Lesson 3A: Basic Plotting

Lesson 3A: Basic Plotting AGENDA: Basic chart features Traffic separation scheme Visual aids Tabulated depth charts Scales Plotting on a chart

CHART NOTES, CHARACTERISTICS AND SYMBOLS Traffic separation Schemes: Indicate outbound and inbound waterways. Magenta in color

Traffic Separation Scheme

CHART NOTES, CHARACTERISTICS AND SYMBOLS Navigation Aids: Aids with sound and visual characteristics. Listed and labeled on chart Usually used as primary navigation aids for Visual or Radar.

Visual Aids’ Characteristics Label

CHART NOTES, CHARACTERISTICS AND SYMBOLS Notes located throughout the chart give detailed descriptions of danger, obstructions, depths, overhead clearances, etc.

CHART NOTES, CHARACTERISTICS AND SYMBOLS Scale Conversion Tables: Used for measuring distance (based on the scale of chart being used). Used for converting U.S. system of measurement to metric, etc.

Tabulated Depths

Measuring Distance NEVER use the longitude scale to determine distances on a chart. Latitude is measured along a meridian and one degree of latitude is essentially the same everywhere on the earth. 1 deg Lat = 60 nm 1 min Lat = 1 nm 1 nm = 2000 yds (actually 6,076 feet) Longitude is measured along parallels of latitude. One degree of longitude will not equal 60 nm except when measured along equator. @ 0° Lat --- 1° = 60 nm @ 30° Lat --- 1° = 52 nm @ 60° Lat --- 1° = 30 nm Speed = 1 knot = 1 nm/hr (1 nm = 1.15 statutory miles)

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

TERMS AND DEFINITIONS Course – The direction in which a vessel is steered or “intended” to be steered. Designated as True or Magnetic.

TERMS AND DEFINITIONS Track – The path of intended travel with respect to the earth as drawn on the chart.

TERMS AND DEFINITIONS Speed of Advance (SOA) – The speed intended to be made good along the track. The average speed in knots which must be maintained during a passage to arrive at a destination at an appointed time.

TERMS AND DEFINITIONS PIM- 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: 1200Z PIM

TERMS AND DEFINITIONS Nautical Mile – A unit distance used principally in navigation. 2000 yards equals one Nautical Mile. Knot – A unit of speed equal to 1 Nautical Mile per hour.

MEASURING DISTANCE Distance of 1 NM 1 Degree = 60 NM (Nautical Miles) 1 Minute = 1 Nautical Mile DISTANCE ALWAYS MEASURED ON LATITUDE SCALE!

10 NM

TERMS AND DEFINITIONS View Overall Track (Big Picture) Use a small scale chart that encompasses the overall area Great Circle Sailing General (International) If transiting open ocean

LABELING 1. Visual fix is plotted as a circle. 2. Electronic fix is plotted as a triangle. 3. DR is plotted as a half circle. 4. EP is plotted as a square. 5. Composite is plotted as a circle with a triangle inside the circle.

LABELING 6.  Course is labels on top or above the track line. Referenced in 3 digits and always labeled “T” for TRUE and “M” for MAGNETIC. 7.  Speed is labeled below the trackline and always expressed in KNOTS. 8.  DR Time is labeled at an angle to the track line. 9.  Fix Time is labeled in a straight line to the fix.

COURSE EXAMPLE C-090ºT (080ºM) S-10 KTS D-1510 YDS 0900 30 1000   C-090ºT (080ºM) S-10 KTS D-1510 YDS 0900 30 1000 Always done in PENCIL

TRACK EXAMPLE C-090ºT(080ºM) S-10 KTS D-1510 YDS 090705Z 090700Z Always in Pencil – never erase a track or fixes until NAVIGATOR says it’s OK

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 based on the SCALE of the CHART 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.

Plotting Positions on a Nautical Chart 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 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

Plotting Positions on different scales of charts. Coastal Chart Degrees, Minutes and tenths of a Minute 40 03.9 N 1.5-12 24 51.8 E

RELATIONSHIP OF TIME/SPEED/DISTANCE D = S x T T = D / S x S = D / T

RELATIONSHIP OF TIME/SPEED/DISTANCE D = S x T Distance Equals Speed Multiplied By Time. yds = 12.0 kt x 3min 1200

RELATIONSHIP OF TIME/SPEED/DISTANCE S = D / T SPEED REQUIRED EQUALS DISTANCE DIVIDED BY TIME kts = 12.0 nm / 36m 20.0

RELATIONSHIP OF TIME/SPEED/DISTANCE T = D / S TIME REQUIRED TO TRAVEL 400NM EQUALS DISTANCE DIVIDED BY SPEED. = 1500yds / 15.0kts 3 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?