13 Underwayt Homework Q

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UnderwayPractice Cruise Part 2
Homework Q A
Junior Navigation Chapter 13
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The homework for this Chapter consists of
executing a portion of the voyage that you
planned for in Chapter 11. This Practice Cruise
will provide a review of the entire course and
help you prepare for the course exam.
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To complete this cruise, you will need
your Navigators notebook and the completed
homework from Chapter 11 the pilot chart for
July included with your student material the
Excerpts from the Nautical Almanac, contained in
Appendix B of your Student Manual, for all daily
data and Altitude corrections to complete the
sight reductions a copy of any edition of the
Nautical Almanac for the Increments
Corrections tables blank copies of the
Meridian Transit Form included at the end of
Chapter 9 blank copies of the Deck Log
included at the end of this chapter Universal
Plotting Sheets, Sight Reduction forms and CLS
plotting sheets, included with your student
materials.
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Practice Offshore Cruise - Underway
The critical items in your Navigators notebook
related to taking celestial observations are
Height of eye 10.0 ft Index Error (IE) Off
the Arc, 0 01.9 (Check before each
observation) Watch error (WE) f 0-13
seconds This leg of your cruise starts on 29
June 20XX.
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1. As part of your planning, you divided this
voyage into 3 segments (Chapter 11 homework,
Question 2) and planned to plot each voyage
segment on a separate Universal Plotting Sheet
(UPS). You are near the end of the first segment
of the voyage and are about to start the second
voyage segment.
Prepare UPS No. 2, using the Mid-Latitude of
37N and Mid-Longitude of 68 W. From your
voyage plan, you note that the variation in this
area is 15 W. Plot the 15 W isogonic line
using points L1 39 00N, Lo1 69 20W and L2
35 00N, Lo2 66 45W. You also note that
this UPS includes an area where the time zone
changes. Plot the appropriate time zone boundary
on UPS No. 2. You locate two waypoints on
Plotting Sheet No.2 to mark the intended
course for this voyage segment. Plot and label
WP1 at LWP1 38 18.8N, LoWP1 69 14.3W, and
WP2 at LWP2 35 37.5N, LoWP2 67 03.5W.
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Problem 1. Continued from previous slide

• What is the magnetic course along the rhumb
  line of this segment? ______
• b. What should be the planned compass course
  along this rhumb line? ______

162M
Click to view Ships CompassDeviation Table
160
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Deviation Table
Ships Compass Data Compass Magnetic Deviation
000 356 4W 045
043 2W 090 089
1W 135 136 1E 180
183 3E 225 226
1E 270 269 1W 315
313 2W
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2. You transfer data from your Navigators
notebook and review the pilot chart. You note
that your intended route for this segment crosses
two major shipping lanes, Cape Hatteras to Virgin
Rocks and Cape Hatteras to Gibraltar (Chapter 11
homework, 1h). You mark the intersection of the
shipping lanes and your route with WP3 for the
Virgin Rocks route and WP4 for the Gibraltar
route, and check these waypoints in your GPS.
You also make a note in your Navigators notebook
to closely monitor the radar when in the region
of the two waypoints, based on the captains
standing orders regarding radar contacts.
Plot WP3 WP4, as well as the course these
shipping lanes cross your rhumb line course,
on your Plotting Sheet 2. The data recorded
in your Navigators notebook is WP3 L37
50N, Lo 68 20W. Course 058 WP4 L36 40N,
Lo 67 20W. Course 071
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3. 0400. As you begin your watch and start the DR
plot, you note the ships heading, psc, is 133 C
and speed has been 6.8 kn. The GPS indicates a
position of L 3832.6N, Lo 6949.1W. The ships
knotmeter log reading is 0579.0. Conditions
overnight have been Force 3 winds.
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• What is the true DR Course? _______
• b. At 0400, what is the range and bearing to
  waypoint WP1? ________________
• 0428. Received NOAA weather fax logged receipt
  and placed copy in Navigators notebook.

