Aids to Navigation

Question 1

The art of navigation has since expanded from using the stars and planets to sophisticated electronic navigation systems, but one thing remains unchanged

Answer 1

Regardless of the methods used, the safe and confident navigation of a vessel is an absolute necessity.

Question 2

Basic Piloting Tools

Answer 2

Compass
Parallel Rulers
Rolling Plotter
Pencils
Dividers/Drafting Compass

Question 3

Compass

Answer 3

The magnetic compass is used to steer a course, and to determine position by sighting “bearings” to charted landmarks

Question 4

Parallel Rulers

Answer 4

Two rulers connected by moveable straps that allow the rules to separate while staying parallel. They are used to transfer directions from a compass rose to plotted courses and lines of bearing. They are always “walked” so that the top or bottom edge intersects the compass rose center to obtain accurate readings.

Question 5

Rolling Plotter or Weem’s plotter

Answer 5

used instead of parallel rulers. A rectangular pieces of plastic with a set of lines parallel to the long edges, and semi-circular scales. The center of the scales is at or near the center of one of the longer sides and has a small circle or bullseye. The bullseye is used to line up on.a longitude line so that the direction can be plotter read directly from the scale without having to roll it to a compass rose.

Question 6

Pencils

Answer 6

sharp #2 pencils should be used

Question 7

Dividers

Answer 7

Instruments with two pointed legs, hinges where the upper ends join. They are used to measure distance on a snake and transfer that distance to a chart.

Question 8

Drafting compass

Answer 8

Has a pointed leg hinged with a leg to which a pencil is attached. This is best for plotting range and distance.

Question 9

Plotting Latitude

Answer 9

Step A: Using dividers, select the desired measurement fr0m the latitude scale. Measure fr0m the side of the chart nearest to the desired position.

Step B: Transfer this measurement to the line of longitude that is closest to the desired longitude.

Step C: Using a parallel ruler or plotter, draw a horizontal pencil line fr0m this point to the approximate area of the desired longitude line.

Question 10

Plotting Longitude

Answer 10

Step D: Using dividers, select the desired measurement fr0m the solid line of longitude nearest to the desired longitude. Measure fr0m the top or bottom of the chart, whichever is closest to the latitude line drawn in Step C.

Step E: Transfer this measurement up or down on the solid line of longitude and make a pencil point along the line of latitude drawn previously.

Step F: Circle the position and make sure to label it properly. There are a number of ways that latitude and longitude can be plotted, or determined, on a chart. The conventional method is to use dividers, and parallel rulers, a rolling plotter, triangles, or some other similar straight-edge device.

Question 11

What is the best plotting device?

Answer 11

There is not one, just personal preference.

Question 12

Which is given first, latitude or longitude

Answer 12

latitude

Question 13

Parallels of Latitude
XX - YY.Z
Distances

Answer 13

XX = Degrees of Latitude from 00 at equator to 90 at poles. Each degree is 60 nautical miles

YY = Each degree is divided into Minutes. One minute = one nautical mile.

.Z Each minute is divided into tenths of a minute or 1/10 of a Nautical Mile

Question 14

Meridians of Longitude

XX - YY.Z

Answer 14

Measures along the top or bottom of the chart

XX = degrees of longitude from 00 Prime Meridian either East or West. Prime meridian passes through Greenwich England

YY = Each degree is divide into minutes. One minute only equals one Nautical mile at the Equator.

.Z Each minute s divided into tenths of a minute.

Question 15

The International dateline

Answer 15

A Meridian of Longitude 180 degrees from the Prime Meridian