Lesson 3A: Basic Plotting

• AGENDA:– Basic chart features

• Traffic separation scheme• Visual aids• Tabulated depth charts• Scales

– Plotting on a chart

Lesson 3A: Basic Plotting

CHART NOTES, CHARACTERISTICS CHART NOTES, CHARACTERISTICS AND SYMBOLSAND SYMBOLS

Traffic separation Schemes:Traffic separation Schemes: Indicate outbound and inbound Indicate outbound and inbound waterways.waterways.

•Magenta in colorMagenta in color

Traffic Separation Scheme

CHART NOTES, CHARACTERISTICS CHART NOTES, CHARACTERISTICS AND SYMBOLSAND SYMBOLS

Navigation Aids:Navigation Aids:

•Aids with sound and visual Aids with sound and visual characteristics. Listed and labeled on characteristics. Listed and labeled on chart chart

•Usually used as primary navigation Usually used as primary navigation aids for Visual or Radar.aids for Visual or Radar.

Visual Aids’ Characteristics Label

•Notes located throughout the chart Notes located throughout the chart give detailed descriptions of danger, give detailed descriptions of danger, obstructions, depths, overhead obstructions, depths, overhead clearances, etc.clearances, etc.

CHART NOTES, CHART NOTES, CHARACTERISTICS CHARACTERISTICS

AND SYMBOLSAND SYMBOLS

Scale Conversion Tables:Scale Conversion Tables:

•Used for measuring distance (based Used for measuring distance (based on the scale of chart being used).on the scale of chart being used).

•Used for converting U.S. system of Used for converting U.S. system of measurement to metric, etc.measurement to metric, etc.

CHART NOTES, CHART NOTES, CHARACTERISTICS CHARACTERISTICS

AND SYMBOLSAND SYMBOLS

Tabulated Depths

Measuring Distance

NEVER use the longitudescale to determine distanceson a chart.

Navigation Plot: A graphic plot of the movement of a vessel suitably labeled with respect to time, direction, and speed.

TERMS AND DEFINITIONS

CourseCourse – – The direction in The direction in which a vessel is steered or which a vessel is steered or “intended” to be steered. “intended” to be steered.

•Designated as True or Designated as True or Magnetic.Magnetic.

TERMS AND DEFINITIONS

TERMS AND DEFINITIONS

TrackTrack – The path of – The path of intendedintended travel travel

with respect to the earth as drawn on with respect to the earth as drawn on the the

chart.chart.

TERMS AND DEFINITIONS

Speed of Advance (SOA)Speed of Advance (SOA) – The – The speed speed intendedintended to be made good to be made good along the track. along the track.

• The average speed in knots which The average speed in knots which must be maintained during a must be maintained during a passage to arrive at a destination passage to arrive at a destination at an appointed time.at an appointed time.

• Planned track movement based on required SOA

• USS Indianapolis• Indicated every 4 hours• Needed for ALL Voyage

Plans• PIM symbol must be

different from standard navigation symbols.

Ex:

TERMS AND DEFINITIONS

1200Z PIM

PIM-

TERMS AND DEFINITIONS

•Nautical MileNautical Mile – – A unit A unit distance used principally in distance used principally in navigation. 2000 yards equals navigation. 2000 yards equals one Nautical Mile.one Nautical Mile.

•KnotKnot – – A unit of speed equal A unit of speed equal to 1 Nautical Mile per hour.to 1 Nautical Mile per hour.

Distance of 1 NM

1 Degree = 60 NM (Nautical Miles)

1 Minute =1 Nautical Mile

MEASURING DISTANCE

DISTANCE ALWAYS MEASURED ON LATITUDE SCALE!

10 NM10 NM

• View Overall Track (Big Picture) – Use a small scale chart that

encompasses the overall area

• Great Circle Sailing • General (International)

If transiting open ocean

TERMS AND DEFINITIONS

LABELING

1. Visual fix is plotted as a circle.1. Visual fix is plotted as a circle.

2. Electronic fix is plotted as a 2. Electronic fix is plotted as a triangle.triangle.

3. DR is plotted as a half circle.3. DR is plotted as a half circle.

4. EP is plotted as a square.4. EP is plotted as a square.

5. Composite is plotted as a circle 5. Composite is plotted as a circle with a triangle inside the circle.with a triangle inside the circle.