30.6 nm, 117 T
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4. 0800. The GPS indicates a position of L
3825.0N, Lo 6915.8W. The ships heading is
133C and the knotmeter log reading is 0606.1.
Wind is Force 3 with scattered white caps. You
report the position to the captain. Plot the
0800 GPS Fix and DR position, and the CMG from
the 0400 GPS fix on a CLS plotting sheet, using L
3830N and Lo 6930W for the mid-Lat and
mid-Longitude.
a. What has been the true CMG from the 0400 GPS
Fix? _____ b. What has been the speed
through the water (S)? ______ (use the
knotmeter log readings to determine this) c.
What are the 0800 DR coordinates?
___________________ d. What is the set and drift
at 0800? ________________
106
6.8 kn
L38 19.5N, Lo 69 18.8W
Set 023, Dft. 1.5 kn
Click to view 0800 Set Drift CLS Plotting
Sheet Solution
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5. The current has put you off course to the
northeast, so you decide to restart your DR
course from the 0800 GPS fix to WP1, adjusting
for current. Weather and wind conditions have
remained constant so you estimate your speed (S)
will continue to be 6.8 kn for this leg. Draw
a current vector diagram to determine the true
course to allow for the current determined in
Question 4.
Click to view 0800 Current Vector Diagram
a. What is the true course from the 0800 GPS fix
to WP1, not adjusting for current?
_______ b. What is the true course from the 0800
GPS fix to WP1, adjusting for current?
________ c. What is your expected SOA?
_______ d. What is the compass course to WP1,
adjusting for current? ______
169 T
176 T
5.5 kn
188
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6. 0910 You reach WP1 according to your GPS and
change course to WP2, restarting the DR plot. You
check the plotted course line between WP1 and WP2
and confirm it to be 147T. Knotmeter log
reading is 0614.0. You wish to check your
sight-taking accuracy by getting a RFix using an
LOP of the Sun now, and later in the day, a
Meridian Transit of the Sun. At 09-15-15 you
obtain a good observation on the Suns upper
limb and record an hs of 55 59.5. The
knotmeter reading is 0614.6. Reduce this
sight. Use your 0915 DR position as the reference
position. Plot the resultant LOP on a CLS
plotting sheet, using L 38N and Lo 69W for the
mid- Lat and mid-Longitude, and determine the
0915 EP.
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Problem 6. (continued from previous slide)
a. What is your 0915 DR position?
____________________ b. What is Ho?
________ c. What is the intercept?
_____________ d. What is the azimuth? _____ e.
What are the 0915 EP coordinates?
____________________
L3818.3N, Lo6913.9W
55 41.8
4.7 nm Toward
105
Click to view solution onSight Reduction Form
L 3817.1N, Lo 6908.1W
Click to view CLS Plot of 0915 EP
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7. 1000. In preparing to take a Meridian Transit
sight, you want to calculate the time that
transit of the sun will occur. Based on the time
of yesterdays Meridian Transit, you estimate
that Meridian Transit will occur today around ZT
1140. The knotmeter log reads 0620.0. Winds
have increased, waves 1-2 ft. Plot your
expected 1140 DR position on Plotting Sheet 2,
using the boat speed (S) experienced during the
period 0915 - 1000. a. What is your 1140 DR
position? _____________________ b. Using your
1140 DR Lo, what is the calculated time of MT?
____________ 1052. Received NOAA weather
fax logged receipt and placed copy in
Navigators notebook.
L 3803.7N, Lo 6901.8W
ZT 11-39-34
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8. 1130. You prepare to take sights for the
Meridian Transit and start before your calculated
time of MT. You take a run of sights, selecting
the observation on the suns lower limb at WT
11-39-48 with hs of 74 56.1. You note that the
1140 GPS position is L 3803.5N, Lo 6902.1W.
The knotmeter log reads 0632.2, which you use to
calculate your current DR position. Reduce
the sight, using the Meridian Transit Form
contained at the end of Chapter 9.
