Navigation theory

Ten questions with a minimum of 5: instruments, radar, AIS and tide concepts.

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Electronics

Head-up radar: relative bearings. North-up: true bearings. Gain adjusts sensitivity.

AIS uses VHF and receives data from other boats. It is compulsory from 300 GT. Raster charts are copies of paper charts.

Activities

• Navigation instrumentsWhat each device at the chart table measures.
• Navigation calculationsTotal correction, courses, departure and dead reckoning, step by step.
• Tide trainerWork out soundings, water under the keel and tide times, step by step.

Questions in this unit

• With a Head-Up radar we can obtain:
• The abbreviation COG means:
• On the definition of the equator, mark the CORRECT statement.
• On notices to mariners publications, mark the INCORRECT statement.
• Which abbreviation refers to bearings on a radar set?
• When transferring the GNSS position to a paper chart, it is vital to:
• Approaching dense traffic with showers about, it is advisable to run the radar so that:
• What does XTE stand for?
• The resultant vector of course and speed through the water, plus the current’s set and rate, is:
• Official vector electronic charts are:
• Notices to mariners are used to:
• The angle between the wake left by the boat and her fore-and-aft line is called:
• To set legal time, the Earth was divided into:
• On a “north-up stabilised” radar display, we read directly:
• Which pair of values can give the total correction?
• Local civil time is the time:
• On the definition of meridian, mark the CORRECT statement.
• To work out the total correction by formula from a transit, we need only:
• On the definition of latitude, mark the CORRECT statement.
• The total correction:
• In fog in heavy traffic, our boat’s AIS allows us to:
• In sailing directions:
• When will two vessels sailing in the same area have the same total correction?
• The true bearing of an object is obtained:
• What are the two kinds of official electronic nautical charts that may be carried?
• If the true course equals the water track, we can conclude without doubt that:
• Corrections to Spanish sailing directions are given in one PDF per volume, listing all changes since the last edition. This is done through:
• Polaris is used as a reference to obtain the compass total correction. It belongs to the constellation:
• Time zones are exactly how wide?
• The civil time elapsed between two successive passes of the Sun over Greenwich’s lower meridian is defined as:
• Correcting and updating Spanish sailing directions, lists of lights and fog signals, and charts is the job of:
• In GPS-GNSS marine navigation, “WPT” means:
• Local magnetic variation and its effect on the compass depend on:
• On recreational passages, as to electronic charts:
• At the Earth’s centre, an observer’s latitude forms an angle equal to:
• Steering 360º true for 60 nautical miles without change, you will have covered on the Earth’s surface:
• Every day the date changes on a particular meridian. It is:
• On a “head-up” radar display, ship echoes move:
• The Earth’s equator is 40,000 km long, which in nautical miles is:
• In heavy seas we may see an effect on the radar screen called:
• The value of local variation depends on:
• The Tropic of Capricorn has a latitude of:
• Which equation gives the total correction using Polaris?
• On a yacht under way, between her true course and the compass course lies the angle between:
• In GNSS (GPS) terms, “SOG” means:
• Regarding head-up and north-up radars:
• Under the rules, can paper charts be replaced by electronic ones?
• To update Spanish nautical charts, we consult:
• If we press “MARK” on our GPS plotter, it gives us:
• How many degrees of arc does the Sun travel in one hour?
• Echo movements on the radar screen are:
• If we could walk all the way round a great circle of the Earth, we would cover:
• The radar “rain clutter” control is used to:
• The 180º meridian, or Greenwich lower meridian, is the meridian:
• When the Sun passes twice in succession over the Greenwich meridian, the civil time elapsed is called:
• On a north-up radar with a built-in GPS compass, bearings taken to echoes are:
• Pressing the radar “GAIN” control gives:
• On GPS-GNSS equipment, “COG” means:
• Using an electronic chart app, the term “WPT” means:
• The AIS acronym stands for:
• The meridian through an observer’s position on the Earth is:
• What is official time (HO)?
• The value of local magnetic variation affecting compasses depends on:
• Steering true course 220º with a NW wind giving 5º leeway (uncorrected), the yacht will be:
• With a head-up radar on, we alter 15º to port and see that:
• With a big swell, waves show on the radar and can hide boats or floating objects. This is reduced with the filter:
• The time zone bisected by the Greenwich meridian is:
• The circles on the Earth perpendicular to the polar axis are:
• The small circle in the northern hemisphere at latitude 23º 27′ N is:
• The water track results from the action of:
• The equation for the compass total correction from the compass azimuth of Polaris is:
• Spanish nautical charts are kept up to date through:
