Prologue
In 1995, Captain Francisco J. Labarta, wrote the first edition of Elements of Navigation in an effort to summarize and communicate to future mariners a small part of his vast knowledge of navigation. In this current revision, the content has been updated and expanded to reflect the technological changes and practical considerations for the modern recreational motor boater. While the advent of the chartplotter and an array of other technologies have greatly advanced and simplified navigation, an understanding of the elements of navigation underlying the technology makes for a more competent vessel operator. The revised text attempts to retain as much of the original publication's narrative and topics as possible without introducing details that are, in today's world, beyond the scope of the recreational boater.
Introduction
I am not sure Captain Labarta necessarily loved the sea. He didn't swim, didn't like the sand, avoided the sun, but he loved what the sea represented. The sea does not pick favorites, nor does she necessarily reward the most able; however, the sea does not suffer fools lightly and will strike at those who are ill-prepared or unsuited for the conditions and circumstances she may present. When at sea, like God himself, she is the last arbitrator of fate.
This book is dedicated to promoting the security, respect, consideration and good conduct between mariners wherever we sail our vessels. The sea and navigable waterways are the heritage of all and should be protected from irresponsible actors and criminals so that the young sailors of today may be the good mariners of the future.
Captain Francisco J. Labarta
Master, All Oceans
The book will communicate to the competent mariner a general vision regarding navigation and illustrate the necessity for certain basic skills and knowledge in order to enjoy boating in a secure manner for the sake of the operator, passengers, and others that share our navigable waterways.
The operation of a marine vessel is regulated by rules and obligations that require adherence. The operator has a great responsibility to him or herself, guests and other boaters. On the water, there are no traffic signs or traffic police; however, it is everyone's responsibility to comply with current regulations and have consideration for others.
In order to operate a vessel in a responsible manner, from the beginning, the mariner should learn basic navigation skills and understand how to operate the vessel with minimal risk. The basic knowledge points include:
Understand the vessel's construction, capacities, and limitations, and the boat's basic maintenance requirements.
Learn and practice basic boat handling including docking, anchoring, boarding and cruising.
Understand the use of lines (ropes) appropriately, including proficiency with common knots.
Understand federal and state laws as they pertain to the operation of the vessel in the applicable waterways.
Understand and interpret the aids to navigation commonly used.
Understand rules of navigation that regulate traffic and the rules governing right of way when vessels are in visual proximity.
Understand the general operation of sailing vessels so that one can understand the limitation of their navigation.
Understand basic weather, wind, tide and other meteorological information.
Understand basic VHF radio communication including radio checks, DSC, and manner of usage that prevents interference with others.
Understand basic methods of rendering assistance to other vessels and calling for coast guard assistance when needed.
Understand navigation basics including the use of modern electronics and also, the use of coastal navigation and dead reckoning techniques.
This book does not seek to train the student as a professional navigator. There are many educational courses available to further the student's knowledge in this area. However, this book will provide the basic knowledge to understand navigation concepts along with other topics that may be appropriate for the modern recreational operator.
Welcome to Elements of Navigation.
1 - Introduction to Navigation
Navigation refers to the art of determining the geographic positioning of a vessel on the sea at a moment in time and to move the vessel from one point to another knowing the position of the vessel throughout its course of travel.
There are four categories of marine navigation:
Coastal Piloting - Navigation within the sight of land, using visible landmarks to determine course and distances in order to reach a predetermined location.
Dead Reckoning - Navigation using a known starting point and applying course and estimate of speed over time to determine location.
Celestial Navigation - Navigation using the height of celestial bodies over the horizon measured by a sextant and using pre-calculated trigonometric tables to estimate position.
Electronic Navigation - Navigation using satellite, radar, and other electronic means to complete navigational tasks.
System of Coordinates
We start with an introduction to how one follows direction at sea. For the moment, envision a city map where streets run East and West and avenues run North and South. It is easy to visualize a system of parallel lines forming a grid.
Now we can divide the grid into four quadrants by drawing an E-W and N-S axis (darker lines). As with streets, the intersections of the lines can have numbers applied to denote locations with the starting point represented in this case by the intersection of the dark lines (N-S crosses E-W).
When we think of map or a "chart" as it is referred to in nautical terms, we are really looking at a flat projection of some section of a round globe. One can imagine how uncomfortable it would be to work on a globe when attempting to draw a course. The streets which run E-W on the map are represented on a chart as Parallels and the avenues which run N-S are referred to as Meridians.
The Meridians determine the distance from the Prime Meridian which has an address of zero, or 0 degrees and crosses through the Royal Observatory in Greenwich, UK (dashed line). Lines that are left of the Prime Meridian represent Western locations and lines to the right of the Prime Meridian represent Eastern locations. The Meridians can be viewed as equally sized large circles that cross both the North and South poles as they encircle the globe.
The Parallels are circles that run parallel to the Equator and become smaller as they move away from Equator towards the Poles. The Equator is the Parallel that divides the globe into two equal halves (top and bottom) and has the address of zero or 0 degrees. The Equator is the longest Parallel and is equal in size to the circumference of the Earth (21,614 Nautical Miles). Lines that are above the Equator represent Northern locations and lines below the Equator represent Southern locations.
Now that we have established a system of coordinates, we can determine on a chart the position of a boat, a lighthouse, or a buoy by understanding its Latitude (the degrees, North or South of the Equator) and its Longitude (the degrees East or West of the Prime Meridian.)
