Course Plottingand Labelling Standards Plotting and Labeling... · Course Plottingand Labelling Standards Canadian Power & Sail Squadrons| 1st edition 2005 Revised 2007, 2008

Course Plotting and

Labelling StandardsCanadian Power & Sail Squadrons | 1st edition 2005

Revised 2007, 2008

CPS Course Plotting and Labelling Standards

Published by Canadian Power & Sail Squadrons

Escadrilles canadiennes de plaisance

Toronto, Ontario

1st Edition © Canadian Power & Sail Squadrons 2005, Revised 2007, 2008

All rights reserved. No part of this publication may be reproduced, stored in a

retrieval system, or transmitted in any form, or by any means—electronic,

mechanical photocopying, recording, or otherwise—without the written per-

mission of Canadian Power & Sail Squadrons.

Canadian Power & Sail Squadrons

26 Golden Gate Court

Toronto, Ontario M1P 3A5

Canada

Phone: 416-293-2438 in the Greater Toronto Area

1-888-CPS-BOAT (1-888-277-2628) in all other areas

Internet: www.cps-ecp.ca

Printed in Canada

Funding for this manual provided by the CPS Foundation.

ISBN: ISBN 978-0-9780968-5-4

Ta b l e o f c o n t e n t s

1.0 Introduction to plotting ______________________________________________ 11.1 Reasons for plotting1.2 Labelling1.3 General instructions1.4 Standards of accuracy1.5 Rules for rounding1.6 Conventions used in this manual

1.6.1 Use of capital letters in text1.6.2 Abbreviations and terms

2.0 Lines of motion ______________________________________________________ 42.1 Track (TR)2.2 Course (C)2.3 Track made good (TMG)

3.0 Lines of position (LOPs)________________________________________________ 53.1 Range

3.1.1 Plotting ranges3.2 Bearings and lines of position (LOPs)

3.2.1 Plotting bearings3.2.2 Electronic bearings3.2.3 Advanced LOP

3.3 Circle of position (COP)3.3.1 COP using a vertical angle3.3.2 COP using a horizontal angle3.3.3 COP using electronic equipment3.3.4 Advanced COP

4.0 Boat positions ________________________________________________________ 94.1 Dead reckoning (DR) position 4.2 Fixes

4.2.1 Close aboard fix4.2.2 Two-bearing fix4.2.3 LOP and COP fix4.2.4 Two COP fix4.2.5 Three-bearing fix4.2.6 Horizontal angle fix4.2.7 Electronic fixes

4.3 Running fixes4.3.1 Single object running fix4.3.2 Advanced LOP running fix4.3.3 Advanced COP running fix

4.4 Estimated position (EP)


4.4.1 EP without current4.4.2 EP with current

5.0 Standing clear of danger ____________________________________________ 145.1 Danger angles

5.1.1 Vertical danger angles5.1.2 Horizontal danger angles

5.2 Danger bearings

6.0 Vectors used in current problems______________________________________ 166.1 Course to steer6.2 Track or track made good6.3 Current6.4 Current vector diagrams6.5 Current from a DR plot

7.0 Celestial navigation __________________________________________________ 187.1 Celestial lines of position

7.1.1 Azimuth line7.1.2 Celestial line of position

7.2 Celestial fixes7.2.1 Simultaneous sights7.2.2 Running fix

7.3 Estimated position (EP)7.3.1 EP without current7.3.2 EP with current

7.4 Miscellaneous plotting7.4.1 Time zone crossing7.4.2 Variation changes

8.0 Deck log __________________________________________________________ 238.1 Deck log for sample cruise8.2 Sample cruise plot on chart (see centrefold)


CPS Course Plotting and Labelling Standards 1

Plotting is the art and science of recording naviga-tional data on a marine chart. The actual act ofplotting consists of accurately drawing variouskinds of lines and symbols on a chart and labellingthem correctly. This includes such data as:

• the lines showing where the boat is going orhas been;

• the lines necessary to determine the positionof the boat;

• the actual or estimated future position of the boat; and

• information needed to avoid danger.

This manual illustrates the minimum chart plot-ting and labelling standards used by CPS-ECP.Additional information may be added if needed.The mechanics of obtaining and plotting bear-ings, circular lines of position, current vectordiagrams, etc. are taught in various CPS-ECP cours-es. The examples used in this manual show thefinal result when plotting and labelling the navi-gational observations made while piloting a boat.

1.1 Reasons for plotting

Cruise planning requires plotting on a chartbecause it allows the skipper to answer a number of important questions, such as:

• What is the distance to the destination?

