Intro to Marine Navigation

Mission Statement

maritime nation, protect at sea, keep seas open and free

Nautical Charts

Graphic representations of areas of the Earth, in digital or hard copy form, for use in marine
navigation.

Course

The horizontal direction in which a vessel is intended to be steered, measured from north at 000° clockwise though 360°.

Heading

The direction in which a vessel is pointed at any given moment, expressed as angular distance from 000° clockwise through 360°

Bearing

The direction of one terrestrial point from another, expressed as angular distance from 000° clockwise through 360°. Is expressed as either true or relative bearing

Speed

The direction of one terrestrial point from another, expressed as angular distance from 000° clockwise through 360°. Is expressed as either true or relative bearing

Lines of Position (LOP)

-A line that is plotted on a chart with which our position lies. It may be taken from a visual aid,
RADAR or a celestial sight reduction.

Fix

A position derived from measuring external reference points, typically the intersection of three or more LOPs

Prime Meridian

The base line of Longitude from which
all lines of longitude are measured from. Based in Greenwich, England and runs from True North to True South.

Longitude

The angular distance between the Prime
Meridian (base longitude) and the meridian of a point on Earth. Measured 000°-180° East or West of the Prime Meridian. Lines of Longitude are commonly referred to as meridians

Equator

A great circle at latitude 0° that bisects the
Northern and Southern Hemisphere.

Latitude

The angular distance from the Equator (base
latitude) measured north or south from 000°-90° at the poles. Lines of Latitude are commonly referred to as Parallels.

Rhumb Line

A line, typically drawn on a chart, that is making the same angle with all meridians. It has a path with constant bearing relative to true north. loxodromic curve or loxodrome.

Great Circle Line

A line that represents the circular intersection of
a sphere and a plane passing through the sphere’s center point

Dead Reckoning

Determines a predicted position by advancing
a known position for courses and distances

Piloting

Involves navigating in restricted waters with frequent or constant determination of position relative to nearby geographic and hydrographic features.

Radar Nav

Involves using RADAR to determine the distance from or bearing to objects whose position is known. This is separate from collision avoidance

Satellite Nav

Uses radio signals from satellites to determine position

Cel Nav

Involves reducing celestial measurements taken with a sextant to lines of position utilizing spherical trigonometry either by hand or with computer programs.

Restricted Waters

Navigating less than 2 nautical miles from land or shoal water, typically in narrow canals, channels, rivers and estuaries

Piloting Waters

Navigating within 2-10 nautical
miles of land or shoal, typically as we go to a
harbor entrance or through bays and sounds and negotiating harbor approach channels.

Coastal Waters

Navigating within >10-30 nautical miles of land or shoal water

Open Ocean

Navigating over 30 nautical miles away from land or shoal water.

Phases of Navigation

National Geospatial Intelligence Agency

Produces charts and nautical publications
used extensively by the U.S. Military. Disseminates maritime safety information in the form of Notice to Mariners (NTM).

United States Naval Observatory

Scientific and military facility that produces
geopositioning, navigation and timekeeping data for the United States Navy and the United States Department of Defense. It is one of the oldest scientific agencies in the United States, and remains the country's leading authority for
astronomical and timing data for all purposes

National Oceanic and Atmospheric Administration

Produces charts and nautical publications used extensively by both the Navy and Merchant fleets. Primarily covers the coastal areas of the US and Great Lakes.

USCG

Maintains aids to navigation, provides updates for Navigation Warnings for US Districts and
produces Local Notice to Mariners. Publishes the Rules of the Road book that we use!

National Oceanographic Officer

Provides oceanographic products and services to all elements within the Department of Defense.

International Hydrographic Organization

Sets forth hydrographic standards to be agreed
upon by member nations. Ensures nautical charts produced by different nations have uniformity in design

International Maritime Organization

Coordinates international policy on maritime
matters. Adopts conventions and protocols for
safety at sea, such as International Regulations for Preventing Collisions at Sea (COLREGS)…or the Rules of the Road!

International Association of Marine Aids to Navigation and Lighthouse Authorities

Provides technical coordination, information
sharing and coordination of improvements to
visual aids to navigation around the world.