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Problem 8. (continued from previous slide)
a. What is Ho? _________ b. What is the
calculated latitude from your meridian
transit sight? __________ c. What is the
difference between the calculated latitude
from your MT sight and the latitude given
by the GPS? ________
75 10.6
L 3801.5N
2.0 nm
Click to view solution onMeridian Transit Form
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9. Plot the MT observation on the CLS plotting
sheet you prepared for Question 6. Advance the
0915 Sun LOP for a RFix with the 1140 MT.
a. What are the coordinates of the 1140 RFix?
_______________________ b. What is the
distance between the 1140 GPS fix and the
1140 RFix? _______ With the distance between
the 1140 GPS fix and 1140 RFix small, youre
confident that the GPS is working properly. You
decide to re-start your DR course line from your
next GPS fix.
L 3801.5N, Lo 68 56.4W
4.9 nm
Click to view CLS Plot of 1140 RFix
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10. 1200. The GPS indicates a position of L
3801.0N, Lo 69 00.0W and the knotmeter log
reading is 0634.9.Winds are Force 4 with waves
2-3 ft. After you make your entry in the ships
Deck log and report the position to the captain,
you check on the NOAA radiofax chart issued at
the 1052 weather broadcast. The low pressure
system that you had been following during
previous forecasts, located off the Carolina
coast, is developing faster than expected.
The forecast indicates that the system is on a
course of 035 at a speed of 13 mph and is
predicted to cross L35 00N, Lo75 00W in 24
hours. After conferring with the captain,
you decide to avoid the worst of the system by
changing to a course of 125 T, 90 degrees to the
systems track, and increasing boat speed (S).
Re-start your DR plot from the 1200 GPS
position and locate WP5 150 miles away.
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Problem 10. (continued from previous slide)
a. What is the compass course to WP5?
________ b. What are the coordinates of WP5?
___________________________
139 C
L 3635.0N, Lo 66 25.5W
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Problem 10. (continued from previous slide)
Further evaluation of the weather data
indicates that the system is approximately 200
miles in diameter with winds that could approach
Force 5. You note that the winds will shift from
the SW to S, and then to the SE as the system
passes. You decide to Start logging your
position, either DR or GPS, every two hours
until the weather system passes. Follow the
route from the 1200 fix to WP5. Instruct the
helmsman to follow the route as closely as
possible, but to also follow the wind to
minimize the strain on the boat and crew.
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11. 1400. The knotmeter log reads 0651.9. Winds
are at Force 4 and increasing. Plot the 1400
position on Plotting Sheet 2, and make the
appropriate Deck Log entry.
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12. 1600. The knotmeter log reads 0668.9 and the
GPS position is L 3754.5N, Lo 6817.7W. Winds
have increased to Force 5, waves to 5 ft with
some spray. After plotting and logging the 1600
GPS position you compare the past two log entries
with your plotting sheet. You make note that the
SMG for the past 4 hours has been 8.5 kn.You
note that the 1600 GPS position is NE of the
course line to WP5 this doesnt concern you,
since helmsman was instructed to follow the winds
to minimize the strain on the boat and crew, and
the winds from the storm have been primarily from
the SW. You also note that the 1600 position is
very close to the shipping lane between Cape
Hatteras and Virgin Rock.
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Problem 12. (continued from previous slide)
You immediately have the radar turned ON, and
confirm it is operating and being monitored by
one of the crew. Plot the 1600 GPS position on
Plotting Sheet 2, and make the appropriate Deck
Log entry. a. What is the distance from your
1600 position to where you will cross the Cape
Hatteras to Virgin Rock shipping lane?
_________
4.7 nm
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13. 1614. The radar picks up a large contact at a
range of 25.5 nm, on a bearing of 073T the GPS
position at this time is L3754.2N, Lo6815.4W
and the knotmeter log reads 0670.9. Twenty
minutes later, the GPS indicates your position is
L3753.6N, Lo6811.7W with a knotmeter log
reading of 0673.7 a second radar reading at this
time indicates the contact at a range of 14.9
nm, bearing 076T. Plot this situation on a
CLS plotting sheet, using L 38N and Lo
6810 W for the mid-Latitude and
mid-Longitude.
