Advanced Piloting Course (Coastal

Navigation)

Chapter 3

Fixes

Educational Officer – Dave Westdwest@voyager.net - 651-429-3840

Assistant Educational Officer – David Moberg

davidmoberg@att.net – 715-386-8582 Instructor – Art Mollica

artmollica@usfamily.net - 651-777-0277

United States Power Squadrons®

Any questions on homework from Chapter 1?1. The chart projection used for U.S. coastal areas is: (b) Mercator.

2. An advantage of the Mercator projection is: (c) lines of latitude and longitude are at right angles to each other.

3. When comparing a land mass at a latitude of 70ºN on a Mercator chart with a comparable size land mass near the equator, the: (b) land mass at 70 ºN will appear larger.

4. Polyconic projections are useful especially when traveling over great distances. (b) False

5. As long as a Polyconic chart is limited in extent, the curvature of the grid lines is negligible and the chart is very accurate. (a) True

6. On a Polyconic projection, the parallels of latitude are straight lines. (b) False

7. In planning a cruise, the steering error that can be expected under normal weather conditions is: (b) between 3 º to 5 º.

8. The smaller your boat’s compass, the easier it is to read. (b) False

9. One of the most important advantages of pre-plotting a cruise is that it tells you: (c) areas of hazard to be avoided.

10. When underway in waters near land, it’s best to plot GPS fixes and time every: (c) hour or so.

Any questions on homework from Chapter 1?11. Raster formatted digital charts: (b) have the look and feel of

traditional paper charts.

12. Vector formatted digital charts: (d) are easily stored on chips or cartridges.

13. Digital charts are less accurate than traditional paper charts. (b) False

14. Using the zoom function on a raster digital chart increases the precision of detail. (b) False

15. Chart scale is a factor in determining the accuracy of a digital chart, therefore: (b) a large scale chart covers a small area with great detail.

16. The use of a Chartplotter requires: (d) input from a digital chart to activate the display.

Any questions on homework from Chapter 2?1. Computer-assisted navigation systems are: (b) useful for planning a

cruise in the comfort on one’s home or office.

2. The most accurate radar fix is obtained by: (d) using simultaneous ranges to two or more known points.

3. An electronic bearing line (EBL) lays a line of bearing over a target to: (b) determine the bearing to the target.

4. The variable range marker (VRM) on the radar display screen is used to determine: (c) distance to a target.

5. Range rings on a radar display screen allow the operator to estimate the: (a) distance to a displayed object.

6. According to the rules of relative motion: (b) all fixed objects appear to be moving in the direction opposite from your boat’s motion.

7. According to the rules of relative motion, on a boat’s radar screen when your boat increases speed going forward, all relative motion tends to move toward the bottom of the display screen. (a) True

8. Fixed objects can be differentiated from moving objects on the radar screen by noting which objects appear to be moving: (d) downward on the radar screen in relation to your boat’s course and speed.

Any questions on homework from Chapter 2?9. A “lollypop” displayed on a radar screen is a dashed line to a circle: (b)

indicating a GPS waypoint.

10. A depth sounder, when combined with another navigation tool, can be used to estimate a boat’s position. (a) True

11. The primary purpose of a depth sounder is to: (c) determined water depth below the hull of a boat.

12. Depth sounders can be used to crosscheck the proper functioning of the GPS. (a) True

Slide 6

Visual Bearing Limitations Multiple Bearings

• Simultaneous Bearings Often Difficult

• Landmarks not Separated Sufficiently

• Landmarks too Far Away

• Only one Landmark available

Two Bearings on same Landmark• Sight Landmark from Different Directions

• Second Bearing Somewhat Later

• Called ‘Running Fix’ Advance First Bearing to Current

Position Use Distance Run to Determine How Far

Slide 7

Running Fix

C 285MS 7.5

0935

325M

0935

1012

060M

1012

0935-1012

325M

1012 RFix

C 285MS 7.5

N “3”

Slide 8

Running Fix

C 090MS 7.5

1445

170M

1445

1415

060M

1415

1415

-144

5

060M

1445 RFixC 090MS 7.5

N “9”

C “14”