• How long will it take?

• When will I arrive?

• How much fuel will be required to completethe trip?

• What is the compass course to steer?

• Are there any underwater hazards (rocks,kelp beds, etc.) along the route?

• Where are the nearby safe harbours to use incase of bad weather?

Plotting cruises provides a plan for others to follow if something happens to the skipper. Theplot can provide position information in case ofan accident or grounding. The plot can also beused if the trip is to be repeated, or given toanother skipper for information.

Perhaps more importantly, plotting on papercharts is a positive backup for electronic naviga-tion. It is very tempting to rely completely onelectronics, such as GPS or chart plotters, andneglect manual plotting. Electronics can fail andplots on a paper chart will enable the skipper tosafely navigate, even in adverse weather.

The plotting and labelling standards included inthis manual have been adopted by the TrainingDepartment of CPS-ECP and apply to all courses.This ensures the Advanced Course student willnot need to learn different standards as addi-tional courses are taken. These standards providea consistent basis for evaluating student home-work and exam answers. The standards also fur-nish a good foundation that can be used over alifetime of cruising.

Lastly, many people find plotting and the exten-sive use of charts to be a lot of fun and theyenjoy doing it.

1.2 Labelling

The labelling aspect of plotting is as importantas the accurate drawing of lines. Consistency inplotting allows anyone to understand the plotand will even allow them to take over the safenavigation of the vessel if need be. Lines with-out labels are confusing and useless after a short

1.0 Introduction to plotting

2 CPS Course Plotting and Labelling Standards

period of time, even to those who drew them.Without labels the crew will likely be confused ifcalled upon in an emergency, either to give aposition to the Coast Guard, or to bring the boatto a safe harbour under adverse conditions.

1.3 General instructions

Broadly speaking, there are three ways torecord plotting concepts:

1 Fully written descriptions, such as ‘deadreckoning position’, ‘line of position’, or‘Global Positioning System’, are used in textmaterial or glossaries.

2 Letter abbreviations for the written descrip-tion, such as ‘DR’, ‘LOP’, or ‘GPS’, are used in log books and text material.

3 Symbols are used to represent the written orabbreviated description, such as a circle for fixor a triangle for a predetermined waypoint.

Generally the use of both a symbol and letterabbreviations on the chart is considered redun-dant, and is not necessary unless both are need-ed to eliminate confusion. The use of a symbolalone also helps to reduce clutter when workingin a congested area on a chart.

Capital letters are used for all labels when charting.All labelling should be done so the lettering can beread from the bottom or right-hand side of thechart. In other words, all lines, except lines runningdue north or south, are labelled with the mostimportant information on the north side of theline. Lines running due north or south are labelledwith the most important information on the westside of the line. Direction is the most importantinformation for lines showing boat movement.Time is the most important information for linesdetermining the boat position. This informationwill automatically be placed on the correct side ofthe line when it is written down before the plotteris moved.


Circular lines of position are labelled so that thetime is located on the north side of the arc.

In areas where it is not possible to follow thisstandard because of extensive chart detail, thelabels can be placed in a clear place on the chartwith an S-shaped arrow pointing at the location.

Lines of motion (e.g., track, course) are drawnas solid lines.

A Line of Position (LOP) is a line on which a boatis located, and is used to establish a fix. Theselines should be of sufficient length to eliminateconfusion in identifying the charted object usedfor the bearing. Boating students should drawthese lines up to, but not through any aids tonavigation. More advanced students may useshorter LOPs. A dashed line is used for any por-tion of an LOP on which a boat cannot be posi-tioned (e.g., an LOP plotted over land), or for aconstruction line.

Directions are always labelled with three digits;e.g., east is written as 090. The time of an eventis always labelled with four digits; e.g., 6 o’clockin the morning is written as 0600. Speed isalways labelled to the nearest tenth of a knot;e.g., 6.5 knots, 12.0 knots, etc.

1.4 Standards of accuracy

The purpose of this manual is to illustrate, byexample, the standardized method of plottingused in CPS courses. The details of how the datato plot are derived will be found in the coursetexts. CPS standards of accuracy for plotting andrecording data:

Latitude..........................nearest 0.1 minuteLongitude.......................nearest 0.1 minuteTime (24-hour clock)......nearest minute (four

digits)Speed..............................nearest 0.1 knotDistance..........................nearest 0.1 nautical mileTrack or course...............nearest degree (three

digits)Variation or deviation...nearest degreeBearing...........................nearest degree (three

digits)Current set .....................nearest degree (three

digits)Current drift...................nearest 0.1 knotHeight of tide ................nearest 0.1 metre or

0.1 foot


1.5 Rules for rounding

When a figure is to be rounded off to fewerplaces of decimals, the procedure is as follows:(a) If the decimal to be rounded off is 4 or

lower, it is dropped.Example: 3.432 rounded to two places is3.43, rounded to one place is 3.4.

