105.1 Navigation, Piloting and Charts Flashcards
In measuring distances, what concern should you have if you have two or more charts laid out in front of you?
- They may have different overall scales (1:6000 vs. 1:60,000)
- They may not all have the longitude scale on the right or left depending on how the physical chart is laid out on the table.
If a set of calipers cannot span the distance to be measured, one should:
Set the calipers to a fixed distance on the the longitude scale (say, 10 min = 10 miles) and then “walk” the calipers across the distance, counting steps. Then measure residual amount.
The scale of a large area Sailing Chart would be characterized as ____ scale.
small
Relate the inner magnetic degree circle on a rose chart to the boat’s _____ _____.
magnetic compass
“Coastal Navigation”
within sight of lands
Chart books
Collection of charts for an area
A “small scale” chart has a ______ number for X in the 1:X
large e.g., 600,000, shows a large area
A “medium scale” chart has a ______ number for X in the 1:X
mid-sized, e.g., 60,000
A General chart is _____ scale.
“Small scale” (so large portion of coast; 1:600,000)
In an emergency situation, report your position as _____, _____, and ______.
a direction (state magnetic or true), a distance, from something (e.g., 195 degrees magnetic, 7.6 miles, FROM lighthouse)
Direction is expressed in ______, starting from ____ for north around to _____ for north again
degrees, 0; 360
A nautical mile is _____ feet, versus a statute or land mile of ____ feet.
6076, 5280
A nautical mile cannot be measured along the latitude scale at the top or bottom of the chart since….
one minute of measurement means a different physical distance at different latitudes.
Two means of plotting a position on a chart
- GPS coordinates
2. Direction and distance from known points (landmarks, buoys, etc.)
“Navigation”
use of visual observations and charts
know current location
plan movement of boat from A to B
Some common errors when plotting: Parallel rulers _____; reading degrees from the ____ rose; misreading _____ numbers; misreading the ____ scale
slip; outer; degree; mileage
Two principles measurements uses of direction –
Course and Bearing
“Piloting”
directing safe passage
restricted/dangerous waters
CONTINUOUS reference to landmarks, bouys, soundings
“Celestial Navigation”
use of sun, moon, planets and stars
A Harbor Chart is _____ scale.
“Large scale”
A Coastal Chart is ____ scale.
“Medium to large scale” (so along shore, into major bays/harbors; 1:60,000)
One nautical mile is exactly one _____ of measurement along the ______ scale, which can be found on the left or right of any north oriented chart.
minute, longitudinal
A great name for a boat is
HABU HABU
“Knot”
nautical miles per hour (you don’t say “knots per hour”)
A magnetic course or bearing to 30 degrees should be abbreviated as
C030M (course, direction/bearing,magnetic)
A “large scale” chart has a _____ number for X in the 1:X
small e.g., 6,000, shows a small area
When plotting a location, it is wise to treat it like cutting lumber
Do all measurements twice before using
To determine direction, start at the _____ of the magnetic rose and then outward in either of ____ directions
center, two
In anything nautical, a “mile” means a
nautical mile
A Sailing chart is used for ____-____ voyages.
trans-ocean
Difference between magnetic rose and the geographic or true rose is called
variation
Cruising guides
Useful for particular harbors