• On a head-up radar, if we alter 20º to starboard, the coastline on screen will move:
• The semicircle running from North Pole to South Pole through the observer’s position is called:
• The “course made good” (rumbo efectivo) results from:
• Sailing south from the Canaries, when we cross the 23º 27′ N parallel we have passed the:
• By how they are produced, electronic charts fall into two main groups:
• The Greenwich meridian is the axis of time zone:
• An observer’s position is set by latitude and longitude, and also coincides with:
• When the yacht’s masts block the radar beam, the screen shows:
• To fine-tune radar receiver sensitivity and resolve targets better, we use:
• Electronic charts can:
• In GPS/GNSS, the acronym SOG refers to:
• The Automatic Identification System is known in Spanish by the acronym:
• The Automatic Identification System works on the radio band:
• Each time zone spans an arc of the equator of:
• Which parallel does the Tropic of Capricorn lie on?
• The Earth’s equatorial circle measures:
• To reduce the effect of waves on the radar screen, we use:
• Greenwich civil time (HCG) coincides with:
• How wide are time zones along the equator?
• The yacht’s course made good results from:
• For rhumb-line navigation, the charts used are:
• On a Mercator chart, a true course plotted on it:
• If we take an azimuth of Polaris (assumed at the pole) with the magnetic compass, it is:
• Publishing Notices to Mariners is the job of:
• A basic (head-up) radar provides, among other things:
• The compass total correction can be obtained:
• In GPS (GNSS) terms, COG (course over ground) is:
• The angle we measure with the compass from COMPASS NORTH to the line of sight of a lighthouse is the:
• With the radar set to north-up stabilised, what do we get when we point at an object?
• What effect appears on the radar screen when masts block the radar beam?
• Bearings and ranges on the radar screen are obtained with a radar that is:
• The effect of sea waves on the radar screen is reduced with:
• In the radar “SETTINGS” menu, to reduce rain on screen we use:
• A yacht at 36º North has an arc of meridian to the equator of:
• Notices to Mariners are:
• An observer’s position on the Earth is set by:
• The most common radar errors are:
• The parallel at latitude 23º 27′ S is called:
• In Spain, official navigation publications (charts and books) are entrusted to:
• The great-circle arc from pole to pole, crossing the equator and parallels at right angles and passing through the observer, is called:
• How many satellites make up the GPS positioning system?
• A “head-up” radar means that:
• Radar is affected by:
• Difference of latitude is:
• Official time (Ho) of a place:
• If we sail to a place at longitude 70º W, what is its time zone?
• Parallels are:
• True course is obtained by adding:
• The Raster Navigational Chart (RNC):
• For calculations, the angle between true course (stern-to-bow line) and the water track, due to a beam wind, is the angle of:
• A true bearing is defined as:
• The small circles of the Earth perpendicular to its axis are:
• By how electronic charts are resolved, they fall into two main groups:
• The “rain clutter” effect on the radar screen is due to:
• Greenwich civil time (HCG) is defined as:
• The total correction of the magnetic compass is defined as:
• What factor does magnetic variation depend on?
• On radar equipment, disturbances include:
• What do the letters EBL on a radar stand for?
• The electronic system letting ships report their position and relevant information so other ships or coast stations can know it is:
• How far is the Arctic Circle from the North Pole?
• Parallels:
• Sailing with the radar head-up:
• The system used by today’s satellites is:
• With wind and current, relative bearings are taken with respect to:
• The COG function refers to:
• The time difference between two places is:
• Radar range depends, among other things, on:
• The Arctic Circle:
• When the Sun, Earth and Moon are in a straight line, we get:
• Information to update the magnetic variation is found:
• The water track is:
• The acronym SOG on a GNSS unit stands for:
• When is your latitude 0º?
• If magnetic variation is zero, the compass course equals:
• On a transit of two lighthouses, the total correction found from its bearing applies to:
• Sailing directions can be corrected with:
• AIS can be an important aid to preventing collisions:
• The reference system used to determine the geographical coordinates of points on the Earth is called:
• From each pole to its polar circle there are:
• Regarding GNSS:
• If deviation is zero, the compass course equals:
• The ends of the Earth’s axis are:
• Two ships with the same longitude are on the same:
• The GNSS acronym for estimated time of arrival is:
• About official RNC electronic charts:
• The Tropic of Cancer is at about latitude:
• AIS is a system that lets:
• If magnetic variation is zero:
• Corrections to charts, sailing directions and catalogues, firing-exercise notices and latest navigation news appear in:
• The great circles perpendicular to the parallels:
