Past couple of weeks I have been getting out with my marina neighbor Dustin. Dustin's a great guy, computer wiz, that works mostly from his boat so he's COVID safe.
Dustin's been an awesome crew member, and additionally has a nice eye for photography. Here's a couple of his shots over the couple weeks.
Two important exams for passing the USCG 100 Ton Master’s Exam are Navigation and The Rules of the Road. Both of which you must have a 90% grade on to pass. I did two things which helped me get a 98% on the exam first pass.
The first was watching the YouTube video from (www.youtube.com/watch?v=J4gLCwLWLK0) everyday twice a day for two weeks. Secondly I wrote the following poem and memorized it. I hope these help you pass the exam as well.
Sailing Poem
One night while on watch I spotted there,
My ship’s captain with graying hair,
As I walked aft, he spotted me,
I said, “what does it take to be a captain, like thee”,
He puff his pipe, his face turned a frown,
“You’ll memorize this lad, so jot it down,
The rules of the road is what you’ll need
So pay attention lad, and take heed,”
“When you see another sailing ship at night, you’ll know
If the lights are green it’s off we go,1
If it’s red, heave too, it’s his port ahead1
A white light of 135 degrees, it’s her stern,” he said.
“The stink pots are all just like this2,
Blood over water, that boat’s catching fish,
Green over white they’re trawling a-head,
But red over red means her captain is dead.3”
“Lights white over white shows a short tow in sight;
Yellow over white thus his hawser is tight.4”
“Three whites in a row, it’s a hell of a tow, 5
A yellow over yellow, that pushy inland Capt’n Joe 6”.
“Oversea three reds means draft is way low,7
White over the red, you’ll know, it’s pilot below
Three green’s on a tree, there’s a mine sweep near me,8
Two reds bounding white, RAMs ar’ they be.9”
“A white, two reds going down, she’s aground, still at sea, 10
Two whites apart, a lower red sided by green, the bow of 50m it be 11
One white high, a lower red sided by green, a small streamer head on
Over 100m, two whites apart, a lower red and green, her deck lights too are all go on”
“During the day the messages all contain,
With some balls, diamonds, a can, and cones are in this refrain,
Two balls on a dredge, stay clear, go around,13
But two diamonds you pass by and you’ll be sound.13”
“Two cones, apexes that touch, he’s fishing or trawling as such
An apex pointed to the ground, motor is on and sails go down14,
When the apex is up, 100m of fishing gear near,
A can in her mast means the draft disappeared.”
“One ball hanging high, at anchor in her bed 15
Two balls in a row, the captain is dead below,
Three balls, stay clear, aground is she,
Two balls bounding a diamond, it’s a RAM let her be.”
“One diamond in the air, means simply there’s a tow back there,
Another diamond at the end you’ll see 200m submerged beware
Tow boats towing can be RAMs or NUCs
If three balls in a row they’re still stuck. 16”
“Over night rooms for sale plus supper, is nothing Jack,
Or’taking, NUC, RAM, Fishing, Sailing, Power, Seaplane is that stack.
A special case they tell me, is up on the Mississippi
Tugs they have no masthead as they go, the bridges are too low.”
“Memorize these words, you’ll be a captain that knows the rules,
But caution and beware as if you’re stand on and the others are fools,16
Stand watch all night and you’ll be fine,
At your own captain’s table you’ll dine.”
Footnotes:
1. Rule 12 for which side the red and green sidelights go on
2. Stink pot is a vessel under power.
3. Captain’s not literally dead, the vessel is Not Under Command NUC something is broken on the vessel.
4. Hawser is a tow line being towed from behind the tow boat.
5. Rule 24d a 200m tow in length
6. Rule 24f Inland pushing ahead.
7. Rule28 International only vessel contained by draft
8. On a tree meaning the cross of the mast with a light on each branch top, port, and starboard.
9. Restricted in Ability to Maneuver RAM
10. Rule 30 a vessel aground at night or limited visibility
11. Rule 23 a
12. Rule 27d Dredge
13. Rule 27d Dredge
14 Rule 25c
15. Rule 30
16 Stuck - being aground….
Abstract
After taking the Navigational Charting Exam as part of the USCG 100 Ton Master Requirement a set of notes was compiled which may help aid future mariners in passing the exam. Several tips and tricks are listed which I discovered after some frustration upon failing practice exams.
