Flashcards in Exam 4 Deck (115):
What is the largest circle that can be draw on the surface of a sphere and the shortest distance along the surface between any two points?
A great circle
The point of greatest latitude along a great circle track is the
What does a nautical chart represent?
Part of the spherical earth on a plane surface
Nautical charts are found in what two formats?
Paper and electronic
Name for things a chart shows
Depth of water, Shoreline, TOpographic features, aids to navigation
What helps a navigator be knowledgeable of the local area and to avoid possible dangers?
What are four uses of a navigational chart?
Plot courses, determine position, determine navigational options, determine depths or “soundings“
______________ Is the process of transforming the earths curved surface onto a flat surface.
What happens to a curved surface when transferred to a flat surface?
It will be distorted
What are the type of chart projections we will be concerned with?
Mercator, Conic and polyconic projection, Lambert conformal projection, and gnomonic projection
Which projection is most frequently used by Mariners?
Mercator projection is classified as a _______________, And normally tangent to the earths equator.
How do rhumb lines plot?
In a straight line.
___________ is a line that makes the same oblique angle ( not a multiple of 90*) with all meridians.
A rhumb line is a ___________ curve on the earths surface.
Mercator charts are constructed using what to determine spacing of parallels?
What is a meridional part equal to?
Length of one minute of longitude at the equator.
Points on the earths surface are transferred to a tangent cone.
Simple conic projection
A series of tangent cones are used to project points on the earths surface.
A secant cone for a conic projection with 2 standard parallels is a
Lambert conformal projection
A straight line on a lambert conformal projection represents an
Approximate great circle
A projection where points are projected geometrically from the center of the earth.
A gnomonic chart is referred to as a
Great circle chart
A ratio of distance on the chart to the actual distance represented on the earths surface.
What are the four chart scale categories?
Sailing charts (1-600000 or greater) voyages
General charts (1:150000-1:600000) coastwise
Coastal charts (1:50000-1:150000) entering or leaving bays
Harbor charts (1-50000 or less) harbors and narrow waterways
What is N0S?
National ocean service, a sub agency of in NOAA, which publishes charts covering coastlines and adjacent areas of the United States and its possessions
What is NGA?
National geospatial intelligence agency, which publishes charts covering the rest of the world. Formerly named NIMA and DMA.
Chart accuracy depends upon
Hydrographic surveys and weather
Updates or needed corrections to a chart or posted through
Notice to mariners
How often are notice to mariners posted?
Weekly, tracked through 52 weeks of the year and labeled as “week number/year”
A reference book used to determine data on a chart is
Chart number one
The height of water that is printed on a chart based on a vertical reference points such as mean lower low water is the
Heights of objects usually given and Heights above
Mean high water
The date a chart was first printed, at the top center of the chart
Date printed in the lower left corner of the chart which contains notice to mariners up to that date.
What contains corrections from notice to mariners between new edition and date of revised chart?
What contains limit of corrections and is primarily the same chart as the last new Edition also containing the last Epoch of magnetic variation?
The maximum distance at which the curvature of the earth will permit a light to be seen from a particular height of eye without regard to the luminous intensity of the light is
What are two ways to determine geographic range?
By using the geographic range table in the light list, or by computing the formula.
What is the formula to compute geographic range?
1.17 Times the square root of height 1+1.17 times the square root of height 2
The maximum distance at which a light can be seen under existing visibility conditions is
What takes no account of the elevation of the light, the observers height of eye, the curvature of the earth, or interference from background lighting?
The maximum distance at which a light can be seen in clear weather is defined by the international visibility code (meteorological visibility of 10 nautical miles)
Aids to navigation
ATONS are also referred to as
ATONS assist navigators by marking
Prominent features in navigable waters
In the United States aids to navigation are maintained by who?
US Coast Guard
Aids to navigation can help Mariners find
Safe water, anchorages, information of the area.
Name some types of navaids
Light houses, buoys, ranges, placards, radar transponders, shore lights, bridge lights
Lights may be
Fixed or floating
Prominent lights are usually placed
At Harbor or port entrances and isolated dangers
What are lights good for?
