Using the Nautical Slide Rule
To simplify speed, time, and distance solutions, most Quartermasters use
a circular slide rule (fig. 8-2), commonly known as a nautical slide rule.
When you enter two known variables on the appropriate scales, the third
value can be found.
Figure 8-2. Nautical slide rule.
Do NOT rely solely on the nautical slide rule to calculate time, speed,
and distance problems. A problem will surely arise when the slide rule
is not available. Additionally, you cannot use a nautical slide rule when
taking advancement examinations.