1.0 Introduction
While taking the Navigation Charting Exam as part of the USCG 100 Ton Master exam I became frustrated after not passing several of the practice tests. The exam is made up of 10 questions, with most of the questions having a dependency which builds upon each other. As a result if a candidate gets an answer wrong in the first few questions, it’s likely the candidate will have incorrect answers on the exam going forward. More importantly the requirement for passing the exam is to have 90% of the answer correct; or no more than one incorrect answer.
In preparation for the exam the USCG issues practice tests. To illustrate the importance of errors, accuracy, precision and mistakes let’s look at one of the practice exam questions.
QUESTION: You are on course 056°psc, when you take the following bearings:
New Point Comfort Spit Light "2" 260°psc
Horn Harbor Entrance Light "HH" 285°psc
Wolf Trap Light 336°psc
What is the position of the fix?
Examination of the answers shows there is only a variation of 1’ in the choices latitude and 6’ in the variation of longitude. The examination are usual done on charts with a scale of 1:80,000, and one minute of latitude is a represents one nautical mile. With this in mind let’s examine a simple 0.7mm lead mechanical pencil’s effects on judging out latitude from the sample question. Considering 1 inch is equal to 25.4 millimeters and we are using three bearings which cause an overlap of three drawn lines to find our fix as asked in the sample question, it’s possible our 3 lines overlap in such a manner that the lines stack at the intersection as shown in the diagram below.
Based on this diagram, roughly the overall stack of the three lines amounts to a thickness nearing (3*0.7mm=2.1mm) 2.1mm. From this issue alone there is an error induced of nearly 1/10th of nautical mile. The error is much worse if the lines don’t intersect exactly.
Let’s also consider the errors introduced by starting the line just off the aid to navigation (ATON). On a coastal chart of 1:80,000 line widths on the chart range from 0.1mm thick to nearly 1mm in thickness. Using a caliber measurements of ATON features were done on chart 12221TR, the training chart used for some of the charting exams. The following measurements were found:
Lighted Markers had terminations between 0.1mm-0.25mm diameter
Day Buoys had termination between 0.3-0.6mm diameter
Cape Henry Lighthouse 0.4mm diameter
Considering now the errors in alignment to these ATONs introduces a greater variance in selecting the correct answer to exam questions
Incorrect alignment to a non-lighted buoy
From the image above if the pencil used is a 0.7mm mechanical pencil, the error again is at worst 0.3mm (1/2 the largest diameter) + 0.7mm (width of the lead) = 1.0mm or 1/20th of a nautical mile.
Consider the instance in which the candidate made the same errors on each of the three lights listed in the question, and added to it the three line stack, the summed errors amount to between 0.2 to 0.4 nautical miles in error. Thus far our analysis hasn’t consider variations in the lead of pencil not in contact with the straight edge to draw the line, the variation in the straight edge to be truly straight, and a host of other errors. In accounting for all the slight possible errors one could make in the mechanical tolerance associated with drafting lines for triangulation to achieve a fix I found the error could easily be between 2.67’ and 3’ of error.
If I could eliminate all the errors in the mechanical tolerances I found I could achieve an error less than 0.04’. To achieve this greater accuracy and precision I first needed to get into the minds of the examiners, and took from The American Practical Navigator (aka Bowditch).
2.0 Definitions from Bowditch
To understand the context of errors, accuracy, precision and mistakes, one should consider the definitions in context of how the USCG may define the terms. From Pub. No. 9 The American Practical Navigator, 2002 Edition (aka Bowditch) the definitions are:
“A standard is a value or quantity established by custom, agreement, or authority as a basis for comparison. Frequently, a standard is chosen as a model which approximates a mean or average condition.”