(b) If the decimal to be rounded off is 5 or high-er, the preceding digit is raised to the nexthigher value and the rounded digit isdropped.Example: 4.356 rounded to two places is4.36, rounded to one place is 4.4.

Greater accuracy is achieved if rounding takesplace after the completion of addition, multipli-cation, etc.

1.6 Conventions used in this manual

1.6.1 Use of capital letters in text

Small capitals or uppercase letters are used toidentify how various terms are used in this man-ual. Normal capitalization rules are used in thetext except to identify specific uses for theterms used on the chart or abbreviations.

• Uppercase letters enclosed in single quotesidentify terms to be used on the chart; e.g.,‘TR’, ‘FIX’, etc.

• Small capitals are used to identify abbrevia-tions; e.g., LOP, DR, GPS, etc.

1.6.2 Abbreviations and terms

The following abbreviations are found in thetext, graphics or deck log of this manual:

Brg ...............................bearingC...................................course to be steeredC Brg............................compass bearingCOP..............................circle of positionCrs chg.........................course changeDep..............................departureDFT ..............................current speedDR................................dead reckoning positionEP.................................estimated positionFIX................................known location of boatGPS ..............................global position systemHC Brg .........................hand compass bearingHdg..............................heading of boatKn ................................knot, a unit of speedLOP ..............................line of positionNLT...............................not less thanNMT.............................not more thanRAD .............................radarR Brg............................relative bearingRFIX .............................running fixS ...................................boat speed through waterSET ...............................current directionSMG.............................speed made goodSOA..............................speed of advanceStbd .............................starboardTR.................................trackTMG.............................Track made goodVAR E...........................east variationVAR W.........................west variationWP ...............................waypointZD ................................time zone description


2.0 Lines of motionThe symbols in this section are used to indicate thedirection and speed of a boat. All directions are drawnand labelled with respect to true north but labelledwith both true and magnetic values (e.g.: C 120/100M).A standard variation of 20° East is used in this manual.

2.1 Track (TR)

Track is a line on the chart showing the intended pathof a boat over the ground. It is labelled on the northside of the line with the symbol ‘TR’ and the true/mag-netic direction. The speed of advance is placed on thesouth true side of the line with the symbol ‘SOA’ andthe speed.

2.2 Course (C)

Course is a line on the chart showing the direction aboat is to be steered. It is labelled on the north side ofthe line with the symbol ‘C’ and the true/magnetic direc-tion. The speed of the boat through the water is placedon the south side of the line, prefixed with the symbol ‘S’.

2.3 Track made good (TMG)

Track made good is the direction the boat travelledbetween two fixes. It is drawn between two fixes andlabelled on the north side of the line with the symbol‘TMG’ and true/magnetic direction. The speed madegood is placed on the south side of the line with thesymbol ‘SMG’ and the speed.


3.0 Lines of position (LOPs)A bearing is the direction of an object as seen from aboat. A true bearing, measured in degrees from truenorth, but labelled with both true and magnetic values(e.g.: 120/100M), is used to plot a line of position (LOP)on a chart. LOPs can also be obtained from ranges,compass bearings or bearings obtained by electronicmeans such as GPS or radar. Under certain circum-stances the LOP may be advanced (repositioned basedon the movement of the vessel) to obtain arunning fix.

3.1 Range

A range is created when two charted objects are inline. These objects may be natural (e.g., islands) orman-made (e.g., structures or beacons).

3.1.1 Plotting ranges

A line drawn on a chart connecting two objects (naturalor man-made) defines a range. The label consists of theobserved time the range was crossed (i.e., when the twoobjects are seen to be in line from the boat). The timelabel is placed on the north side of the LOP. The directionis not required because the two objects define the rangeand no direction is measured. The line is dashed where itcrosses land or non-navigable water. A short line near thearea of a fix may be plotted if there is no confusion as towhat two objects are used for the range.

