02- Fundamentals of Plotting Flashcards
1
Q
Line of Position
A
- A line along which the navigator known he or she is located
- Minimum of three LOPs are needed for a fix
2
Q
Two means of LOPs
A
- Visual
- RADAR
3
Q
Visual LOPs
A
- Bearing of a known, fixed object through the use of pelorus or gyro repeater
- Represented by a straight line towards a fixed object
- Labeled with the time (mandatory) and direction (optional)
- Line being drawn is the reciprocal of the bearing you take on the object since you are drawing it from the object rather than to it.
4
Q
RADAR LOPs
A
- Represented by an arc centered on teh object (RADAR NAVAID)
- Always read from the leading edge of the object
5
Q
Visual NAVAIDS
A
Yellow Circle
- Labeled V_
- Fixed object used to obtain a visual LOP (bearing)
- Buoys cannot be used to obtain an LOP
- Must be easily identifiable and marked on the natutical chart
- Choose objects that will yield bearings that are widely spread
6
Q
RADAR NAVAIDS
A
Blue Triangles
- Labeled R_
- Points of coast contour (easily ID’d on the chart)
- Examples
- Lights
- Piers
- Daymarkers
- Bends on shore
7
Q
Fixes order for obtaining LOPs
A
- Visual “Beam to Bow”
- Should not shoot anything astern of the ship.
- RADAR “Bow to Beam”
- Can shoot any RADAR aids in range, regardless or position to ship
8
Q
Optimum spread for LOPs
A
- 120º
- If on the same side, 60º
9
Q
A
Visual Fix
- All visual LOPs used in obtaining fix
10
Q
A
Electronic or Composite
- At least one electronic means used
11
Q
A
Dead Reckoning
- DR position; Based on previous fix on ordered course and speed
12
Q
A
Estimated Position
- Most probable position of ship based on set and draft
13
Q
Frequency of fixes <2 nm from land/shoal
A
3 min
14
Q
Frequency of fixes 2-10 nm from land/shoal
A
3-15 min as conditions allows
15
Q
Frequency of fixes 10-30 nm
A
15-30 min as conditions allows