“A mistake is a blunder, such as an incorrect reading of an instrument, the taking of a wrong value from a table, a data entry error, or plotting a reciprocal bearing.”
“Accuracy is the degree of conformance with the correct value, while precision is a measure of refinement of a value.”
“Error is the difference between a specific value and the correct or standard value. As used here, it does not include mistakes, but is related to lack of perfection.”
In a later chapter in Bowditch the authors show a Pareto ranking of failures in navigation which resulted in ships going aground. This Pareto ranking is shown below:
The authors of Bowditch follow with,
“Some of the errors listed above are mechanical and some are matters of judgment. Conscientiously applying the principles and procedures of this chapter will go a long way towards eliminating many of the mechanical errors. However, the navigator must guard against the feeling that in following a checklist he has eliminated all sources of error. A navigator’s judgment is just as important as his checklists. Systematic errors are treated differently. Generally, the navigator tries to discover the errors and eliminate them or compensate for them. In the case of a position determined by three or more lines of position resulting from readings with constant error, the error might be eliminated by finding and applying that correction which will bring all lines through a common point.
Lines of position which are known to be of uncertain accuracy might better be considered as “bands of position”, with a width of twice the possible amount of error. Intersecting bands of position define areas of position. It is most probable that the vessel is near the center of the area, but the navigator must realize that he could be anywhere within the area, and must navigate accordingly.
The recognition of a mistake, as contrasted with an error, is not always easy, since a mistake is random, may have any magnitude, and may be either positive or negative. A large mistake should be readily apparent if the navigator is alert and has an understanding of the size of error to be reasonably expected. A small mistake is usually not detected unless the work is checked.
If results by two methods are compared, such as a dead reckoning position and a line of position, exact agreement is unlikely. But, if the discrepancy is unreasonably large, a mistake is a logical conclusion. If the 99.9 percent areas of the two results just touch, it is possible that no mistake has been made. However, the probability of either one having so great an error is remote if the errors are normal. The probability of both having 99.9 percent error of opposite sign at the same instant is extremely small. Perhaps a reasonable standard is that unless the most accurate result lies within the 95 percent area of the least accurate result, the possibility of a mistake should be investigated. “
3.0 Best Known Methods for Charting on the Exam
Using the above information from Bowditch, and my many years teach mechanical drafting in college I developed best known methods for charting. Using these methods I achieve a perfect score on every practice exam and on the actual USCG exam. First consider I will consider the tools needed, and then best practices.
3.1 Charting Tools
As a disclaimer I don’t have any financial interest in Weems and Plath, nor am I a big fan of theirs, although it may seems like as you read the next section. The tools were recommended after I did extensive testing from many vendors. Whenever a Weems and Plath tool would break I returned it to the retailer and they replaced immediately with no questions asked. I broken at least three Weems and Plath charting tools and everyone was replaced without a single question.
3.2 Do Some Simple Practicing
Using just simple plain white copy paper practice drawing lines, draw lines parallel to each other, draw circles using the compass and the stencil, practice erasing parts of these drawings. Use every straight and every tool at least 20 times.
Although it’s going to seem basic let’s talk about how to draw a straight line. Drawing a straight line should be practiced several times, at various lengths and various widths.
Precise drawing style is important and critical in achieving a minimal error. The best practice is to keep the pencil lead touching the to straight edge with the pencil as close to perpendicular to the chart as possible. As the line is being drawn pull the pencil along the straight edge, keeping the two in contact, slightly rolling the pencil back and forth as the line is being drawn. See style B in the drawing below.
The rolling of the pencil as it is being pulled creates a line with an even thickness, and constant width as the graphite of the pencil is being laid down on the chart.
When the wood of the pencil is in contact with the straight edge the pencil will lean and tend to drift away from the straight edge and intended line as seen in Style A above. Over the course of 6 to 8 inches using style A above could create an error of 1o to 3o off the intended course.