LABELING

6. 6. CourseCourse is labels on top or above the is labels on top or above the track line. Referenced in 3 digits and track line. Referenced in 3 digits and always labeled always labeled “T” for TRUE“T” for TRUE and and “M” “M”

for for MAGNETIC.MAGNETIC.

7. 7. SpeedSpeed is labeled below the trackline is labeled below the trackline and and always expressed in always expressed in KNOTSKNOTS..

8. 8. DR Time is labeled at an angle to the DR Time is labeled at an angle to the track line.track line.

9. 9. Fix Time is labeled in a straight line to Fix Time is labeled in a straight line to the the fix.fix.

COURSE EXAMPLE

   

C-090ºT (080ºM)C-090ºT (080ºM)

  

S-10 KTS S-10 KTS

D-1510 YDSD-1510 YDS

090030 1000

TRACK EXAMPLE

C-090ºT(080ºM)

S-10 KTS D-1510 YDS

0907

00Z

0907

05Z

Plotting Positions on a Nautical Chart

• Step 1 - Examine the latitude scale on side of the chart closest to the desired position.

• Step 2 - Place the metal point of the compass on the reference parallel.

• Step 3 - Spread the compass to reach the desired latitude and make a mark.

MEASURING LAT. & LONG.

•Charted Latitude and Longitudes are Charted Latitude and Longitudes are based on the SCALE of the CHART based on the SCALE of the CHART itself.itself.

Plotting Positions on a Nautical Chart

• Step 4 - Examine the longitude scale on side of the chart closest to the desired position.

• Step 5 - Place the metal point of the compass on the reference meridian.

• Step 6 - Spread the compass to reach the desired longitude and make a mark.

• Step 7 - Locate the reference parallel and meridian intersection and lightly mark the reference parallel with the longitude marked position.

• Step 8 - Without changing the spread of the compass, place the metal point of the compass on the reference meridian.

Plotting Positions on a Nautical Chart

Plotting Positions on a Nautical Chart

• Step 9 - Remeasure latitude on the latitude scale and place the metal end on point and swing a arc so that in crosses the one made for longitude.

• Step 10 - Mark the desired position where the two arcs crossed( intersected) and label the position.

Plotting Positions on a Nautical Chart

24 51.8 E

40 03.9 N

Plotting Positions on different scales of charts.Coastal Chart

Degrees, Minutes and tenths of a Minute

1.5-12

RELATIONSHIP OF TIME/SPEED/DISTANCE

x

D = S x T

T = D / S

S = D / T

RELATIONSHIP OF TIME/SPEED/DISTANCE

D = S x TD = S x TDistance Equals Speed Multiplied By Distance Equals Speed Multiplied By Time.Time.

yds = yds = 12.0 12.0 kt x kt x 33minmin12001200

RELATIONSHIP OF TIME/SPEED/DISTANCE

S = D / TS = D / TSPEED REQUIRED EQUALS DISTANCE SPEED REQUIRED EQUALS DISTANCE DIVIDED BY TIMEDIVIDED BY TIME

kts = kts = 12.0 nm12.0 nm / / 36m36m20.020.0

RELATIONSHIP OF TIME/SPEED/DISTANCE

T = D / ST = D / STIME REQUIRED TO TRAVEL 400NM TIME REQUIRED TO TRAVEL 400NM EQUALS DISTANCE DIVIDED BY EQUALS DISTANCE DIVIDED BY SPEED.SPEED.

= = 1500yds1500yds / / 15.015.0ktskts3 min3 min

PLOT THE FOLLOWING POSITION

• Using chart 12245 plot the following position

• 76º 21’ 36” N• 36º 57’ 50.5” W

• Label as Anchorage 1

DO NOT ERASE THIS MARK!!

QUESTIONS?