3.2 Bearings and lines of position (LOPs)

Bearings are taken on various charted objects to pro-vide LOP information. Charted objects (some examplesshown here) include aids to navigation, such as buoysand identifiable landmarks, or electronic waypoints(WP) plotted on the chart using coordinates. The sym-bol for a waypoint is a triangle labelled with the way-point name. Bearings are used to establish a boat’sposition and/or to ensure a safe passage (dangerbearings).


3.2.1 Plotting bearings

Bearings are measured by sighting on a clearly visiblecharted object. The LOP direction is determined by thetrue bearing from the boat to the object. It is labelledwith the time of the observation on the north side ofthe line and the true/magnetic direction on the southside of the line. A short line near the area of a fix maybe plotted if there is no confusion as to what sightedobject was used. If the LOP is extended over land, it isdrawn with a dashed line.

3.2.2 Electronic bearings

Electronic bearings are obtained using equipment such asradar, GPS or LORAN. The LOP defines the true directionfrom the boat to a charted object or predetermined way-point on the chart, and is labelled with the time of theobservation on the north side of the line and thetrue/magnetic direction and type of equipment used onthe south side of the line (‘RAD’ = radar, ‘GPS’ = satellite,‘LOR’ = LORAN). A short line near the area of the fix maybe plotted if there is no confusion as to what waypointwas used.


3.2.3 Advanced LOP

An advanced LOP is created by plotting a new locationfor a previously established LOP, based on the calculat-ed movement of the boat since the time of the obser-vation on which the original LOP was based. The LOP islabelled with the time of the original observation andthe time to which the LOP is being advanced on thenorth side of the line, and the true/magnetic directionon the south side of the line.

3.3 Circle of position (COP)

A circle of position is created by measuring the dis-tance from a charted object using a vertical angle, ahorizontal angle, or electronic equipment.

3.3.1 COP using a vertical angle

The COP is an arc using the calculated distance fromplotted object as the radius and the object as the cen-tre. The radius is plotted as a dashed line drawn fromthe object to the arc. The arc is labelled with the timeof the observation on the north side of the line and thedistance away, in nautical miles, on the south side ofthe line.

3.3.2 COP using a horizontal angle

The COP is an arc plotted on the chart based on theangle subtended by two charted objects. Dashed linesare drawn from two observed objects to a point on thearc. These lines should only be extended to the sightedobjects if required to eliminate confusion. The COP islabelled with the time of the observation on the northside of the arc and the size of the horizontal angle, indegrees, is noted inside the lines of the angle.


3.3.3 COP using electronic equipment

The COP is an arc drawn using an identified object asthe centre and a radius equal to the distance awayobtained from radar, GPS or LORAN. The radius is drawnas a dashed line from the aid to navigation or way-point (a predetermined geographical location notedon the chart as a triangle) to the arc. The observationtime is shown on the north side of the arc, and thedistance and electronic equipment used to obtain themeasurement on the south side of the arc(‘RAD’ = radar, ‘GPS’ = satellite, ‘LOR’ = LORAN).

3.3.4 Advanced COP

An advanced COP is created by calculating a new loca-tion for the centre point of a COP arc, based on thetime elapsed and calculated movement of the boatsince the time of the observation on which the originalCOP was based. The COP is labelled with the time of theoriginal observation and the time to which the COP isbeing advanced on the north side of the arc, and thedistance off on the south side of the arc.


4.0 Boat positionsBoat positions can be established using dead reckon-ing or, more accurately, by establishing fixes.

4.1 Dead reckoning (DR) position

A dead reckoning (DR) position is based on the calcu-lated distance travelled along the course line from thelast fix. Dead reckoning positions are established atgiven time intervals, when bearings are taken, orwhen the speed or course of the boat changes. Theyare marked along the course line by a dot, enclosedwith a semi-circle, and labelled with the time. The timeshould be written at an angle to the course line.

4.2 Fixes

A fix is a known position of a boat, which may beestablished in a number of ways. Examples are: beingclose aboard a known aid or predetermined waypoint,intersections of lines of position, use of electronicinstruments, or celestial sights. Fixes are noted on achart by a dot surrounded by a circle and the time.An electronic fix established when underway is identi-fied with a circle, time and the equipment used (‘GPS’= satellite and ‘LOR’ = LORAN). The word ‘FIX’ is notneeded because the circle is the symbol for a fix.

4.2.1 Close aboard fix

A fix is established any time a boat is close aboard acharted aid to navigation or waypoint. The fix islabelled with a circle centred on the aid position, andthe time written plainly off to the side. A predeter-mined waypoint used as a fix is labelled with the timeand a circle surrounding the triangle symbol. The way-point identification must be plainly labelled.


