COXSWAIN NAVIGATION ANSWERS AUS 811-UNDER CONSTRUCTION

 

 

EXERCISE NO.1 SMALL CRAFT

 

1. Why should the weight of the boat be slightly forward of the trailer axle?

To ensure downward pressure on the tow hitch.

 

 

 

2. What problems would occur if your trailer rollers did not spin freely?

Vessel may stick on the trailer.

 

 

 

3. What problems might you have if you back your trailer into the water immediately after a long tow to the slip?

Brake drum/bearings may be hot and fracture.

 

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4. On retrieval, why run out the winch cable before backing the trailer into the water?

 

To ensure its free travel.

 

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5. After winching up you notice that the boat is not straight on the trailer and uneven on all of the rollers. What damage could be caused if you drove away?

 

Point load wear on the vessel.

 

Instability on trailer.


6. Identify the Latitude & Longitude of a position with road access to launch near Wauchope, Telegraph Point and Fernbank Creek. What are the distances to the Breakwall entrance? How long would it take the Duck for the journey? How much fuel would it use?

 

 

 

 

 

_____________NM _________________Hrs ______________Ltrs

 

_____________NM _________________Hrs ______________Ltrs

 

_____________NM _________________Hrs ______________Ltrs

 

 

 

Assume overall top speed of 20Kts and consumption of 40ltrs an hour.

 

 

 

 

 

 

 

 

 

 

EXERCISE NO. 2 BUOYAGE Ask your trainer to explain buoyage then,

 
draw a course from the ocean at A to the upriver wharf at B:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


EXERCISE NO. 3 TIDES - USING THE RULE OF TWELFTHS

Ask your trainer about tides and the Rule of Twelfths.

1. The tide tables give the following data for a place on a particular date:

HW 1450; 1.7 metres LW 2050; 0.5 metres

Find the height of the tide at 1850.

 

2. The tide tables give the following data for a place on a particular date:

LW 1306; 0.3 metres HW 1936; 2.7 metres

At what time will the height of tide be at least 2.5 metres?

 

3. HW 0927; 9.6 metres LW 1533; 2.4 metres

What is the height of the tide at 1130 hours?

 

4. The tide tables give the following data for Sydney (PM Bar + 30 mins).

LW 0740; 0.5 metres HW 1350; 2.3 metres

The sounding of Port Macquarie bar is 3 metres at chart datum. Find the time when the height of the tide is 5 metres.

 

5. A yacht approaching PM at HW on the morning of a certain day, takes a sounding of 8.3 metres. What should be the charted depth?

LW 0058; 0.9 metres

HW 0708; 1.7 metres

LW 1305; 1.0 metres

HW 1915; 1.5 metres

 

Is it springs or neaps?


 

6. The charted depth of a shoal is 2 metres. What would be the clearance beneath the keel of a yacht drawing 1.5 metres at LW if the Tide Tables showed the following information for that particular day

HW 1117; 6.7 metres

LW 1720; 3.1 metres

 

7. A vessel drawing 2.3 meters passes over a reef with a charted depth of 3.1 meters. What would be the underkeel clearance if the height of tide was 1.6 meters?

 

8. At high tide a vessel passes over a bar with a charted depth of 2.6 meters. If the vessel draws 4.1 meters what is the vessels under keel clearance?

HW 0937 1.9m

LW 1514 0.3m

 

9. The tide tables give the following data for Sydney:

LW 0740; 0.5 metres HW 1350; 2.3 metres

Tide at Port Macquarie is 20minutes after Sydney, and 1hr & 50 minutes after at Wauhope. Estimate the time of HW at Rawden Island, Fernbank Creek and Telegraph Point.

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EXERCISE NO. 4 CHART SYMBOLS AND ABBREVIATIONS

Name and Explain the symbols at the following positions on Chart AUS 811

1. 30o 37'.4S 153o 01'.6E

 

2. 31o 28'.6S 152o 56'.3E

 

3. The northern edge of Pt. Korogoro bearing 270o True

Grassy Head(19) is in transit with () Green Island

 

4. The star type symbol at Mermaid Reef

 

5. 31o 39'.9S 152o 52'.4E

 

6. The two cross symbols in close at Queens Head?

 

7. From what points are heights, and, at what datum are soundings measured from on this chart?

 

8. How up to date is the chart you are working on and where could you find the updating corrections?

 

9. Name three nautical publications of use on an inshore passage.

 

 


 

EXERCISE No.5 POSITION - DISTANCE - DIRECTION

1. Identify the following places.

(a) 31o 46'.2S 152o 48'.5E

(b) 30o 56'.4S 153o 06'.1E

(c) 31o 50'.7S 152o 45'.3E

(d) 31o 43'.6S 152o 48'.2E

2. Find the geographical position of the following.

(a) Tacking Point Lt.

(b) Mt. Cairncross (533)

(c) Smokey Cape Lt.

(d) Crescent Hd. (63)

(e) Crowdy Hd. Lt.

3.

Find the distances and true directions between the following positions

FROM TO

(a) Jolly Nose (246) Middle Brother (555)

(b) Croppys Hill (101) Cliff Pk. (99)

(c) Big Smokey (308) Ballengara (308)

(d) 31o 05'.2S 153o 10'.1E 31o 30'.1S 153o 31'.2E

(e) 31o 36'.0S 153o 04'.4E 31o 17'.6S 153o 08'.2E

 


 

4. You are in position 31o 30'.0S 153o 00.'0E

What is the true bearing of:

(a) Tacking Pt. Lt.