Determining fixes, and are costly and becoming highly automated
Lights on docs, peers, buildings, are used to assist mariners into
How are buoy lights powered?
By battery or solar
What do red bridge lights indicate?
Peers and other parts of the bridge, or show that drawbridges are closed
What do green lights Mark?
Shows the drawbridges are open, and mark the centerline of the Navigable channel thru fixed bridges
White bridge lights
Draw attention to the navigational obstacle
International Association of lighthouse authorities
IALA promotes uniformity among different countries in there
Lighthouse and buoyage systems
Rangers are used to
Steer a desired course
Ranges have both day marks and night marks. What are they?
Day marks are vertical striped boards, and night marks are colored lights
Day marks are represented by what on a chart?
K represents a
Square or rectangular board
The second letter in a Daymark represents the
The third letter in a Daymark represents the
Floating aids to navigation
Buoys are usually used to mark
A channel, shoal/obstruction, Anchorage
Name five types of buoys.
Lateral marks, isolated danger marks in cardinal marks, safe watermarks, special marks, information/regulatory marks.
A beacon is a
Fixed, not floating aid to navigation
A beacon with lights is called a
Unlit Beacons are called
Lateral marks should be passed
To port or starboard
The u.s is in IALA-
Red, right, returning theory
IALA-A reverses the
Colors, not the shapes
A nun buoy is shaped like a
A can buoy is shaped like a
What are the two types of isolated danger marks?
Isolated danger mark’s - US
Cardinal marks – international
Isolated danger marks do not indicate the direction in which to pass, but
Which area to avoid
The shapes for an isolated danger mark will be
Two black Spheres
The lighting for an isolated danger mark will be
Isolated danger mark will be black with horizontal
What do cardinal marks indicate?
The deepest water near a point of interest lies in the direction named by the mark, the safe side to pass a danger, are always to the named side of the point of interest, and will always have yellow/black bands, two black cone top marks, and white light with rhythm shown.
Uninterrupted flashing equals
Three flashes per group equals
Six flashes per group plus a long flash equals
Nine flashes per group equals
Traffic separation scheme marks, spoiled ground marks, cable or pipeline area marks, military exercise zone marks, recreation zone marks, or oceanographic data acquisition system buoys are examples of
What color are special marks?
Yellow, and any top Mark will be a yellow X (top marks are optional)
Special Mark lights will always be
Yellow, usually with a fixed or slow flash characteristic
What has an alternating blue and yellow flashing light, and put in place until the lateral or cardinal buoy is deployed?
Emergency wreck buoy
What are the five types of sound signals?
Diaphones, horn’s, sirens, whistles, bells/dong’s
A sound produced by slotted piston that is move back-and-forth by compressed air, often known as a two tone signal is a
Sound produced by a disc diaphragm operates pneumatically or electrically is a
Sound produced by disc or cup shaped rotor operated pneumatically or electrically is a
Sound produced by compressed air emitted thru a slot into a cylindrical bell chamber is a
Sound produced by a mechanical hammer
Are sirens used in the u.s. ATONS?
Red buoys have
What color buoys have odd numbers?
The buoys farthest out to sea have what numbers?
Buoys that are not solid green or red are not numbered and therefore will be
Named by a letter or letters
Lights on red or green lateral buoyswill be
Occulting, isophase, or regularly flashing less than 50 per minute
A quick flashing buoy (more than 50, less than 80) is marking
Caution or danger
A buoy flashing a Morse code letter appx 8 times a minute is a
Safe water buoy
Red right returning
Clockwise inland waters coming from seaward
If traveling in a clockwise direction what buoys do you keep between you and land?
A vessel is proceeding seaward if traveling
An inland waterway that runs along the Atlantic and gulf coasts from New Jersey to Mexico is an
An enroute sailing direction is
More detailed and 37 publications describing coastline, ports and harbors
Planning guide is a zoomed out version
With 10 publications describing ocean basins
Coast pilots is published by
National ocean service
Coast pilots info includes
Local practice, pilotage, anchorages, comms, weather, routing
Light list published by