4.2.2 Two-bearing fix

This fix is established at the intersection of two LOPs, ora LOP and a range, or two ranges. The fix symbol (cir-cle) is centred at the intersection, and is labelled withthe time of the bearings. The time should be placed soit can be seen easily and does not interfere with thesurrounding detail. The LOPs must be labelled with thetrue/magnetic direction (on the south side of the line),but the time can be omitted when the LOPs are associat-ed with a fix.

4.2.3 LOP and COP fix

A fix established with a LOP and COP is very similar to atwo-bearing fix. The difference is one of the LOPs is aCOP. The intersection of the LOP and COP is marked withthe fix symbol (circle) and is labelled with the time.The bearing must be labelled with the true/magneticdirection on the south side of the line. The COP mustbe labelled with the distance away from the object onthe south side of the arc and the radius as a dashedline unless the radius is the LOP. The time can be omit-ted on both the LOP and COP when associated with a fix.

4.2.4 Two COP fix

The intersection of two COPs is another method ofobtaining a fix. The intersection of the COPs is labelledwith a circle and the time. The arcs of the COPs arelabelled on the south side of the arc with their respec-tive distances away from the object, and the radii aredrawn as dashed lines from the observed object tothe arcs. The time can be omitted when the COPs areassociated with fix.


4.2.5 Three-bearing fix

A three-bearing fix is established by using three LOPs.These lines seldom meet at a single point and usuallyform a small triangle or ‘cocked hat’. The fix is locatedin the centre of the cocked hat, or at the intersectionclosest to any nearby hazard. The fix is labelled with acircle and time. The true/magnetic directions of theLOPs are placed on the south side of the appropriatelines, but the time can be omitted when the LOPs areassociated with a fix.

4.2.6 Horizontal angle fix

Two horizontal angles with a common side will establisha fix. The fix is labelled with a circle and the time. Thesize of the angles is shown near their intersections. Thesides of the angles should only be extended to the sight-ed objects if required to eliminate confusion.

4.2.7 Electronic fixes

GPS and LORAN equipment can provide latitude andlongitude information directly while underway. Thisposition is plotted on the chart and labelled with acircle, the time, and the equipment used to determinethe fix. (‘GPS’ = satellite and ‘LOR’ = LORAN).


4.3 Running fixes

Running fixes are established using a calculated dis-tance based on boat speed and elapsed time.

4.3.1 Single object running fix

A COP is drawn from the single object using the distancecalculated from a timed run as the radius of COP. Thebearing taken at the end of the timed run is also plotted.The intersection of the LOP and COP is labelled with a cir-cle, the time and ‘RFIX’. The COP is labelled with the dis-tance on the south side of the arc and the LOP with thetrue/magnetic direction on the south side of the line. Thetime can be omitted as they are associated with the fix.

4.3.2 Advanced LOP running fix

A running fix is also established when an advanced LOP

is combined with another LOP. The LOP based on thesecond observation is labelled with the true/magneticdirection on the south side of the line, but the timecan be omitted as it is associated with the fix. Theadvanced LOP is labelled with the time of the originalobservation and the time to which the LOP is beingadvanced on the north side of the line, and thetrue/magnetic direction on the south side of the line.The fix itself is labelled with a circle, the time, and‘RFIX’.

4.3.3 Advanced COP running fix

This fix is the same as the advanced LOP running fixexcept that a COP is advanced. Labelling consists of acircle at the intersection forming the fix, along withthe time and ‘RFIX’. The LOP is labelled with thetrue/magnetic direction on the south side of the line,but the time can be omitted as it is associated with thefix. The advanced COP must be labelled with the timeof the original observation on which it was based andthe time to which the COP is being advanced on thenorth side of the arc, and the distance on the south


side of the arc.4.4 Estimated position (EP)

Estimated positions are DR positions corrected forexternal influences affecting the progress of the boat.

4.4.1 EP without current

The EP is located on the LOP by drawing a constructionline (dashed) from the DR position at the time thebearing was taken, perpendicular to the LOP. A squareat the intersection of the LOP and construction lineidentifies the EP. No time is needed at the EP location.

4.4.2 EP with current

A scaled current vector, calculated using known valuesof set and drift, is drawn from a DR position. It islabelled with the set (‘SET’ and true/magnetic direc-tion) and drift (‘DFT’ in knots) and headed with a sin-gle arrowhead. The EP is located at the end of the cur-rent vector. To establish an EP on an associated LOP

draw a construction line (dashed) from the end of thecurrent line perpendicular to the LOP. A square at theend of the current arrow or the intersection of the LOP

and construction line identifies the EP. No time isneeded at the EP location.


