Plotting Flashcards
What causes the area of uncertainty?
Currents, wind, human error
What is the area of uncertainty?
Margin of error
What is speed on the water expressed in?
Knots (nautical miles per hour.) 1.15 miles
Why not just use a GPS?
Because batteries die.
How do you measure speed?
With RPMs or speed indicators.
What is a course?
The intended direction of movement through the water.
What different types of courses are there?
True, magnetic, compass
A course can be 000* to -
359*
What is a course line?
The line on a chart which the navigator plots.
What can the course line be labelled in?
True or magnetic
How is a course line written?
Alway drawn from a known fix. Above is the true and magnetic degree, written C080/M060. Under the course line is the speed. Written S 6.0.
What is a heading?
The direction in which a vessel’s bow is pointing.
What is the short form for heading?
hdg
What can a heading be written in?
000* - 359*
What must you remember regarding your hdg?
It is almost always different from your course because of wind and currents.
What is dead reckoning based on?
The True course and the calculated distance travelled through water.
What is DR?
Dead reckoning. They are positions along the course line starting at a fix and showing the position of the boat based on speed and elapsed time
DR positions are plotted at
Regular intervals (every hour), at any change in course or speed, at a bouy.
What is CMG?
Course Made Good. A straight line plot of a vessels travel between adjacent fixes. Obtained by drawing a line directly from one fix to the next.
LOP?
Line Of Position