Slide 9

Running Fix (open ocean) Taught in JN

Charts not available• Create on using

CLS

NavAids not available

Sights on Sun• Morning• Noon• Evening

Advance• Morning to noon• Noon to evening• Evening to morning

Slide 10

Exercise 3 - 1Take out Bowditch Bay Chart. Using two bearings on the same landmark and advance an LOP to plot a Running Fix.At 0900, depart R”2” Fl R 4s Oyster River on a true course of 355. Speed is 6.0 Kn.At 0926, you take a hand bearing compass bearing of 310 on Chapman Point Light.At 0955, you take a second compass bearing of 260 on Chapman Point Light.With these two bearings, plot a running fix.What are the coordinates of the 0955 running fix?Seaman’s Eye: What can you use to confirm the accuracy of the 0955 fix?At 0955, you take up a magnetic heading of 099. You increase your speed to 12 Kn.

T = 355V = 015WM = 010D = 000C = 010

0900 Visual

C

01

0M

S

6.0

D = (ST) / 60D = 6.0x26/60D = 2.6nm

0926

C = 310D = 000M = 310V = 015WT = 295

0926 310M

D = (ST) / 60D = 6.0x29/60D = 2.9nm

0955

C = 260D = 000M = 260V = 015WT = 245

0955

260M

0926-0955 310M0955 RFix

41º 42.7’N72º 01.6’W

You are nearlydue north of

G C”1”,confirming your

position

M = 099V = 015WT = 084

C 099M

S 12.0

Homework Exercise 3-1Running Fix

At 1300, depart from a GPS fix of L 41º 45.0’ N, Lo 71º 55.0’ W on true course of 230º and speed of 6.0kn.

At 1330, take a hand-bearing compass bearing of 318º on “Fl R 6s Horn.”

At 1355, take a hand-bearing compass bearing of 280º on “Chapman Pt “Fl 6s”

Plot 1355 running fix.

What are the coordinates?

L 41º 41.6’ N Lo 72º 01.7’ W

Take up a heading to RW “OR” Mo(A).

1300 GPS

C 245M

S 6.0

1330 318M

1355

280M

1330-1355 318M

1355 RFix

C 175M

S 6.0

1330

1355

0900 Visual

C 0

10

M

S 6

.0

0926

0926 310M

0955

0955

260M

0926-0955 310M

0955 RFix

C 099M

S 12.0

Slide 12

Radar Fix

Compare with Chart• Identifiable features

Distinct Shorelines Isolated Buoys

Plot• Convert Relative Bearings• Distance & Bearing to return echoes

Accuracy• Short Distances (<1/4nm): EBL 55ft; VRM 30ft• Medium Distances (<2nm): EBL 300ft; VRM 75ft• Long Distances (>3nm): EBL 650ft; VRM 200ft

Slide 13

Radar Plotting Board

CPA / TCPA

1004 2.4nm 084º R

1010 1.4nm 064º R

1016 1.0nm 028º R

1/2rr

10041010

1016Modern, high-end radar uses mini-automatic radar plotting aid (MARPA) – allowing you to identify vessel, speed, bearing, closest point of approach and time to closest point of approach.

Slide 14

Radar Images

Buoys are Point Targets• Challenge: Uniquely Identify Buoy

Shoreline Less Defined• Shapes Change with Each Sweep• Only See Forward Slope• Low-lying Areas may not Provide Echoes• Look for Point Features of Shoreline

Look for Prominent Regions• Get Distance from each Feature• Approximate Position Likely

Slide 15

Position by Radar

C 275M

S 7.5

Tim

e

Slide 16

Position by Radar

+

3nmR/R

1 / 2 H – UP

AUTO

M275ºM

EBL 1

VRM 1

245.0º R

01.80 NM

EBL 2

VRM 2

020.0º R

00.00 NM

CURSORBRG 000º

RNG 01.8NM

VRM1

EBL1

EBL2

Slide 17

Position by Radar

+

Slide 18

Position by Radar

C 275M

S 7.5

295M160M

D 1.8

Time Radar

TimeTime

Time

EBL1 245ºR EBL2 020ºR Range 1.8nm

MC 275º RB 245º

520º -360º

MB 160º V 15ºW TB 145º

Slide 19

Exercise 3 – 2 Take out Bowditch Bay Chart.