5.0 Standing clear of dangerDanger angles and danger bearings are used to ensurea boat stays in safe water.

5.1 Danger angles

Danger angles are predetermined vertical or horizontalangles establishing the limits of a dangerous area.

5.1.1 Vertical danger angles

Arcs, with radii determined by measuring verticalangles, are drawn to identify hazardous water areas.Arcs labelled with ‘NMT’ (not more than) and the sex-tant angle identify hazards inshore from the arc. Arcslabelled with ‘NLT’ (not less than) and the sextantangle identify hazards seaward from the arc. Thelabelling is placed on the ‘safe’ side of the arc.

5.1.2 Horizontal danger angles

Arcs, determined by a horizontal angle measuredbetween two charted objects, are drawn to identifyhazardous water areas. The angles are labelled with‘NMT’ (not more than) and the angle to identify haz-ards inshore from the arc. The angles are labelled with‘NLT’ (not less than) and the angle to identify hazardsseaward from the arc. The labelling is placed insidethe angle.


5.2 Danger bearings

A danger bearing establishes the limits of a dangerousarea. Bearings are drawn to a charted object so that itclears the danger area and ‘feathered’ on the danger-ous side. If the hazard is on the port side, the bearingis labelled with true/magnetic direction, preceded withthe letters ‘NMT’ (not more than). If the hazard is onthe starboard, the bearing is labelled with true/mag-netic direction, preceded with the letters ‘NLT’ (notless than).


6.0 Vectors usedin current problems

Vectors are used to solve current problems and whenlocating estimated positions established with current.Vectors represent motion by graphically showing direc-tion and speed (vector length equals speed multipliedby time).

6.1 Course to steer

The length of the plotted ‘course to steer’ vector isequal to the scaled distance of travel through thewater, and is plotted with a single arrowhead pointedin the direction of travel. The line is labelled with thecourse (‘C’ and true/magnetic direction) on the northside of the line and the boat speed (‘S’) on the southside of the line.

6.2 Track or Track made good

The length of the plotted track or track made good(TMG) vector is equal to the scaled distance of traveland is plotted with a single arrowhead pointed in thedirection of travel. If the line represents the Track, it islabelled with ‘TR’ and true/magnetic on the north sideof the line, and speed of advance (‘SOA’) on the southside of the line. If the line represents the track madegood, the line is labelled with ‘TMG’ true/magneticdirection on the north side of the line, and the speedmade good (‘SMG’) on the south side of the line.

6.3 Current

The length of the plotted current vector is equal to thescaled distance of the current travel and is plotted witha single arrowhead pointed in the direction of currentflow. The line is labelled with ‘SET’ and true/magneticdirection on the north side of the line and ‘DFT’ andspeed on the south side of the line.


6.4 Current vector diagrams

The example at the right is an illustration of completedcurrent vector diagram. Current vector problems arenormally done on work sheets to eliminate clutter onthe chart.

6.5 Current from a DR plot

The current vector is drawn from a DR and the correspon-ding fix. The line, headed by a single arrowhead, islabelled with the ‘SET’ and true/magnetic direction onthe north side of the line and the ‘DFT’ and speed on thesouth side of the line or may be offset, as shown, whenspace is limited.


7.0 Celestial navigationCelestial navigation uses a plotting system similar tocoastal piloting. The main difference is the plot isbased on celestial observations.

7.1 Celestial lines of position

Celestial LOPs are similar to terrestrial LOPs, except theyare based on celestial sights.

7.1.1 Azimuth line

The azimuth line is plotted from a DR position (or anassumed position) in a specified true direction and dis-tance based on data from the sight reduction calcula-tion. It is plotted as a dashed line. The LOP is drawn asa perpendicular line at the end of the azimuth line.

7.1.2 Celestial Line of position

A celestial line of position is plotted on a chart usingdata from the sight reduction calculation. It is labelledwith the time on the north side of the line and thebody used for the sight on the south side of the line.The time can be omitted when the LOP is associatedwith a fix


7.2 Celestial fixes

Celestial fixes are plotted from data obtained fromsextant sights.

7.2.1 Simultaneous sights

A fix from simultaneous sights is determined by theintersection of two or more celestial LOPs from sightstaken within a few minutes of each other. The fix islabelled with a circle and the time of the last sight. TheLOPs are labelled with the observed body on the southside of the line. The time of LOPs may be omitted asthey are associated with the fix.