• The angle between the true course and the water track the boat makes is called:
• When a vessel is at latitude 23º 27′ S:
• Which expression is correct?
• If we work out a total correction on a given heading:
• Regarding GNSS, which statement is correct?
• Drift (“deriva”) is defined as:
• About meridians:
• On a GNSS unit, the position of a person overboard is shown by:
• We can work out the total correction:
• Which statement is FALSE?
• For the best picture on a radar screen we should adjust:
• On updating magnetic variation:
• Vector charts:
• Regarding local civil time (HcL):
• Meridians:
• Which statement is correct?
• The compass course is:
• Updates to official charts, to include new dangers, are made through:
• Official ENCs (Electronic Navigational Charts) are:
• AIS is used to:
• What is the great circle that is the origin of latitude called?
• How can the total correction (Ct) be found?
• What is the angle between the course made good and the true course called?
• To obtain the compass course (Ra) we use:
• With the radar set to head-up:
• What is departure (“apartamiento”)?
• On GNSS, the “XTE” indication means:
• On total correction, which answer is right?
• Ship’s clock time (HRB):
• All observers on the same parallel:
• Which statement is FALSE?
• On GNSS equipment, estimated time of arrival is shown as:
• Legal (zone) time:
• When deviation is zero:
• The real course the boat makes under the combined action of wind and current is called:
• The types of electronic charts are:
• Which statement is FALSE?
• On AIS, which answer is correct?
• Regarding the local meridian, which answer is correct?
• Local civil time (HcL) is:
• When we find total correction from a transit, the deviation obtained corresponds to:
• The angle between the vessel’s wake and her centreline is:
• On electronic charts, which answer is correct?
• Clutter echoes may swamp a radar screen and hide targets if we set too high:
• On AIS, which answer is correct?
• The great circle on the Earth’s surface perpendicular to its axis is called:
• Can a GNSS position be put straight onto the paper chart?
• When using the sea clutter control:
• Crossing a transit, we take its compass bearing. To work out the compass total correction:
• Wind pushes a boat sideways, so her direction of travel differs from the true course. The angle between them is:
• What is AIS?
• Raster charts:
• Choose the correct option:
• Magnetic variation depends on:
• Steering a steady compass course South in Algeciras Bay, the boat’s fore-and-aft line drifts along the shore. With no current, the cause is:
• What is the effect of turning radar gain up to maximum?
• What is the function of a GNSS datum?
• What is the electronic charting system that represents each chart object as a vector called?
• What is the Automatic Identification System (AIS) for?
• At roughly what latitude does the Tropic of Cancer lie?
• The polar circles are located:
• What does a magnetic compass’s total correction depend on?
• Notices to Mariners give the corrections to be made to:
• To take a bearing and range with the radar we use the functions:
• The Automatic Identification System (AIS) can provide:
• Meridians are:
• The boat’s course relative to the seabed when affected by current and no wind is called:
• The best display of echoes on a radar screen can be spoiled by:
• If we find total correction from a transit, the deviation obtained is valid for:
• The quality of echoes on the radar screen can be affected by:
• On GNSS equipment, course made good is shown by the acronym:
• What information can a GNSS installation give us?
• Which kinds of electronic chart are specially designed for marine navigation?
• Choose the correct option about the Earth’s axis, equator and meridians:
• Which parallel has a latitude of about 23° 27′ S?
• Which equipment works because some electromagnetic waves reflect off objects and return to their source?
• On a radar we can find the bearing or relative bearing of an echo with:
• Official ENCs of the Spanish coast are produced by:
• The water track is defined as:
• Total correction can be found by:
• What is the radar on board for?
• In navigation, what does the datum do in a GNSS unit?
• Vector electronic charts are known by the acronym:
• What are the small circles perpendicular to the Earth’s axis called?
• Compass deviation equals the angle between:
• Sailing with wind but no current, what is the angle between the centreline and the boat’s wake called?
• Which nautical publication describes, among other things, the detailed features of the coast and its dangers?
• What is the time a government sets for its territory called?
• In heavy rain or hail, which radar controls should we adjust to filter weather interference and see real echoes better?
• On a GNSS screen, what does WPT mean?
• What happens if we plot a GNSS (WGS84) position on an old paper chart with a different datum, without corrections?
• AIS transmits and receives dynamic and static data on which band?
• Why is Polaris especially suitable for finding the compass total correction (Ct)?
• Sailing with current but no wind, what is the angle between the centreline and the track over the ground called?