(b) Tank (191) on Grants Hd.

(c) Diamond Hd (112)

(d)          Smoky Cape Lt.

 

5.            A vessel is broken down and gives their position as due east of Nobbies Headland in 73 metres.

(a)          What is the Lat/Long position

(b)          How far is the vessel from the entrance to the Hastings River

(c)          How long would it take CR1 to reach the vessel at 20 Knots

 

6. A vessel gives it position as Tacking Point Lighthouse is in transit with North Brother Mountain and Queens Head in transit with the Elephants back

(a)          What is the Lat/Long position

(b)          What is the depth of water

(c)          How far is the vessel from the entrance to the Hastings River

(d)          What course will Rescue Vessel One steer to reach the vessel

(e)          How long would it take R1 to reach the vessel at 20 Knots


 

7. A vessel gives its position as Tacking Point bearing 270 o True and Camden Head bearing 210 o True

(a)  What is the Lat/Long position

(b)  How far is the vessel from Port Macquarie

 

8. A vessel gives its position as Point Plomer bearing 280 o True, Camden Head bearing 220 o True and Tacking Point bearing 235 o True.

What would explain the large cocked hat?

(a)          What is the Lat/Long position

(b)          What is the bearing of the vessel from Port Macquarie

(c)          How far is the vessel from Port Macquarie

 

9. A disabled yacht gives its position as 31 o 20.348 south, 153 o 08.598 east.

(a)          How far is the vessel from Port Macquarie

(b)          What depth of water is the vessel in

(c)          What course should R1 steer to reach the vessel

 

10. R1 has picked up an injured person from a yacht at 31 o 35 S 153 o 01 E. They have called for an Ambulance to meet them at the Country Comfort Wharf at Port Macquarie. Best speed under the conditions is 15 knots.

(a)          What is the ETA of R1 if the time now is 0925

(b)          How long would it take to tow a vessel from the above position at a speed of 7 knots

 

 

11 How far will the R1 travel at:

(a) 23 knots for 5 minutes

(b) 30 knots for 20 minutes

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EXERCISE No.6 DEVIATION AND VARIATION.

1. Complete the table below:

TRUE VARIATION MAGNETIC

2540 100E _________

0480 30W _________

2870 60E _________

1590 20W _________

 

2. Complete the table below:

MAGNETIC VARIATION TRUE

0150 50E _________

1320 70W _________

2460 110W _________

3330 90E _________

 

3. Complete the table below:

TRUE VARIATION MAGNETIC

1460 90E _________

0640 _________ 0730

_________ 90W 3200

2590 _________ 2440

1460 140E _________

_________ 110W 0900


 



TRUE

VARIATION

MAGNETIC

DEVIATION

COMPASS

3500

120E

 

60W

 

1370

90E

 

30E

 

2470

20W

 

30W

 

0030

40W

 

70E

 

 

 

 

 

 

 

 

4. Complete the table below:

 

5. Complete the table below:

TRUE

VARIATION

MAGNETIC

DEVIATION

COMPASS

ERROR

0750

 

0690

20W

 

 

 

170W

 

40E

1210

 

 

 

2430

 

2500

80W

3590

 

 

70E

 

70W

 

80E

 

00E

3210

 

0010

 

0050

 

 

90E

2280

150E

 

 

 

40E

 


EXERCISE NO. 7 RELATIVE BEARINGS

1. A vessel steering 035 oC takes the following bearings.

Crescent Hd. (63) 272 oC

Green Islet. 245 oC

Hat Head. 332 oC

Fix the vessels position.

 

2. A vessel took the following bearings.

NE edge of Scotts Head 291 oC

Smokey Cape Light 250 oC

Hat Head. 213 oC

What is the vessels position if she was steering 170 o C

 

3. A vessel steering 020 oC takes the following bearings with a ships head up un-stabilised display radar.

Tacking Point Light 220 o Rel

NE Edge of Pt. Plomer 291 o Rel

Hastings River 241 o Rel

Fix the vessels position

 

4. A vessel steering a course of 190 oC takes the following radar bearings.

NE edge of Pt. Plomber 93 o Rel

Diamond Hd. (112) 42 o Rel

Tacking Point Light 70 o Rel

Fix the vessels position.


 

EXERCISE No.8 WEATHER INFORMATION

1. Define the following:

(a) trade wind
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(b) pressure gradient
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(c) sea breeze
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(d) strong wind warning
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Before

At the front

After

Wind direction and strength

 

 

 

Barometric Pressure

 

 

 

 

 

Temperature

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Detail the typical weather associated with cold fronts by completing the table.


 

3 Describe:
(a) how an aneroid barometer works.

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(b) how to take a reading from an aneroid barometer.

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4. A Coxswain at sea in inshore coastal areas will have a range of sources of weather information available, some of which will be more reliable or more up to date than others. List these sources in order of importance for reliability or currency.

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DEVIATION CARD 1 NAVIGATION

Magnetic Heading

Deviation

 

Compass Heading

353

7W

000

014

6W

020

035

5W

040

056

4W

060

078

2W

080

099

1W

100

120

0E

120

142

2E

140

164

4E

160

186

6E

180

208

8E

200

230

10E

220

247

7E

240

266

6E

260

283

3E

280

301

1E

300

317

3W

320

336

4W

340

355

5W

360

This table should not to be used for navigation.