Navigation and Ops ISpring 2006

LT Domenic CarlucciNaval ROTC

Rice University

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Lesson 1: Introduction and Piloting Team

• AGENDA:– Types of Marine Navigation– The Bridge Watch Team – Members of the Piloting Team– Navigation Department Organization

• Applicable reading: Hobbs, pp. 3-20.

Types of Navigation

• Piloting (Coastal) Navigation • Dead Reckoning• Celestial Navigation • Radio Navigation• Electronic Navigation

Navigation Defined

• Navigation – The process of safely and efficiently directing

the movements of a vessel from one place to another.

The Bridge Team

• Officer of the Deck (OOD)• Conning Officer• Quartermaster of the Watch (QMOW)• Boatswain’s Mate of the Watch (BMOW)• Lookouts• Helmsman

BearingBearing TakerTaker BearingBearing

TakerTaker

PlotterPlotterBearingBearingRecorderRecorder

NavigatorNavigator

OOD ConningOfficer

Bridge

CIC

PilotingPilotingOfficerOfficer

PlotterPlotter

ChartChart TableTable

ChartChart TableTable

RadarRadar

OperatorOperator

CO

Bridge (Piloting)

• Navigator

• Plotter

• Bearing Taker

• Brg Recorder

CIC (RadNav)

• Piloting Officer

• Radar Operator

• Plotter

The Piloting Team

BearingBearing TakerTaker

BearingBearing TakerTaker

PlotterPlotterBearingBearingRecorderRecorder

NavigatorNavigator

OODOOD ConningConningOfficerOfficer

BridgeBridge

CICCIC

PilotingPilotingOfficerOfficer

PlotterPlotter

ChartChart TableTable

ChartChart TableTable

RadarRadar

OperatorOperator

COCO

“Based on an excellent fix at time :20, Navigation holds us 100 yards left of track. Nearest hazard to navigation is shoal water 500 yards off the port bow. Nearest aid to navigation is red buoy 8, off the stbd beam.

Fathometer reads 45 feet beneath the sonar dome, concurs with charted depth. Distance remaining this leg; 2,500 yards. Next time to turn with be at time :25 to new course 095T. Turn bearing is 272° to Castle Rock.

Navigation recommends coming right to new course 045º to regain track. Set and drift is 270ºT at 1 knot.”

“Combat concurs.”

The Navigator’s Report

Navigation Department Administrative Organization

QM 's, SM 'sm ay a lso in c lu d e ad m in p erson n e l

Navigator Departm ent Heads

Executive OfficerX O

Com m anding OfficerC O

Navigation DepartmentOperational Organization

B earin g TakerB earin g R ecord erP lo tte r

Bridge Team

P ilo tin g O ffice rR ad ar O p era to rP lo tte r

RadNav Team

Navigator

M ain ta in s D eck L ogM ain ta in s N av P lo tW eax O b serva tion s

QM OW

OOD

Com m anding OfficerC O

Questions?

Terrestrial Coordinate System and Nautical Charts

04/18/23

• AGENDA:– Terrestrial Coordinate System (Lat/Long)– Chart Projections– Chart Interpretation/Scale– Chart Correction System– Basic Plotting Techniques

Lesson 2: Terrestrial Coordinate System and Nautical Charts

For navigational purposes, it’s considered a “true” sphere with a circumference of 21,600 NM

Earth: A “not-so-perfect” Sphere

Terrestrial Coordinate System

• Great Circle: The intersection of a plane passing through two points on the surface of the earth and the center of the earth. – Equator– Meridians (longitude)

Prime Meridian (Greenwich, England)

Terrestrial Coordinate System

• Small Circle: : A circle formed from the intersection of a plane not passing through the center of the earth– Parallels (latitude)

Latitude• Latitude - angular distance N/S between the equator and the parallel

of a point. Latitude is measured in degrees of arc from 0 either north or south of the equator.

• Latitude is measured along a meridian• Latitude is always expressed using 2 digits• Abbreviated with “L” • The length of 1 degree of latitude is always 60NM

Longitude• LongitudeLongitude - - angular distance E/W between the prime

meridian and the meridian of a point. Longitude is measured in degrees of arc from 0 to 180 degrees east or west of the prime meridian.

