War went the dubious honor
of being the first to actually sink a ship via submarine: the
hand-cranked sub Hunley carried a "spar torpedo"--an explosive
charge on the end of a six-metre pole. It succeeded in sinking the USS
Housatonic off Charleston on February 17, 1864, but destroyed itself
in the process.
World Wars I and II
brought fleets of more-and-more-advanced submarines into the world's
oceans. Electric motors finally provided a suitable underwater power
source, although batteries had to be recharged frequently by extended
surface travel using diesel engines. That's why submarines of the two
world wars still had the shape of surface vessels, with sharp prows and
long, slender hulls.
The nuclear Nautilus
had those features, too, because that's how the U.S. Navy knew how to
build submarines: but the nuclear Nautilus spelled the end of the
days of extensive surface running.
A nuclear-powered sub
contains a small, well-shielded nuclear reactor that creates intense heat,
which is used to generate steam to turn propulsion turbines and supply
electricity for all the subsidiary systems. Because nuclear power does
not require oxygen and produces no noxious fumes, it puts no strain on the
submarines' air supply. In fact, it powers devices which turn seawater
into fresh water and oxygen.
That means that a
nuclear submarine's range is practically limitless. The Nautilus
sailed 170,000 kilometres, 146,000 of them submerged, before refueling,
and on August 3, 1958, even sailed under the Arctic ice and the North
Pole. In 1960, a second-generation nuclear sub, the USS Triton,
sailed around the world, entirely underwater, in just 84 days.
Without the need for
frequent surface running, modern nuclear submarines have teardrop-shaped
hulls that provide the maximum streamlining for underwater travel: and
allow speeds of up to 30 knots, fast even for most surface ships.
The Nautilus
pointed the way, for good or bad, to today's world where fleets of
submarines carrying enough nuclear missiles to destroy entire countries
are continually at sea, but with its trip under the Arctic ice, it also
showed how submarines could be used for scientific research.
Here's hoping the future
focus is on submarines more for the latter purpose than the former.
