Master of vessels less than 24mtrs & Master 5 Navigation
(Includes extracts courtesy of A.N.T.A, Ranger Hope © 2008-2016)
Charts and Publications
Position and Direction on the Earth Surface
Properties of a Mercator
Locating and Identifying Navigational Charts and publications
Admiralty list of lights
Notices to Mariners
Types of Charts and information provided
Symbols and Abbreviations
In order to define the exact position on the Earth’s surface it is necessary to have two co-ordinates. Those customarily used are Latitude and Longitude. Position may also be expressed in relation to a known geographical position.
Example 15 miles East of Burnett Head Lighthouse.
Both Latitude and Longitude are given in the units
DEGREES (°) MINUTES ( ¢ ) SECONDS ( ² )
There is one plane which perfectly bisects the earth midway between the two poles. The line formed where this place meets the surface of the earth is called the equator.
All lines on the earth’s surface which run parallel to the equator are called parallels of latitude. They are named north or south depending on which side of the equator they lie.
Latitude is measured by the angle at the earth’s centre between the place in question and the equator. Latitude is therefore between 0° and 90°, north or south.
Angle BAC (or arc BC) is the latitude of C
Figure 1.1: Definition of Latitude
There are a great number of circles which pass through both poles and form circles on the earth’s surface. These circles cut the equator and all parallels of latitude at 90 degrees. They are called meridians. Unlike the measurement of
latitude there is no natural reference point.
The reference meridian selected is that which passes through the old
All other meridians are named east or west, from 0° to 180°, depending on the angle at the earth’s centre between the prime meridian and the one in question. This provides the second co-ordinate, called longitude.
The longitude of X and Y is the same, as is
the longitude of A and B. (Note that the
angle could be measured at any point on the
earth’s axis, including either pole).
Figure 1.2: Definition of Longitude
Direction is the position of one point relative to another, customarily expressed as the angular difference in degrees, usually from NORTH or the SHIP’S HEAD, without reference to the distance between them.
Figure 1.3: Definition of Direction
On the navigational chart the direction in which a place or object lies from the vessel is called the true bearing and is measured from NORTH (0°) in a clockwise direction through 360°.
Distance on the earth is customarily expressed in Nautical miles by Mariners, and is the spatial separation of two points, in this case A and B.
Figure 1.4: Definition of Distance
For most navigational purposes the nautical mile is considered to be the length of 1 minute of Latitude and this is the scale one should use.
NEVER use the Longitude scale to measure distance.
The navigator is required to find the following characteristics in a chart:
Coast lines should retain the same shape as they have on the Earth’s sphere.
The lines of Latitude and Longitude should be east - north and west - south respectively. They should cross at right angles as on the sphere.
A straight line drawn on a chart between any two places should give the distance and direction between them. The angle at which this line cuts any meridian should give the TRUE course to steer.
The chartmaker has the problem of representing the rounded surface of the earth on a flat piece of paper. To some extent this is satisfied in the Mercator projection, but not without distortion of Land Mass sizes, unless they are near the Equator.
Figure 1.5: World Mercator Projection
The main feature of the Mercator projection is that both meridians and parallels are expanded at the same ratio with increased latitude. Expansion is the same in all directions and angles are correctly shown. Rhumb lines appear as straight lines, the directions of which can be measured directly on the chart (angle 2°).
Bearing and course lines are Rhumb lines.
Distances can be measured directly, for practical accuracy, but not by a single distance scale over the entire chart.
The latitude scale is customarily used to measure distances, the expansion of the scale being the same as that of distances at the same latitude.
We will first consider the various publications.
Certain publications are necessary to supplement the information a navigator can obtain from the chart.
Sailing Directions (Pilots)
These are intended to be read in conjunction with the charts quoted in the text. They are published by the Hydrographer of the Navy or by Local Government. The latter generally being more up to date.
They need to be kept up to date by the latest supplement and Notice to Mariners.
An example of the title and contents is shown on the following page.
These give full details of all official navigational lights and are available from Hydrographic Office.
They are corrected from Australian Notices to Mariners issued fortnightly. See an example of a cover sheet on the following page.
Each light within the book is given a number, Latitude and Longitude etc.
List of Lights
These are published annually by the Hydrographic Office covering all Australian Ports, Papua New Guinea and Solomon Islands.
Locally published tables are published by State Governments and often give other useful information.
(Example) Queensland Transport produce annually ‘The Official Tide Tables and Boating Safety Guide’
This covers tidal predictions, the weather, fishing guide etc.
Tidal calculations will be explained later in Outcome 5.
These are issued in fortnightly editions, numbered consecutively, by the RAN Hydrographic Service.
They contain corrections for the following.
Sailing Directions (Pilots)
List of Lights
Admiralty List of Radio Signals
The following pages give examples of corrections from Edition 30 (1996.)
They can be obtained free of charge from the Custom House or Shipping Offices.
Australian Notices to Mariners
Contained within the Notices to Mariners are navigational warnings.
Two types of navigation warnings are originated by the Federal Sea Safety Centre and broadcast by Telstra Coast Radio Stations.
