ABL-10ABL-10

Piloting andPiloting andNavigationNavigation

Instructor: George Crowl

Requirements (1)Requirements (1)

a. Describe the deck log kept aboard your ship's a. Describe the deck log kept aboard your ship's principal craft. Keep a complete deck log for principal craft. Keep a complete deck log for three cruises.three cruises.

b. Lay a course of at least three legs and b. Lay a course of at least three legs and execute it using dead reckoning.execute it using dead reckoning.

c. Demonstrate your ability to fix your position c. Demonstrate your ability to fix your position by the following methods: taking bearings from by the following methods: taking bearings from two known objects, running fix, and estimated two known objects, running fix, and estimated position.position.

Requirements (2)Requirements (2)

d. Establish distance from a known object by d. Establish distance from a known object by “double the angle on the bow” and explain how “double the angle on the bow” and explain how to set a danger angle.to set a danger angle.

e. Discuss how GPS (Global Positioning e. Discuss how GPS (Global Positioning System) operates and the purpose of waypoints. System) operates and the purpose of waypoints. While underway, demonstrate your ability to While underway, demonstrate your ability to use a GPS while using three different waypoints.use a GPS while using three different waypoints.

f. Discuss the method of establishing a radar f. Discuss the method of establishing a radar fix.fix.

Deck LogsDeck Logs

a. Describe the deck log kept aboard your ship's a. Describe the deck log kept aboard your ship's principal craft. Keep a complete deck log for three principal craft. Keep a complete deck log for three cruises.cruises.

10a. Deck Log10a. Deck Log

Execute Course Using DRExecute Course Using DR

b. Lay a course of at least three legs and execute b. Lay a course of at least three legs and execute it using dead reckoning.it using dead reckoning.

10b. Execute Course Using DR10b. Execute Course Using DR

Plot three legs, totaling about an hour's cruise.Plot three legs, totaling about an hour's cruise. Start and end at identifiable points.Start and end at identifiable points. Use a motor-driven boat. Sailboats under sail Use a motor-driven boat. Sailboats under sail

make this much harder.make this much harder. A closed course, such as 120°M, 360°M, 240°M A closed course, such as 120°M, 360°M, 240°M

is convenient.is convenient. Pay attention to speed and heading.Pay attention to speed and heading. Determine your error at the end.Determine your error at the end.

Fixing MethodsFixing Methods

c. Demonstrate your ability to fix your position by c. Demonstrate your ability to fix your position by the following methods: taking bearings from two the following methods: taking bearings from two known objects, running fix, and estimated known objects, running fix, and estimated position.position.

10c(1). Two-Bearing Fix10c(1). Two-Bearing Fix

Take bearings using a hand-bearing compass.Take bearings using a hand-bearing compass.

Plan a FixPlan a Fix

DR ahead to a good time and place for a fix.DR ahead to a good time and place for a fix. Select someplace with good bearing cuts (90° is Select someplace with good bearing cuts (90° is

ideal, should not be less than 30°).ideal, should not be less than 30°). Select identifiable landmarks (towers, points of Select identifiable landmarks (towers, points of

land, hill tops, etc.)land, hill tops, etc.) Orient yourself so you have the right points.Orient yourself so you have the right points.

Execute the FixExecute the Fix

Two bearings within a minuteTwo bearings within a minute Write the time and bearings down!Write the time and bearings down! Convert to true Convert to true OROR use parallel rules with use parallel rules with

compass circlecompass circle Plot linesPlot lines Crossing point is fixCrossing point is fix

2-LOP Fix (Line of Position)2-LOP Fix (Line of Position)

Take two bearingsTake two bearings Plot mag bearings Plot mag bearings

backwards ORbackwards OR Apply variation Apply variation

backwards and plot true backwards and plot true bearing backwardsbearing backwards

EXERCISE – What do EXERCISE – What do we plot?we plot?

SSPRSSPRp. 27p. 27

3-Bearing Fix3-Bearing Fix

Take 3 mag bearings w/handheld compassTake 3 mag bearings w/handheld compass Convert to true using deck logConvert to true using deck log Plot RECIPROCAL from the actual pointPlot RECIPROCAL from the actual point Triangle is your positionTriangle is your position

10c(2). Running Fix10c(2). Running Fix

Often used to establish distance from an object Often used to establish distance from an object or a shore.or a shore.