Using a radar range and a radar bearing on two objects, plot a radar fix.You depart RG “CP” Fl (2+1) R 6s at 0900 on a magnetic heading of 112. Speed is 6.0 Kn.

0900 Visual

C 112MS 6.0

M 122º V 15ºW T 107º

Slide 20

+

3nmR/R

1 / 2 H – UP

AUTO

M112ºM

EBL 1

VRM 1

245.0º R

01.50 NM

EBL 2

VRM 2

000.0º R

00.00 NM

CURSORBRG 000º

RNG 00.0NM

Exercise 3 – 2

At 0950, this is your radar screen image, plot a radar fix.

Slide 21

Exercise 3 – 2 Take out Bowditch Bay Chart.

Using a radar range and a radar bearing on two objects, plot a radar fix.

0900 Visual

C 112MS 6.0 0950 Radar

D 1.5

0950

347M

0950

Homework Exercise 3-2Radar Position

Determine where you are based on the radar screen below.

What are the coordinates of your position?

L 41º 38.7’ N Lo 72º 05.1’ W

Which of the returns are from buoys? Which buoys? RG “CP”

R “16” G “15”

R “4”

G “13”

G “11”

R “

14”

10 9 8 7 6 5 4 3 2 1

10 MINUTE BREAK

PLEASE TAKE YOUR SEATS

Advanced Piloting Course (Coastal

Navigation)

Chapter 4

Avoidance Techniques

Educational Officer – Dave Westdwest@voyager.net - 651-429-3840

Assistant Educational Officer – David Moberg

davidmoberg@att.net – 715-386-8582 Instructor – Art Mollica

artmollica@usfamily.net - 651-777-0277

United States Power Squadrons®

Slide 25

Danger Bearings

VSSPR36VSSPR34

NMT 245M

NLT 070M

Slide 26

Exercise 4-1Danger Bearing

Plot waypoint “TWRN” at Tower R Lt north of Channel Island and “ORRW” at RW “OR” Mo “A”.

At 1000 depart ORRW for TWRN at 7.0kn.

Plot a danger bearing that will keep you west of Channel Island, coming no closer than the 12ft sounding curve.

Take a GPS fix when you reach a point 2.1nm from TWRN and the waypoint bears 037ºM.

From this fix, take up a magnetic heading of 105º and increase speed to 9.0kn.

T = 022 V = 15W M = 037

T = 090 V= 15W M = 105

T = 015 V = 15W M = 030

C

037M

S 7

.0C

105M S 7.0

1058 GPS

1058 – 1000 = 0058 60D = ST D = 7x58/60 D = 6.8

ORRW

TWRN

NLT

030M

1058

D 2

.1

1000

Slide 27

Danger Sector

DANCHI

NM

T 23

5MNLT 250M

Danger

Sector

Slide 28

Crosstrack Error (XTE)

AISI2AISI1

XTE 0.3nm

C 270M0.

6nm

Slide 29

Exercise 4-2 Crosstrack Error

Plot waypoint “BB17” at 41º 38.8’ N 71º 55.0’ W and “BB18” at 41º 38.8’ N 72º 06.7’ W. Using these waypoints as your intended course line plot and label a crosstrack error which will provide a safe passage.

BB17

BB18

T = 270 M = 15W M = 285

C 285M

XTE 1.0

Slide 30

Danger Circle

WFBPS

Slide 31

Exercise 4-3Danger Circle

Using a charted visible object, plot and label a danger circle around the rocks at Rocky Neck Point.

Create a GPS waypoint and plot and label a danger circle around the rocks south of Channel Island.

DCIRD NLT 0.3

DRNPR

D NLT 1.5

Slide 32

Exercise 4-4Radar Avoidance

Plot and label a radar danger circle to avoid the rocky area to the south of Channel Island to ensure you stay at least 0.5 nm away from the rocks as you navigate on a true course of 270º.

D NLT 1.3

0.5

Slide 33

Alarm Zones

Slide 34

Questions ? … Comments

Slide 35

Read Chapters 5 – Student Guide

Do Part I and II of the Weekend Cruise

Next Class – 3 May

Homework