• Longitude is measured along parallels of latitude• Longitude is always expressed using 3 digits• One degree of long does not equal 60 NM unless

measured along the equator• Example of lat/long• Abbreviated using “Lo” or “λ”

• Desirable qualities of a chart projection:– Maintain true shape of physical features.– Maintain correct proportions of features

relative to one another.– True scale, permitting accurate measurement

of distance.

– Rhumb lines plot as straight lines. Lines on the earth’s surface that cross all meridians at the

same angle

– Great circles plot as straight lines.

Chart Projections

Mercator Projection

Mercator Projection©

199

8 G

eoSy

stem

s G

loba

l Cor

pora

tion

Mercator Projection

ADVANTAGES• Position, distance,

and direction can be accurately measured

• True shape of features is maintained over small areas

DISADVANTAGES Distortion of features

increases with distance from the equator

Great circles appear as curved lines

Gnomonic Projection

Gnomonic Projection

ADVANTAGES• Great circles appear

as straight lines• Distortion is minimal

within 1000 nm of point of tangency

DISADVANTAGES Rhumb lines appear as

curved lines Distance and direction

cannot be measured accurately

True shape is not presented

Mercator vs. Gnomonic

Mercator Gnomonic

Parallels: Straight lines Curved (except equator)

Meridians: Straight Straight

Conformal: YES NO

Great Circles: Curved* Straight

Rhumb lines: Straight Curved lines

Applications: Piloting Great-circle determination(Distance measurement)

* Except meridians

Chart Projection Summary

Chart Production

• Two government agencies are mainly responsible for producing nautical charts - the Defense Mapping Agency (formerly NIMA) and the National Ocean Service.– Defense Mapping Agency (DMA) - concerned mainly with the

production and upkeep of charts and related navigational publications covering all ocean areas of the world outside U.S. territorial waters.

– NOAA/National Ocean Service - concerned with charts covering

inland and coastal waters of the United States and its possessions.

Chart Numbering System

• All charts produced by DMA and NOS are assigned a number from one to five digits, according to the scale and area they depict.

# of digits Scale 1 No scale involved (supporting pub) 2 1 : 9,000,001 and smaller 3 1 : 2,000,001 to 1 :1,900,000 4 Miscellaneous and special, non-navigational charts 5 1 : 2,000,000 and larger

• The chart numbering system also allows the navigator to organize his/her charts into portfolios.

Ocean Basins

Costal Regions

Chart Inventory

• What charts do you carry onboard?– All charts for regions you anticipate

operating in– Portfolios -

55 total– 20-30 for Destroyer/Large Deck

– even less for Merchant Ship

Chart Corrections

• Navigation data changes frequently– Submerged wrecks, buoys get moved, etc

• Notice to Mariners and Local Notice to Mariners – Pamphlet mailed to ships– QMs make changes to the charts they need– NTMs are kept on file

Plotting a Position

• Determine the parallels on the chart that bracket the latitude.• Place the pivot point of the compass on the closest line.• Spread the compass until the lead rests on the given latitude.• Move to the approximate longitude and swing an arc.

Plotting a Position

• The same process is repeated using the longitude scale and the given longitude.

• The desired position is the intersection of these two arcs.• If plotted correctly, the intersection should occur at the crest of

both arcs.

Measuring Distance

• The latitude scale can be used to measure distances, The latitude scale can be used to measure distances, since one degree of latitude equals 60 nautical miles, since one degree of latitude equals 60 nautical miles, everywhere on the earth.everywhere on the earth.

Measuring Distance

NEVER use the longitudescale to determine distanceson a chart.

Measuring Direction

• All rhumb lines on a Mercator projection All rhumb lines on a Mercator projection represent represent truetrue directions. directions.

• Measurement of direction on Measurement of direction on a Mercator chart is a Mercator chart is accomplished by using a accomplished by using a parallel rulerparallel ruler to transfer the to transfer the direction of a rhumb line to direction of a rhumb line to a nearby compass rose.a nearby compass rose.

Measuring Direction

• A

• B

Review

• What is a great circle? Name two important ones?

• How are latitudes measured? Longitude?• What is the best projection for marine

navigation?• What does large scale mean?• How many miles per degree of latitude?

Study Questions

• Nav Workbook Ch 3– 12, 13

• Nav Workbook Ch 4– Sec 1: 2-4, 6, 7, 9– Sec 2: 2-6, 13– Sec 3: 1,2