May take a long time.May take a long time. Take a bearing. Take a second bearing. Take a bearing. Take a second bearing.

Advance the 1Advance the 1stst bearing to the 2 bearing to the 2ndnd bearing. bearing.

GSxT

Running FixRunning Fix

Take an initial bearing and time, hold course and Take an initial bearing and time, hold course and speed.speed.

Plot initial bearing. Move it along course for Plot initial bearing. Move it along course for amount of time run.amount of time run.

Plot second bearing. WherePlot second bearing. Wherethey cross is fix.they cross is fix.

10c(3). Estimated Position10c(3). Estimated Position

Normal DR position to startNormal DR position to start Add various vectorsAdd various vectors

Current (set / drift)Current (set / drift) Heading / speed error Heading / speed error Single line of position (LOP)Single line of position (LOP)

Set and DriftSet and Drift

Set = direction Set = direction Inbound or outbound tidal flowInbound or outbound tidal flow Ocean current movementOcean current movement

Drift = speedDrift = speed Set – SE, drift 3 K Set ENE, drift 5 KSet – SE, drift 3 K Set ENE, drift 5 K

Estimated Position (EP)Estimated Position (EP)

DR + DR + Set (135°) and Drift (5K)Set (135°) and Drift (5K)

13451345

080° @ 10K080° @ 10K

135° @ 5K135° @ 5K

14451445

14451445Track over groundTrack over ground100° @ 13K100° @ 13K EPEP

Special TechniquesSpecial Techniques

d. Establish distance from a known object by d. Establish distance from a known object by “double the angle on the bow” and explain how to “double the angle on the bow” and explain how to set a danger angle.set a danger angle.

10d(1). Double the Angle on the Bow10d(1). Double the Angle on the Bow

Pick any angle, 15°- 45°. Take first bearing, time.Pick any angle, 15°- 45°. Take first bearing, time. Double it. Take time of 2Double it. Take time of 2ndnd bearing. bearing. Figure distance traveled from GS.Figure distance traveled from GS. 22ndnd bearing angle & time is fix. Distance is bearing angle & time is fix. Distance is

distance traveled from 1distance traveled from 1stst to 2 to 2ndnd bearing. bearing. (Isosceles triangle)(Isosceles triangle)

GSxT

Double the AngleDouble the Angle

Take an angle off the bow (22.5°, 30°, 45°), start Take an angle off the bow (22.5°, 30°, 45°), start a time, hold your course and speed.a time, hold your course and speed.

When you DOUBLE it, stop your time. Calculate When you DOUBLE it, stop your time. Calculate distance run. distance run.

That is the distance to theThat is the distance to theobject, and the angle fromobject, and the angle fromyour heading.your heading.

10d(2). Danger Bearing10d(2). Danger Bearing

Determine the area to avoid.Determine the area to avoid. Plot a line (bearing) that keeps you clear. Plot a line (bearing) that keeps you clear. If you need to stay on the If you need to stay on the LEFTLEFT of the line, keep of the line, keep

your bearing Not Less Than (your bearing Not Less Than (NLTNLT) the bearing.) the bearing. If you need to stay on the If you need to stay on the RIGHTRIGHT of the line, of the line,

keep your bearing Not More Than (keep your bearing Not More Than (NMTNMT). ).

NLT 252M

Set a Danger AngleSet a Danger Angle

Determine how close you can go to the dangerDetermine how close you can go to the danger Read the angle, then set the “danger bearing”Read the angle, then set the “danger bearing” Steer between or Steer between or

beyond the bearing beyond the bearing

SSPRSSPRp. 23p. 23

Global Positioning SystemGlobal Positioning System

e. Discuss how GPS (Global Positioning System) e. Discuss how GPS (Global Positioning System) operates and the purpose of waypoints. While operates and the purpose of waypoints. While underway, demonstrate your ability to use a GPS underway, demonstrate your ability to use a GPS while using three different waypoints.while using three different waypoints.

10e. Global Positioning System (GPS)10e. Global Positioning System (GPS)

Satellites circle the earth at 55° angle to the Satellites circle the earth at 55° angle to the equator.equator.

