AUTOMATIC STEERING. 
By Eimer A. Sperry, E. D., MEMBER. 
[Read at the thirtieth general meeting of the Society of Naval Architects and Marine Engineers, held in 
New York, November 8 and 9, 1922.] 
The dearth of accurate knowledge with reference to the steering of ships is nothing 
short of amazing. A search of the literature in this and closely associated arts fails to 
reveal anything but the most meager reference to this important phase of ship operation. 
Doubtless the very great difference in the behavior of ships and their response to helm 
under efforts to keep them on their course under conditions which to all intents and purposes 
seem identical indicates the impossibility of laying down any set rules and regulations look- 
ing towards standard performance. This certainly stands in the greatest contrast to the 
amount of literature available on the propulsion plant, propellers, stream line forms and 
middle body characteristics, etc., of ships. Thus the subject of the proper manipulation and 
performance of the steering and guiding apparatus of the ship has received almost no atten- 
tion, while it has more to do with the ship’s retardation and its ultimate performance as a 
whole than some of the factors on which a great deal has been written. 
Recent contributions of no small significance have been made to our knowledge of this 
art by the fact that, thanks to the gyro compass, we are able to obtain continuous graphic 
records of high accuracy. Much of this record has been made with simultaneous graphic 
record of helm angle, making possible a searching investigation into the whole realm of re- 
sponse of seagoing craft to rudder and bringing in many other items touching general per- 
formance. This enables us to trace cause to effect and to observe just what each alteration 
in the mechanism has brought to pass in point of actual performance. Most valuable light 
has thus been thrown upon the whole art of steering ships, and especially has this been ex- 
tremely useful in the perfection of automatic steering. 
It has long been supposed that an efficient “iron quartermaster” would never be made, 
because it has been inconceivable that any mechanism could ever replace efficiently the species 
of intuition on which an expert quartermaster is supposed solely to depend for high efficiency 
performance. This seems to be corroborated by the fact that no two quartermasters seem to 
be able to steer, especially a large ship, with anything approaching equal efficiency. That 
intuition of the sort named plays only an insignificant part in proper handling of the helm 
was at a very early date shown by the very great improvement in steering by all quarter- 
masters upon the substitution of the gyro for the magnetic compass. 
The steering of ships, torpedoes, airplanes, dirigibles, etc., where the rudder is aft, pre- 
sents several problems, some of which, at least, are due to the fact that the controlling of the 
direction of such a craft is in constant unstable equilibrium. This is evidenced by the con- 
stant tendency of all ships to yaw off their course. 
That an instrument can be of material aid in the matter is shown by the fact that in the 
hands of almost any quartermaster a given ship often decreases its angles of yaw in a given 
sea from one-fourth to one-sixth by shifting from the magnetic to the gyro compass. As 