The first are NAVAREA which are long range warnings.
The second type is the AUSCOAST warning.
Examples of these are given on the following page.
In Australian waters charts can be identified using 2 catalogue sheets.
sheet covers from Port Clinton in
on the above sheet is
Southern sheet covers the rest of
The sheets give the Chart Number, Title, Scale and Current Edition Date.
On the back of each sheet are various miscellaneous charts and publications.
Their numbers are: Southern AUS 5020B
Northern AUS 5020A
The catalogue charts should not be used for navigation but are invaluable for planning a voyage and ordering charts and publications required.
A nautical chart is a graphic representation, on a plane surface, of a navigable area on the earth’s surface. They are available both as paper charts and as electronic charts. They differ from a map in recording both position and elevations from survey with a reliability statement (zones of confidence). There will be an updating service provided for government charts to maintain their high accuracy. It is an essential tool of the navigator and without it a position cannot be fixed relative to navigation aids, the coastline or hidden dangers.
A chart will show the depth of water by soundings and depth contours, shoreline, topographic features, nature of the bottom, tidal streams, magnetic variation etc. for the area.
These are the smallest scales and are used to show Ocean Routes, Ocean Currents, Magnetic Variation.
are the next scale and are typically 1=10,000,000, covering large areas such
for navigation where courses lie outside outlying
reefs and shoals. Typically 1:1,000,000
AUS423 Eddystone Point to Port
Used for inshore navigation where courses lie inside outlying reefs and shoals. Typically 1:150,000 AUS701 Vrilya Pt. to Duyfken Pt.
for harbours and rivers giving great detail.
1:7,500 Wyndham Wharf
Find a chart and identify the following information while reading the text.
The catalogue number of the issuing authority is shown in the lower right and upper left margins.
The number will be preceded by letters
Examples being AUS........... Australian
NZ............. New Zealand
B.A............ British Admiralty
INT........... . International
Figure 1.6: Chart Number
Figure 1.7: Chart Printing Date
Appears in the upper right margin.
Appear in brackets in the lower right margin.
Figure 1.8 Chart Dimensions
Title or Legend
This is placed in a position on the chart so that no essential navigational information is obscured often over land areas.
It usually includes.
Units of Sounding - Fathoms or Metres
Notes on Heights
Projection - Mercator, Gnomonic
- Transverse Mercator
Frequently found under the tide, but may appear elsewhere if space so requires in Tidal information and Caution notes.
This appears in the centre bottom margin. It may include new edition and large corrections.
Figure 1.9: Chart Title and Date of Publishing
The year and correction number are placed in the lower left margin as they are entered on the chart from ‘Notices to Mariners’, a small section of which is shown in Figure 1.10.
Temporary and provisional notices should only be entered in pencil on the chart and their number never entered in the small correction area.
Before purchase you should ensure that the chart is corrected to the latest ‘Notices to Mariners’.
need to be kept up to date by the Australian Notices to Mariners issued fortnightly.
Copies can be sighted free of charge from official Chart Agents and
Custom Houses in major
Figure 1.10: Small Corrections
Chart positions are defined by Latitude and Longitude or Bearing and Distance.
The Latitude scale is on the sides of the chart and used for distance measurement.
One minute of Latitude is equal to 1 nautical mile. It also defines the position North or South of the equator.
Figure 1.11: Latitude Scale The Longitude scale is across the top and bottom of
the chart and defines the position East or West of Greenwich. Figure 1.12: Longitude Scale To define position by bearing and distance we use the compass
rose, Figure 1.13 for true bearing and the Latitude scale, Figure 1.14 for
measuring distance. Figure 1.13: Compass Rose Figure
1.14: Latitude Scale All
lines and symbols on a chart mean something and are contained in publication
(5011 Symbols and Abbreviations). However, certain symbols and abbreviations
the student should be able to recognise without reference to 5011. Notably Rocks, Wrecks and Obstructions IALA Buoys and Beacons Light Characteristics The more
common natural features to your area and certain areas of limitations. The questions
at the end of this outcome give an indication of the type of symbols and abbreviations
the student should be able to recognise. Particular
attention should be paid to water depths and nature of the bottom.
Symbols and Abbreviations
Figure 1.11: Latitude Scale
The Longitude scale is across the top and bottom of the chart and defines the position East or West of Greenwich.
Figure 1.12: Longitude Scale
To define position by bearing and distance we use the compass rose, Figure 1.13 for true bearing and the Latitude scale, Figure 1.14 for measuring distance.
Figure 1.13: Compass Rose
Figure 1.14: Latitude Scale
All lines and symbols on a chart mean something and are contained in publication (5011 Symbols and Abbreviations). However, certain symbols and abbreviations the student should be able to recognise without reference to 5011.
Notably Rocks, Wrecks and Obstructions
IALA Buoys and Beacons
The more common natural features to your area and certain areas of limitations.
The questions at the end of this outcome give an indication of the type of symbols and abbreviations the student should be able to recognise.
Particular attention should be paid to water depths and nature of the bottom.