chap7answers


Homework Questions – Chapter 76

Homework Questions – Chapter 7

  1. You discover your GPS data is not correct. You are in open water
    away from immediate danger. You find the batteries in your backup unit are dead. Next you try to:

    1. place a Mayday call on channel 16.

    2. use your cell-phone to call the harbor patrol.

    3. backtrack to your last confirmed position.

    4. take bearings on visible marks and plot on your chart.


    Ref: SG Ch 7 – ¶4 Find your Current Location



  2. Upon GPS failure, in addition to compass bearings to determine
    location, there are several alternatives to be considered. Which of the following are NOT recommended?

    1. visual sights on land features.

    2. dead reckoning from last recorded position.

    3. check depth to confirm location on track.

    4. radio authorities to confirm location.


    Ref: WN Chap 12 –pg 146 – Backup Alternatives to find Position



  3. Depth can often be used to confirm your location by:

    1. comparing the depth with that charted for your assumed location.

    2. checking the time of high tide.

    3. verifying the depth of low tide to the time of interest.

    4. checking the depth change from high to low tide.


    Ref: WN Chap 12 – pg 147 – Backup Alternatives, Depth and Depth Profile



  4. Dead Reckoning allows you to determine your likely location by:

    1. estimating direction from your last known location.

    2. calculations using 60D=ST with direction from your last known fix.

    3. using the next waypoint in your GPS.

    4. using seaman’s eye.


    Ref: SG Ch 7 – ¶6 Position by Dead Reckoning



  5. Your GPS has failed. After your likely position is determined, your next action should be

    1. check the battery or fuse to the GPS.

    2. verify the distance to the next waypoint.

    3. calculate your actual speed from the last waypoint.

    4. review any hazards along the route to your next waypoint.


    Ref: WN Chap 12 – pg 147 – Re-Plan Before Proceeding



Answer the next two questions using the figures below

1

2

3

4

  1. When labeling a chart for a Fix the proper symbol to use is

    1. (1)

    2. (2)

    3. (3)

    4. (4)


    Ref: SG Ch 3, Fig 3-1 – Labeling DR Courses



  2. When labeling a chart for a Dead Reckoning position the proper symbol to use is

    1. (1)

    2. (2)

    3. (3)

    4. (4)

    Ref:
    SG Ch 3, ¶ 8,

     Dead
    Reckoning


  3. A reasonable estimate of heading accuracy (including compass accuracy,
    ability to read the compass, sea action on the boat and helmsmanship) is:

    1. +/-2°

    2. +/- 5°

    3. +/- 8°

    4. +/- 10°


    Ref: SG Ch 4 ¶30, & Plotting and Labeling slide 3



  4. When using Dead Reckoning, it is a good idea to occasionally plot your position using bearings, because of:

    1. assumed accuracy of GPS values.

    2. potential errors in charted objects.

    3. adjustments due to chart datum.

    4. cumulative error and external forces.


    Ref: WN Ch 2 – pg 15 Piloting Without Electronics