Ship Log- The analogue recorder is attached to the rotor, this rotor is towed behind the ship. The revolutions of the rotor is carried to a mechanical device called the ‘log register’. The governor is used to keep the rotation of the log line uniform and kink free. Thomas Ferdinand Walker (1837-1921) patented the Cherub Log in 1987 (#4369). The Cherub Mark III series proved to be very successful and was produced between 1930 to 1994.