Another best practice can be used when one or both of your termination points is at an ATON. The secret is to take the point of you compass to make a hole in the exact center of the ATON, push it down to create a small hole. Place the point of the pencil into the newly created hole and use it to align your straight edge to the desired bearing. Don’t move the pencil from the hole because once the straight edge is in place begin drawing the line from the hole. If you practice this technique you’ll soon see your alignment is perfect to the ATON, meaning you’ve reduced the errors discussed earlier.
3.3 Best Known Methods for Plotting on charts.
For example if you're asked to find the bearing between two points. First use your Weems and Plath Professional Protractor Triangle and your Weems Parallel Roller Plotter to determine the bearing off the closest meridian. For argument sake let's say the bearing was found to be 223o T (T stands for True North). Next on your scratch paper “Bearing = 223o T using W&P Triangle”. Remove the triangle from the chart. Now use your Weems Parallel Roller Plotter to walk the angle to the nearest compass rose. On the compass rose you see the bearing is 222o T. Again write on your scratch paper ““Bearing = 222o T using Roller and Rose”. If the multiple choice answers include one of these two you're done, but if the includes both, try another method. Use the Weems and Plath Paralock to walk the bearing to the compass rose. If then you read the compass rose and it reads 223o T you’ll like have the answer at 223o T. If there is a larger variation between the two or three methods you have have made a mistake somewhere, try taking the measurements once again.
For example if you’re doing a time of arrival calculation and you know the speed (say it’s 5.5 KN) and distance (8.0 NM). (Note KN is Nautical Miles Per hour and NM is Nautical Miles.). You should write out on the scratch paper:
Time = Distance/Speed = 8.0 (NM) / 5.5 (NM/HR) = 1.454 HRS or 01:27 HH:MM
Another example if you are plotting on the chart.
Notice in the figure above the each line is labeled with a course C=310oT, where T stands for True North, and an arrow on the line indicating the direction. Below the line the Speed, “S” is marked with proper units in nautical miles per hour. The arrow reminds you that you’re going from one point to another. If a mistake is made in the mathematics and your true bearing doesn’t fall within the compass quadrant the arrow on the path makes this mistake readily apparent. As an example if once done with the math of the problem, and your heading is resolved to 220oT, one should know that 220oT is SSW and should point downward not NW. Ergo some mistake must have been made. Also notice the marker is highlighted green with the Neon Page Markers Colored Index Tabs, making it easy to find on the chart.
Each fix or DR in the example above is labeled with it’s question number on the exam, i.e. Q3, or Q6, for question 3 or 6 respectively. The fixes were drawn using the stencil suggested, which adds a level of neatness and professionalism to your charting.
First let’s actually look at the photograph of the area below. In this photograph, the three crowded features near the shoreline become apparent. The first is a tower marker TR on the chart. The next structure is the actual Cape Henry Light, which is described in the Coastal Pilot Region 3 below. The next feature is an abandon lighthouse, and the further southward and slight to the west is the tank discussed in the Coastal Pilot below.
Extract from Coastal Pilot Region 3
“The Maryland pilots maintain a Pilot Tower with the Virginia pilots at Cape Henry, just north of Cape Henry Light. The pilots monitor VHF-FM channels 11, 13 and 16. The pilot boats are stationed in Lynnhaven Inlet. They are 52 feet long with a black hull and white house displaying the “PILOT” on each side.
Cape Henry Light (36°55'35"N., 76°00'26"W.), 164 feet above the water, is shown from an octagonal, pyramidal tower, upper and lower half of each face alternately black and white, on the beach near the turn of the cape.
The gray octagonal, pyramidal tower 110 yards southwest of Cape Henry Light is the abandoned 1791 lighthouse.
Local magnetic disturbance
Differences of as much as 6° from the normal variation have been observed 3 to 17 miles offshore from Cape Henry to Currituck Beach Light.
A naval restricted area extends northward and eastward from Cape Henry. (See 33 CFR 334.320, chapter 2, for limits and regulations.)