7.2.2 Running fix

A running fix is established when an advanced celestialLOP is combined with a later LOP. The fix itself islabelled with a circle and ‘RFIX’. The later LOP islabelled with the observed body on the south side ofthe line, but the time may be omitted, if desired. Theadvanced LOP must be labelled with the time of theoriginal observation and the time of the fix on thenorth side of the line, and the observed body on thesouth side of the line.


7.3 Estimated position (EP)

An estimated positions (EPs) is a DR positions correctedfor external influences affecting the progress of aboat.

7.3.1 EP without current

A dashed line is drawn at right angles to the LOP for asight, from the DR position. The intersection at the LOP

is labelled with a small square.

7.3.2 EP with current

A current line is drawn from the DR position for thetime of a sight and is labelled with the Set (‘SET’true/magnetic direction) and Drift (‘DFT’ in knots) andheaded with a single arrowhead. The EP is located onthe LOP by drawing a construction line (dashed) fromthe end of the current vector perpendicular to the LOP.A square at the intersection of the LOP and construc-tion line identifies the EP. No time is needed at the EP

location.


7.4 Miscellaneous plotting

There are two unique notations used in celestial naviga-tion, namely; time zone crossing and variation changes.

7.4.1 Time zone crossing

A dashed line is drawn across the course line andlabelled on either side with the appropriate time zoneprefixed with ‘ZD’. The first DR position after crossingthe time zone line is labelled with the time from bothtime zones.

7.4.2 Variation change

A dashed line is drawn across the course line andlabelled with the word ‘VAR’ on either side with theappropriate amount of variation.

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7.0'

W12

920

E10

90

109

6.0

1.9

0919

Lv. L

adys

mit

h H

arbo

ur, f

rom

LS

MIT

H

0919

DR

48°

57.9

'N12

3° 4

4.8'

WBo

ulde

r Pt

. abe

am t

o st

bd (n

o LO

P pl

ot)

0919

Crs

chg

009

20E

349

034

96.

07.

510

34Ch

ange

Crs

for

Rux

ton

Pass

age

0948

DR

49°

00.7

'N12

3° 4

4.2'

WTo

ok 2

com

pass

brg

s

0948

C Br

g33

920

E31

90

319

Yello

w Pt

. Lt.

(319

° C)

0948

C Br

g08

620

E06

60

066

Fras

er P

t. L

t. (0

66°

C)

0948

FIX

49°

01.1

'N12

3° 4

4.2'

W00

920

E34

90

349

6.0

3.9

1027

2 Br

g fi

x, c

onti

nue

009°

cou

rse

1000

DR

49°

02.3

'N12

3° 4

4.0'

WYe

llow

Pt. G

buo

y ab

eam

to

port

(no

plot

)

1011

DR

49°

03.3

'N12

3° 4

3.7'

WD

ange

r Re

efs

abea

m t

o st

bd (n

o pl

ot)

1027

DR

49°

04.9

'N12

3° 4

3.3'

WTo

ok 2

com

pass

brg

s

1027

C Br

g33

620

E31

60

316

Red

buoy

QR,

Wes

t Ru

xton

Pas

s (3

16º

)

1027

C Br

g05

020

E03

00

030

SE

tip

of D

e Co

urcy

(03

0°C)

1027

FIX

49°

05.1

'N12

3° 4

4.1'

W2

Brg

fix.

Set

292

°, dr

ift

0.8

kn

1027

Crs

chg

Conn

ing

6.0

0.9

1036

Con

east

thr

ough

Rux

ton

Pass

to g

reen

buo

y Fl

G.

1036

FIX

49°

05.3

'N12

3° 4

2.9'

WCl

ose

aboa

rd g

reen

buo

y Fl

G

1036

Crs

chg

355

20E

335

033

56.

02.

310

59Co

urse

to

Dib

uxan

te P

t.

1059

DR

49°

07.6

'N12

3° 4

3.2'

WD

ibux

ante

Pt.

Lt. a

beam

to

stbd

(no

LOP

plot

)

1059

Crs

chg

Conn

ing

6.0

2.4

1123

Con

east

thr

ough

Gab

riol

a Pa

ss

1100

DR

Use

105

9 D

R as

110

0 D

R



Dec

k Lo

g F

orm

DEC

K L

OG

– V

ESSE

L:D

ebut

ant

NA

VIG

ATO

R:

Ima

Boat

erD

ate/

Ob

ser-

Lati

tud

eLo

ng

itu

de

TV

MD

CSp

eed

Dis

t.ET

AR

emar

ks

tim

eva

tio

n(U

se t

wo

lin

es if

nec

essa

ry)

July

4,2

003

1123

FIX

49

° 07

.0'N

123°

40.

