Gyrocompass

The invention: The first practical navigational device that enabled
ships and submarines to stay on course without relying on the
earth’s unreliable magnetic poles.
The people behind the invention:
Hermann Anschütz-Kaempfe (1872-1931), a German inventor
and manufacturer
Jean-Bernard-Léon Foucault (1819-1868), a French experimental
physicist and inventor
Elmer Ambrose Sperry (1860-1930), an American engineer and
inventor
From Toys to Tools
A gyroscope consists of a rapidly spinning wheel mounted in a
frame that enables the wheel to tilt freely in any direction. The
amount of momentum allows the wheel to maintain its “attitude”
even when the whole device is turned or rotated.
These devices have been used to solve problems arising in such
areas as sailing and navigation. For example, a gyroscope aboard a
ship maintains its orientation even while the ship is rolling. Among
other things, this allows the extent of the roll to be measured accurately.
Moreover, the spin axis of a free gyroscope can be adjusted to
point toward true north. It will (with some exceptions) stay that
way despite changes in the direction of a vehicle in which it is
mounted. Gyroscopic effects were employed in the design of various
objects long before the theory behind them was formally
known. A classic example is a child’s top, which balances, seemingly
in defiance of gravity, as long as it continues to spin. Boomerangs
and flying disks derive stability and accuracy from the spin
imparted by the thrower. Likewise, the accuracy of rifles improved
when barrels were manufactured with internal spiral grooves that
caused the emerging bullet to spin.
In 1852, the French inventor Jean-Bernard-Léon Foucault built
the first gyroscope, a measuring device consisting of a rapidly spinning
wheel mounted within concentric rings that allowed the wheel to move freely about two axes. This device, like the Foucault pendulum,
was used to demonstrate the rotation of the earth around its
axis, since the spinning wheel, which is not fixed, retains its orientation
in space while the earth turns under it. The gyroscope had a related
interesting property: As it continued to spin, the force of the
earth’s rotation caused its axis to rotate gradually until it was oriented
parallel to the earth’s axis, that is, in a north-south direction. It
is this property that enables the gyroscope to be used as a compass.
When Magnets Fail
In 1904, Hermann Anschütz-Kaempfe, a German manufacturer
working in the Kiel shipyards, became interested in the navigation
problems of submarines used in exploration under the polar ice cap.
By 1905, efficient working submarines were a reality, and it was evident
to all major naval powers that submarines would play an increasingly
important role in naval strategy.
Submarine navigation posed problems, however, that could not
be solved by instruments designed for surface vessels. Asubmarine
needs to orient itself under water in three dimensions; it has no automatic
horizon with respect to which it can level itself. Navigation
by means of stars or landmarks is impossible when the submarine is
submerged. Furthermore, in an enclosed metal hull containing machinery
run by electricity, a magnetic compass is worthless. To a
lesser extent, increasing use of metal, massive moving parts, and
electrical equipment had also rendered the magnetic compass unreliable
in conventional surface battleships.
It made sense for Anschütz-Kaempfe to use the gyroscopic effect
to design an instrument that would enable a ship to maintain its
course while under water. Yet producing such a device would not be
easy. First, it needed to be suspended in such a way that it was free to
turn in any direction with as little mechanical resistance as possible.
At the same time, it had to be able to resist the inevitable pitching and
rolling of a vessel at sea. Finally, a continuous power supply was required
to keep the gyroscopic wheels spinning at high speed.
The original Anschütz-Kaempfe gyrocompass consisted of a pair
of spinning wheels driven by an electric motor. The device was connected
to a compass card visible to the ship’s navigator. Motor, gyroscope, and suspension system were mounted in a frame that allowed
the apparatus to remain stable despite the pitch and roll of the ship.
In 1906, the German navy installed a prototype of the Anschütz-
Kaempfe gyrocompass on the battleship Undine and subjected it to
exhaustive tests under simulated battle conditions, sailing the ship
under forced draft and suddenly reversing the engines, changing the
position of heavy turrets and other mechanisms, and firing heavy
guns. In conditions under which a magnetic compass would have
been worthless, the gyrocompass proved a satisfactory navigational
tool, and the results were impressive enough to convince the German
navy to undertake installation of gyrocompasses in submarines and
heavy battleships, including the battleship Deutschland.
Elmer Ambrose Sperry, a New York inventor intimately associated
with pioneer electrical development, was independently working on a design for a gyroscopic compass at about the same time.
In 1907, he patented a gyrocompass consisting of a single rotor
mounted within two concentric shells, suspended by fine piano
wire from a frame mounted on gimbals. The rotor of the Sperry
compass operated in a vacuum, which enabled it to rotate more
rapidly. The Sperry gyrocompass was in use on larger American
battleships and submarines on the eve ofWorldWar I (1914-1918).
Impact
The ability to navigate submerged submarines was of critical
strategic importance in World War I. Initially, the German navy
had an advantage both in the number of submarines at its disposal
and in their design and maneuverability. The German U-boat fleet
declared all-out war on Allied shipping, and, although their efforts
to blockade England and France were ultimately unsuccessful, the
tremendous toll they inflicted helped maintain the German position
and prolong the war. To a submarine fleet operating throughout
the Atlantic and in the Caribbean, as well as in near-shore European
waters, effective long-distance navigation was critical.
Gyrocompasses were standard equipment on submarines and
battleships and, increasingly, on larger commercial vessels during
World War I, World War II (1939-1945), and the period between the
wars. The devices also found their way into aircraft, rockets, and
guided missiles. Although the compasses were made more accurate
and easier to use, the fundamental design differed little from that invented
by Anschütz-Kaempfe.