Sailing Navigation 1
Given a chart, the _ are parallel to the equator.
Latitudes.
Fixing a _ cordinate defines a meridian.
Latitude.
_ is measured North or South, and ranges from _ degrees (the Equator) to _ degrees (the Poles).
Latitude, 0, 90.
_ is measured East or West, and ranges from _ degrees (Greenwich Meridian) to _ degrees.
Longitude, 0, 180.
Which of the following are correct notations for xxxx N.
- 49 deg 52.3 min
- 23 def 51 min 6 min
1 deg is equal to _ min.
49 deg 50.3 min is the same as 49 deg 50 min 18 sec.
49 degrees + 50 + 0.3 x60 mins
50.4' is the same as 50'24''.
True
52'44'7 means 52 mins, 44.7 mins
True
What is the difference betwee 12.4' and 12,4'?
They are the same.
Distances can be measured using both latitude and longitudes on the chart.
False - only latitudes can be used.
What is the chart heading for going directly south?
Someone tells you the coordinates are xxx, yyy. xxx is the _(latitude/longitude).
Latitude.
Someone measured degrees from the left of the map. That measurement is the _.
Latitude (See Position and Distance chapter Fig 8).
The generally used Mercetor project preserves _.
Angles.
What is a great circle?
A great circle is any circle on the globe whose circumference is maximum. The equator and circles joined by meridians are examples.
A is sailing from South Africa to Brazil. Will she cross each meridian at the same angle? Could she cross multiple meridians at the same angle?
She will most likely cross each meridian at different angles, unless she sails on the equator or a meridian. (See Position and Distance chapter Fig 5,6).
On the map, dotted lines at sea mean the depth is _.
On the map, dashed lines at sea mean the depth is _.
Dashed lines - 10m.
How many meters is one nautical mile?
1852 m.
One nautical mile is equal to _ of _.
1 min of latitude (See Position and Distance chapter Fig 7).
How many cables is 1 nautical mile?
10
One degree of longitude is around _ nautical miles at the Equator and _ at the poles.
Travelling for 1 hour at 1 knot covers a distance of _ nautical miles.
The following symbol means _.
Underwater rock, depth unknown.
The following symbol means _.
Underwater rock.
The following symbol means _.
Shipwreck.
The following number on means _.
5.6 m (Some picture of the depth on a chart).
Recall the cardinal symbols for North, East, South, and West. How arer they on the map, and how are they in real life? What does this sign mean?
(List the mnemonic by Vera, and how the arrows correspond to the actual pole).
Symbols
T: Rock under sea level.
Upside down T: RockRock above sea level.
+ : Rock awash - barely above sea level, barely visible.
cairns.
Ligthouses.
Sector lights
Leading lights.
On the green pathways: Red dot (port), Green dot (starboard) when going to the harbour.
+ with dots on each corner: Group of rocks.
Isolated danger.
(See also links in slide 85 of first lecture).
What is the difference between port and starboard?
Starboard is the rightside when facing towards the hull of the boat.
Sector lights are visible at night.
False
What does the text F1(4)W.15s54m20M mean when it is next to a lighthouse?
The light characteristic - (4) number of times it blinks, 15s is period of the flash (how long one flash takes) - W for white light, and rest is how far it is visible.
What is the difference between the True North and the Magnetic North?
The True North is the is the North pointing towards the North pole on the chart and is always fixed, while the Magnetic North is where a magnetic compass points towards, and depends on the time and location it is measured.
What does the variation refer to?
The difference between the direction of the True North and the Magnetic North.
Variation depends only on the location.
False, it also changes over time.
Name one thing that can affect the measurement from a magnetic compass.
Electical devices on board.
What is the difference between variation and deviation, and how are they related? #DOUBT
Variation depends more on global properties like location and time of the vessel, thus two vessels relatively closeby may use the same variation value. Deviation on the other hand depends more on local properties like the electronic devices on the vessel etc. thus two vessels relatively closeby may have different deviation values.
The difference between the compass angle and the true angle equals the variation and deviation.
On motordriven boats, how do you give way?
On sailboats, how do you give way?
The one sailing on a side wind (has more maneovarability) has to give way. Given two boats going north, and wind coming from north, the boat for which wind is coming from startboard has the right of way.
If you have the right of way, can you let the other boat go first?
Yes, but you need to do so well in advance and let the other boat know ahead of time.
When using compasses, what are the 3 different headings, and how do they relate to each other?
- True heading, we get it from the chart
- Magnetic heading, it points towards the magnetic north.
Compass heading, it shows the magnetic north up to deviation, and is what we see on the boat.
Compass heading Deviation Magnetic heading Variation True heading
Symbols
TODO List all symbols for restrictions and mandatory instructions.
In the speeding limit symbols, the speed is in which units?
km/h
How fast is 9km/h approximately in knots?
9km/h ~ 5knots
Give the formulas for speed (S) given distance (D) and time (T), similarly D given S,T and T given S,D.
Name some landmarks used for fixing your position.
- Pairs of buoys.
- Pair of leading lights.
What do the direction of the light lobes mean?
For the lateral marks, they are visible on all sides so the lobes on the chart do not indicate direction, however the lobes for leading lights on the charts indicate the direction of their lights.
When using handbearing compasses, which heading do we get?
We assume 0 deviation since we do not have a deviation table for them, thus the compass heading and magnetic heading is the same.
Sound signals.
TODO When turning to starboard : 1 short blast. (See slide for extra information).
When turning to port : 2 short blasts.
Asking for permisison to pass, and answering the question.
Warning and asnwering to the warning.
Informing about the state of the vessel when visibility is reduced.
Using engine in reverse : 3 beeps.
Heavy fog : 1 beep/minute.
Daymarks
Vessel not under command : 2 circles.
Not aground : 3 circles.
Sailing under power : Upside down triangle.
Restricted in ability to maneouvre.
Which colours must be lit at night.
Green on starboard, red on port, white in the middle if it is a powerdriven vessel.
Navigation lights of vessels restricted
TODO Get from slides
Describe how high and low pressure regions form.
Winds caused by high pressure areas are weaker.
True - on the other hand circular winds from low pressure areas are very clear.
Describe the funnel effect.
In narrow channels, the wind is intensified. When wind comes perpedendicular to the channel, it could split into both directions defined by the channel.
Distress signals.
Press the red button for 6 seconds.
Waving both hands up and down.
Red flares. (Police/authorities use white flares as a stop command).
SOS (. . . _ _ _ . . .) via horns.
Orange smoke signal.
EPIRB
N or C flags.
Flame on board.
Colouring the water red.
Describe the traffic separation scheme.
Sailing boats must cross perpedincular to the separation scheme passage #TOOD Find actual names for them.
When crossing perpendicularly, sailing against the sidewind actually increases the distance travelled by the boat. #TODO Understand this a bit more.
Harbour symbols
Visibility limits
#TODO Get the values in nM miles from the slides.
Lighthouses
Leading lights
Ice buoy
Stake bouys
How are restricted areas designated (in Finland)?
Continuous line of purple T's.
Can you anchor in restricted areas (in Finland)?
Yes, as long as you are more than 100m away from the nearest coast.
Can you be closer than 100m from a restricted area (in Finland)?
Yes, when you are in a waterway you can do so without a permission. #TODO See also slide on Restricted Area.