• On a GNSS screen, what does XTE mean?
• Do ship’s clock time (HRB) and legal time coincide?
• Longitude is defined as:
• On a GNSS unit, what is XTE?
• Leeway is:
• Drift (“deriva”) is defined as:
• Which statement is CORRECT?
• About the kinds of electronic chart:
• What is the Automatic Identification System (AIS)?
• What is an ENC (Electronic Navigational Chart)?
• The chart carriage requirement states that:
• AIS is a data-transmission system working in which band?
• Choose the CORRECT statement about magnetic variation:
• Meridians are:
• A boat meets a current from ahead of 3 knots and the GPS reads a speed of 4 knots. What is the SOG at that moment?
• Difference of longitude is:
• How do we correct sailing directions?
• Magnetic variation:
• If a berthing quay is considerably changed in length by harbour works, what will we do with the harbour plan?
• What are the Tropics and where are they?
• Performance standards provide for radar systems of:
• The sign of leeway, by the side the boat is set to, can be:
• The GNSS system works by means of:
• What radio device shows the outline of the coast, other ships and objects at sea level?
• What is the “Datum” in electronic navigation?
• On leeway and drift, choose the INCORRECT statement.
• The course made good is, in general:
• The AIS system:
• By the definition of a meridian:
• Choose the CORRECT statement on compass deviation.
• The great semicircle of the Earth running from pole to pole is called:
• Sailing towards the Caribbean as crew on a yacht, the latitude where our course crosses the Tropic of Cancer will be:
• Which radio band does the Automatic Identification System (AIS) use?
• Besides changing the vessel’s speed, sea currents affect the course through:
• The Arctic Circle is the parallel of latitude:
• What is drift?
• The terms SOG and COG mean, respectively:
• Mark the INCORRECT statement.
• What does SOG mean in navigation?
• On passage it is important to note GNSS positions on the paper chart. For this we must take into account:
• Among other things, sailing directions contain data on:
• According to the definition of the prime meridian:
• On ECDIS (Electronic Chart Display and Information System):
• By definition, the compass course generally differs from the true course because of:
• What can stop a pleasure boat’s AIS detecting a nearby boat?
• On AIS:
• What are “AVURNAVES”?
• What is compass deviation?
• On using radar: to adjust our set’s tuning we use the control:
• On AIS: although generally recommended, it is compulsory for vessels of at least:
• If the radar scanner is fitted aft of a thick mast, it blocks the beam, causing:
• With a basic “North-up stabilised” radar we get:
• Boats in the same area experience:
• A RACON beacon provides:
• On notices to mariners publications:
• Universal Time is:
• On the definition of the equator on the terrestrial sphere, mark the INCORRECT statement.
• In coastal navigation, very weak echoes appear on the radar. Although on a suitable range, the coastline does not show. In general, how could the radar be adjusted to show it?
• The tropics are the two parallels lying respectively:
• By definition, true course is the course:
• In marine navigation, the total correction is the angle between:
• By definition, the effective course is the course:
• On notices to mariners publications, mark the CORRECT statement.
• On notices to mariners publications, mark the INCORRECT statement.
• Legal (official) time is:
• What is a datum in the GNSS context?
• True course is the angle between:
• On the different courses, mark the INCORRECT statement.
• On ECDIS, mark the CORRECT option.
• Using radar for coastal navigation, when taking bearings and ranges remember that:
• Knowing only the true and compass bearings of a transit:
• Effective course is defined as
• The ECS (Electronic Chart System)…
• This automatic navigation aid for identifying ships operates on radio band…
• On the terrestrial sphere, the equator is a great circle about how long?
• On time: time zones span on the equator a longitude width of
• Using GPS (GNSS): in GPS vocabulary, WPT is used to define:
• On electronic charts: there are two electronic chart display systems:
• The small circle parallel to the equator at latitude 23º27′S is called:
• If you are sailing on true course (Rv) North or 360º and run 60 nautical miles, you will have made:
• RASTER nautical charts (RNC):
• The Automatic Identification System (AIS):
• In “Head Up” radar mode, for radar fixes you take
• On tides: the lowest astronomical tide (bajamar escorada) is the tide level that:
• If we sail on true course (RV) = 120º and a SW wind gives us 5º of leeway, we will make a course of:
• If we want to fine-tune the radar’s receiver sensitivity and gain echo resolution on screen, we will use:
• The Global Positioning System uses a series of acronyms for its functions. What does MOB mean?..:
• The effect of “drift” on the yacht’s course is produced by
• The Northern Hemisphere parallel matching the Tropic of Cancer has a latitude of:
• About the Automatic Identification System for ships (AIS), choose the answer that is NOT correct
• Time zone 0 has among its features...