Everything is precisely timed to provide locationEverything is precisely timed to provide location Lock on four satellites provides 3-D fix.Lock on four satellites provides 3-D fix. Movement over time gives track and Movement over time gives track and

groundspeed.groundspeed.

Global Positioning System (GPS)Global Positioning System (GPS)

Normal GPS operation measures time delaysNormal GPS operation measures time delays

SSPRSSPRp. 30p. 30

WaypointsWaypoints

Waypoints – places you are going along the way!Waypoints – places you are going along the way! Marker 2 to Redfish to HSC 69 …Marker 2 to Redfish to HSC 69 … Coordinates, elevation, description (from list?)Coordinates, elevation, description (from list?) GPS provides steering and calculates time to GPS provides steering and calculates time to

arrival at your current speedarrival at your current speed

002 Mkr 2002 Mkr 2

018 Redfish018 Redfish

069 HSC 69069 HSC 69

Exercise!Exercise!

HandoutHandout CompassCompass GPS Packet (GPS, Quick Start, Instructions)GPS Packet (GPS, Quick Start, Instructions)

We do ded reckoning on land, with a compass We do ded reckoning on land, with a compass and timing our walksand timing our walks

Radar Use and FixingRadar Use and Fixing

f. Discuss the method of establishing a radar fix.f. Discuss the method of establishing a radar fix.

10f. Radar Fixing10f. Radar Fixing

FIRST – the primary purpose of sea-borne radar FIRST – the primary purpose of sea-borne radar is collision avoidance!is collision avoidance!

If a bright spot is getting closer to you and not If a bright spot is getting closer to you and not changing bearing, take avoiding action!changing bearing, take avoiding action!

Radar BearingsRadar Bearings

Range and BearingRange and Bearing

Range and bearing 005°T/2.5NM point of landRange and bearing 005°T/2.5NM point of land Dashed linesDashed lines

Multiple RangesMultiple Ranges

Ranges on nearby land shapesRanges on nearby land shapes Plot using drawing compass arcsPlot using drawing compass arcs

Questions?Questions?

Bonus InformationBonus Information

The information below is not required for The information below is not required for advancement, but is useful for practical point-to-advancement, but is useful for practical point-to-point navigation.point navigation.

Practical Sea Scout NavigationPractical Sea Scout Navigation

Memorize mental speed calculationsMemorize mental speed calculations 4 K, 15 min = 1 NM 4 K, 15 min = 1 NM 5 K, 12 min = 1 NM 5 K, 12 min = 1 NM 6 K, 10 min = 1 NM 6 K, 10 min = 1 NM 30 min = 1/2 your speed30 min = 1/2 your speed 20 min = 1/3 your speed20 min = 1/3 your speed 15 min = 1/4 your speed15 min = 1/4 your speed 12 min = 1/5 your speed12 min = 1/5 your speed 10 min = 1/6 your speed10 min = 1/6 your speed 6 min = 1/10 your speed6 min = 1/10 your speed

Normal NavigationNormal Navigation

Monitor average heading and speedMonitor average heading and speed Calculate ETA to turning pointCalculate ETA to turning point Plan fix about 15-20 minutes short of TPPlan fix about 15-20 minutes short of TP Plot DR for that time for orientationPlot DR for that time for orientation Take fix, plot fix and timeTake fix, plot fix and time

DR Ahead DR Ahead

Measure distance, calculate speedMeasure distance, calculate speed Extend track line from departure through fix, add Extend track line from departure through fix, add

1/10 your speed (speed 4.5K, extend line 1/10 your speed (speed 4.5K, extend line 0.45NM). This is your DR for 6 minutes later.0.45NM). This is your DR for 6 minutes later.

Alter HeadingAlter Heading

Measure course to destination, calculate Measure course to destination, calculate compass heading, tell bosun / skipper to turn at compass heading, tell bosun / skipper to turn at DR time.DR time.

Measure distance, apply speed, calculate ETA, Measure distance, apply speed, calculate ETA, announce it.announce it.

RememberRemember

““The perfect is the enemy of the good.”The perfect is the enemy of the good.” A timely approximate solution is better than a A timely approximate solution is better than a

late perfect solution. late perfect solution. You can continue to modify a timely You can continue to modify a timely

approximation.approximation.

Questions?Questions?