NS100

Navigation Instruments

Fundamentals of

Naval Science

Measurement of Direction Azimuth Circle

Measurement of Direction Telescopic Alidade

Shooting a Bearing• Look through the rear sight slot• Line up forward wire with center of slot and

object• Look into prism to obtain bearing (true or

relative)• Record bearing for plotting.

Measurement of Distance Radar

Measurement of Distance Stadimeter - very accurate under 2000 yards

Measurement of Speed Terms:

Speed over Ground - “True” speed, or speed relative to the earth.

Speed through the water - Relative speed between the water and the ship, not accounting for the effect of current or seas.

Measurement of Speed Impeller Log

Measurement of Speed Pit Log

Dynamic pressure

static pressure

Measurement of Speed

Doppler Speed Log – can be extremely accurate

Shaft RPM vs. speed

Measurement of Depth

Fathometer

Piloting Instruments

•Divider and Drawing Compass •Parallel Ruler/Parallel Plotter/Parallel Motion Protractor (PMP) •Three-Arm Protractor