Anschütz gyrocompass

What it is

A gyrocompass indicates true geographic north rather than magnetic north, and is unaffected by the steel of a ship's hull or by electrical equipment. Hermann Anschütz-Kaempfe filed his first patent on a gyroscope apparatus for ships in 1904, founded Anschütz and Co. in Kiel in 1905, and had a production-ready compass tested on the battleship SMS Deutschland in 1908.

How it works

A rapidly spinning rotor resists changes in the direction of its axis. Suspended so that gravity acts on it, the gyroscope is gently pulled by the Earth's rotation until its axis settles in the north south meridian. Damping stops it swinging back and forth around north. Anschütz's cousin Max Schuler worked out the mathematics of these oscillations; the Schuler period of about 84 minutes, the swing of a pendulum as long as the Earth's radius, is still fundamental to inertial navigation.

Why it stands out

• In 1913 the HAPAG liner Imperator became the first commercial ship fitted with an Anschütz gyrocompass.
• When Anschütz sued the American Elmer Sperry for infringement, Albert Einstein served in 1915 as the expert, and the court found for Anschütz.
• Einstein later contributed to the two-gyrosphere compass, produced from the mid-1920s, and received one per cent of the sale price of each unit. Sources give 1922 or 1926 for the royalty agreement.
• Einstein spent many summers sailing on the Kiel Fjord with Anschütz-Kaempfe.

Where you meet it

In 1920 Anschütz paired the compass with its first ship autopilot, nicknamed the iron helmsman, and the combination of gyro and automatic steering remains standard. On the bridge of merchant ships, naval vessels and superyachts, where gyrocompasses feed autopilots, radar and electronic charts. Anschütz in Kiel still makes them, now as part of integrated bridge systems, and returned to German ownership in 2023.

Sources

• Anschütz: Company history
• heise online: The Schuler period
• Yacht: Albert Einstein relaxed by sailing
• Wikipedia: Anschütz GmbH