The summer resort of Virginia Beach is about 5 miles southward of Cape Henry Light. Many high-rise buildings, two water tanks, and an aerobeacon 2.8 miles inland are prominent. A hotel cupola, 3.4 miles south of Cape Henry Light, is distinctive.“
The important take away is that one should read the Coastal Pilot about the landmarks and ATON when they are on the exam. The Coastal Pilot gives you the exact LAT/LONG for the light, and explains which of the four possible features is the Cape Henry Light. So before highlighting and using the ATON for bearings or triangulations to a fix be certain you are on the correct ATON. See below
3.4 Being Methodical In Charting and in the Exam
During the charting exam you will be provided with two white sheets of paper for scratch paper, the exam book with the questions, an answer sheet, the chart needed for the exam, the light list, and the Coast Pilot for the region your chart is in, and your navigation tools. My recommendation is to treat every practice exam like it was the real exam, only use what is intended during the exam.
1. Do this before anything else:
At the top of one of the pages of the scrap paper write out the following:
Although writing these down at first may seem like a waste of time, it actually sets you mind into a framework of doing the exam and eases stress about taking the exam. Remember the USCG doesn’t grade of how fast you answer only that you answer correctly.
2. Set the answer sheet to the side don’t even mark on it until you’ve finished the exam.
3. Open the exam book and read the first question and all the answers twice. Below is an example from the sample test.
VARIATION IS 9° W
DEVIATION TABLE
HDG.MAG. DEVIATION
---------------------------------------
000° 2.0°E
030° 3.0°E
060° 4.0°E
090° 2.0°E
120° 1.0°E
150° 1.0°W
180° 2.0°W
210° 3.5°W
240 3.0°W
270° 1.5°W
300° 0.0°
330° 1.5°E
Q1. At 0939 your GPS position is LAT 36°57.0'N, LONG 75°41.0'W. You are on course 119° per standard magnetic compass at a speed of 12.8 knots. At 1017 your GPS indicates your position as LAT 36°54.2'N, LONG 75°33.1'W. What were the set and drift?
(A) 103°T at 1.1 knots
(B) 091°T at 1.6 knots
(C) 275°T at 1.8 knots
(D) 280°T at 1.0 knot
On the scratch paper actual write out:
Q1 :
GIVEN: @ 0939 GPS LAT 36°57.0'N, LONG 75°41.0’W
C=119°C S=12.8 KN
@1017 GPS LAT 36°54.2'N, LONG 75°33.1’W.
WANTED: SET and Drift
ANALYSIS:
T. 111o. Plot this course from our GPS fix at 0939
V. 9oW
M 120°
D 1oE
C 119°
1017-0939 = 0 hours 38 minutes
D=ST/60 = 12.8KN*38/60 HOURS= 8.106NM
Immediately from plotting the results I get 275oT and 1.8KN, therefore choose C.
4. Once you’ve finished the 10 questions on the scratch paper, bring out the bubble exam answer sheet. Fill in each bubble correctly with the corset answers, then go from 1 to 10 and check you answers once more.
3.5 Take at least two practice exams every day leaving up to the actual exam.
During the exam you may be asked use a given bearing from New Pt Comfort Light “2” which is in the green box. But notice if you are not careful you may easily select the ATON in the red box, as it has a sounding of 2 next to it. Or you may be not careful and select “2P” in the yellow.
Similarly in the same region if ask to use the ATON “4” from New Point Comfort you could easily mistake the two ATON’s in the blue and purple box. One should double check that your assumptions before plotting bearings and positions to know the ATON’s are correct. Familiarizing yourself with the chart and double checking the ATON’s is the best way to avoid such errors.
4.0 Conclusions
The best advice I got before the exams came from reading the side of the drink bottle, “As is in life, chill for best results.” If you practice a couple times a day, go slow, double check your answers, draw straight lines, use the tips included in this paper, your likelihood to pass is better than not.
5.0 References