0'W

Clos

e ab

oard

Δ G

AB

E

1123

Crs

chg

145

20E

125

012

58.

06.

112

09Co

urse

to

Porl

ier

Pass

ran

ge

1200

DR

49°

03.5

'N12

3° 3

6.1'

WH

ourl

y D

R

1209

DR

49°

02.0

'N12

3° 3

4.6'

WIn

ters

ect

Porl

ier

Pass

ran

ge

1209

Conn

ing

5.0

2.3

1237

Con

thro

ugh

Porl

ier

Pass

to

Δ W

PO

R

1235

FIX

49°

00.0

'N12

3° 3

6.0'

WCl

ose

aboa

rd Δ

W P

OR

1235

Crs

chg

216

20E

196

019

66.

00.

612

41Co

urse

to

pass

sou

th o

f Re

id I

.

1241

DR

48°

59.6

'N12

3° 3

6.5'

W

1241

Crs

chg

191

20E

171

017

16.

01.

913

00Co

urse

to

pass

sou

th o

f N

orwa

y I.

1258

DR

48°

57.9

'N12

3° 3

7.0'

WBr

g an

d co

urse

cha

nge

1258

C Br

g15

020

E13

10

131

Sout

h Pt

. Lt.

(131

° C)

1258

Crs

chg

180

20E

160

016

06.

02.

713

08Co

urse

to

clea

r Sa

ndst

one

Rks

1300

Hou

rly

DR

not

plot

ted,

use

125

8 D

R

1309

DR

48°

56.9

'N12

3° 3

7.0'

WTo

ok c

ompa

ss b

rg

1309

HC

Brg

085

20E

065

006

5So

uthe

y Pt

. Lt.

(065

° C)

Han

d co

mpa

ss B

rg

1309

RFIX

48°

56.7

'N12

3° 3

6.7'

W18

020

E16

00

160

6.0

2.3

1332

Adv

ance

125

8 LO

P fo

r RF

IX

1332

DR

48°

54.3

'N12

3° 3

6.7'

WD

R fo

r GP

S FI

X

1332

GPS

FIX

48°

54.2

'N12

3° 3

7.3'

WGP

S po

siti

on

1332

DR

(Cur

)48

° 54

.5'N

123°

37.

0'W

Curr

ent

set

215°

, dri

ft 0

.4 k

n


Dec

k Lo

g F

orm

DEC

K L

OG

– V

ESSE

L:D

ebut

ant

NA

VIG

ATO

R:

Ima

Boat

erD

ate/

Ob

ser-

Lati

tud

eLo

ng

itu

de

TV

MD

CSp

eed

Dis

t.ET

AR

emar

ks

tim

eva

tio

n(U

se t

wo

lin

es if

nec

essa

ry)

July

4,2

003

1332

Crs

chg

296

20E

276

027

66.

03.

714

09Co

urse

to

Bare

Pt.

, Ch

emai

nus

1400

DR

48°

55.5

'N12

3° 4

1.2'

W

1407

FIX

48°

55.8

'N12

3° 4

2.4'

WCl

ose

aboa

rd B

are

Pt. L

t.

1407

Crs

chg

Conn

ing

Con

into

har

bour

to

whar

f

1420

Tie

up14

20Ti

e up

at

Chem

ainu

s Go

vt. w

harf

No

tes:

Du

e to

ch

art

con

ges

tio

n s

om

e lin

es a

re n

ot

plo

tted

, or

if p

lott

ed t

hey

wer

e n

ot

lab

elle

d. S

ee n

ote

s in

log

.D

Rs

sho

wn

as

bei

ng

'ab

eam

' are

est

ablis

hed

by

visu

al s

igh

tin

gs

(th

at is

, co

mp

ass

bea

rin

gs

wer

e n

ot

take

n a

nd

no

LO

P p

lott

ed).

Th

e D

R is

plo

tted

on

th

e co

urs

e lin

e d

irec

tly

op

po

site

th

e si

gh

ted

fea

ture

.

Course Plottingand Labelling Standards Plotting and Labeling... · Course Plottingand Labelling Standards Canadian Power & Sail Squadrons| 1st edition 2005 Revised 2007, 2008

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