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Problem 13. (continued from previous slide)
237 (/- 5)
a. What is the ships course? _____________ b.
What is the ships speed? ________________ c.
What time will the ship cross your track?
________________ d. What time will your vessel
cross the ships path? ________________________
24.9 kn (/- 1 kn)
1656 (/- 1 min)
1719 (/- 1 min)
Click to view Ship Crossing CLS Plotting Sheet
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Problem 13. (continued from previous slide)
You note the ships closest point of approach
(CPA) may be within the 4.0 nm limit of the
captains standing orders. e. Should
circumstances require it, what true course
should you be prepared to make?
_______________ f. What would be the compass
course for this action? _____________
057 (/- 5 )
(180 from the ships course)
073 (/- 5)
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Problem 13. (continued from previous slide)
Although there appears to be no need for
avoidance action, you report your position and
intention to the captain. He agrees that no
course change is necessary. 1652. Received
NOAA weather fax logged receipt and placed
copy in Navigators notebook.
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14. 1730. The GPS indicates a position of L
3752.1N, Lo 6801.8W. The knotmeter log reads
0681.7. Winds are F5, with waves 6 ft. The ship
is now well past your position. Checking your
DR plot of the past several hours, you decide to
determine the set and drift indicated by the 1600
GPS fix. You used the 1600 knotmeter log reading
to calculate the speed and distance from the
1200 GPS position, and then plotted the 1600 DR
and the GPS positions on a CLS plotting sheet,
using L 38N and Lo 6830 W for the
mid-Latitude and mid-Longitude.
a. What were the 1600 DR coordinates?
_________________________ b. What was the set at
1600? _____ c. What was the drift at 1600?
______ d. What was the true CMG between 1200 and
1600? _______
L 37 41.5N, Lo 68 24.7W
Click to view1600 Set Drift CLS Plotting Sheet
023
3.5 kn
101
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Problem 14. (continued from previous slide)
You decide to change course to WP2, re-starting
the DR plot from the 1730 GPS position and
accounting for the newly calculated set and
drift. Draw a new current diagram to determine
your new course to steer and expected speed of
advance to WP2.
e. What will be the compass course to steer to
WP2? _________ f. What
will be the speed of advance as you proceed to
WP2? __________
189
5.5 kn
Click to view 1730 Current Vector Diagram
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Problem 14. (continued from previous slide)
You instruct the helmsman to change to this new
course. Due to the winds and sea state, you
continue the 1200 orders to the helmsman to
follow the wind to minimize stress on the boat
and crew. You expect the weather conditions will
continue to set the boat to the NE. You decide to
cover the 1600 to 1730 events by plotting only
the two GPS positions for those times on the UPS
sheet, and inserting a note on the UPS
referencing the previous CLS plotting sheet.
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15. 1800. The knotmeter log reads 0686.0. Winds
have decreased a bit but are still at Force 5 and
waves are running to 4-5 ft. You review the 1642
weather fax and find that the storm is predicted
to pass your present position quickly and that
winds should start to moderate in the next hour.
16. 2000. You record the GPS position of L 37
38.9N, Lo 67 56.0W in the Deck Log and report
this position to the captain. The knotmeter log
reads 0703.0. The winds continue to moderate
slightly and sea conditions improving. Plot
your 2000 GPS position.
17. 2200. The knotmeter reading is 0720.0. Winds
are at F4, with waves at 3-4 ft. Plot your
2200 position.
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18. 2400. You review the Deck Log, making the
2400 entry. You log the GPS position of L
3717.7N, Lo 6746.8W and the knotmeter reading
of 0737.0. Winds have dropped to F3 and
conditions are continuing to improve. You plot
this position on Plotting Sheet 2 and label the
change of date. a. If you were to continue your
watch beyond 2400, what change would need to be
made in the log? ____________________________
_____________
Start a new Deck Log page, with new date.
Having only caught short naps throughout the
storm, you turn over the watch and head to your
berth for a well-earned rest.
Click to view 29 June Deck Log
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Q7
UnderwayPractice Cruise Part 2
End Of Homework Q A
Junior Navigation Chapter 13