Whereas on a map we would say "located at the intersection of North 3rd Avenue and West 20th Street", on a chart we would say "Latitude 25° North and Longitude 80° West." (Degrees are represented with the ° symbol.)
Degrees of Latitude can range from 0° at the Equator to 90° at the North or South Pole. Degrees of Longitude can range from 0° at the Prime Meridian to 180° at the point half-way around the globe. In practical terms, we need to increase the granularity of our coordinates, as not everything would align exactly with just the major lines of Parallels (Latitude) and Meridians (Longitude). For this reason, the units of degrees are further divided into Minutes and Seconds. There are 60 minutes between each measurement of degrees. These are divided further and there are 60 seconds within each Minute.
In our example above, let's imagine our position is actually halfway between 25° and 26° North. We would say "Latitude 25° 30' 0" North and Longitude 80° 00' 00" West. (The ' symbol represent Minutes, and the " symbol represents Seconds.) Because 30 is half of 60, it represents 25° plus half the distance to 26°.
Let's now connect this to what would be displayed on a chartplotter. We understand that degrees are used to describe the distance from either the Equator when we talk about Latitude or from the Prime Meridian when we talk about Longitude. We know that Minutes further describe the distance between degrees. And, although Seconds further breakdown the granularity of the Minutes, they are most commonly displayed as decimals of a Minute, which is the common chartplotter format.
Our example would commonly display on a chartplotter as:
N 25° 30.000'
W 080° 00.000'
In a more detailed example, let’s assume our coordinates are:
N 25° 30.050'
W 080° 03.575'
These coordinates tell us that the point is 25°, 30.050 Minutes North of the Equator. The added decimal of .05 Minutes is a very small fraction. We can safely say that the coordinate is halfway between 25° and 26° North of the Equator.
This also tells us that the point is 80°, 3.75 Minutes West of the Prime Meridian. As we will see, measurements of Minutes of Latitude can be converted to distance to provide a relative meaning to the coordinates on a chart.
Navigational Charts
It is said that the navigator that does not maintain up to date nautical charts will sooner or later find the bottom. This is certainly true today in the form of updates to both chartplotter software and electronic charts which reflect changes in navigational aids, shoaling, landmarks, bridge clearances, and other dangers to navigation.
The navigational chart is probably the most ancient of navigational instruments. It is also the most easily understood. Who hasn't, at some point, played the role of cartographer, drawing a map for someone to help guide them to a destination?
The navigational chart is the two-dimensional (flat) graphic representation of a zone on the three-dimensional (round) Earth. 250 years before the birth of Christ, the Greek mathematician Eratosthenes had concluded the Earth was round and had estimated its circumference with incredible accuracy. By the 13th century, cartographers had developed highly accurate charts of the Mediterranean, documenting the knowledge ancient navigators had acquired through their travels.
The cartographer Gerardo Mercator first realized the projection of the globe onto a flat plane and ushered in a new era of navigation. The method of projection on a paper chart or on a chartplotter still carries his name today, known as a Mercator Projection.
A Navigational Chart is defined as a scaled flat representation of a zone on the Earth's surface with the objective to facilitate navigation over waterways. Charts are a work instrument used to solve navigational problems and indispensable to travel on oceans, rivers, lakes and seas.
The chart is produced by deconstructing a globe to lay flat. As you can imagine trying to do this with a soccer ball, distortions would occur when comparing relative points. As you move towards the Poles, the flattened representation makes it seem as though Alaska, Greenland, and Siberia are much farther from each other compared to their actual position on a globe. On a flat plane, Meridians, which run North-South run parallel to each other, whereas on a globe, Meridians narrow and meet as you move from the Equator to the Poles. This anomaly can result in a longer path when a course is drawn as a straight line on a chart from one point to another. The picture below shows how the distance of a course drawn on a flat Mercator Projection known as The Rhumb Line, compares to one drawn on a globe, known as a Great Circle course.
This distortion occurs over long distances and is not a concern for the recreational boater. For long voyages, other projections are available, as well as chartplotters that automatically calculate Great Circle routes.
The top of a Nautical Chart along any Meridian is always North. This may not be consistent if the chart is reprinted in a foldable configuration and not an original NOAA chart, however alignment can be confirmed by finding the Compass Rose. Distances on the chart can be determined by finding the scale provided on the chart and are expressed in Nautical Miles.
For the recreational boater, basic knowledge of charts provides an option for planning extended cruises where visualizing a larger area is useful and to also provide a backup should electronics fail. In most coastal situations, a boater should be able to use a paper navigational chart to understand their position and determine an approximate course to a navigational aide or other waypoint to facilitate a safe return to port.
Magnetic Compass and Courses
The invention of the compass was the result of contributions from many civilizations. As far back as 20 AD, the ancient Chinese had discovered the "lodestone", a rock with magnetic properties that when hung from a string would point in a fixed direction aligned with the Earth's poles.
To express these directions, The Greeks developed a system of "points" and "winds." The Romans added versions of the Compass Rose which evolved to the 32 point cardinal rose used today. Although the history of the compass is long and interesting, our main concern is the use of the magnetic compass on a boat in order to maintain a predetermined course.
A marine compass consists of an arrow that is suspended in a manner that allows for circular movement without friction. The arrow is affixed to a circular card with tick marks representing 0° to 360° and aligned so that 0° points North. The whole assembly is encapsulated in a glass or plastic sphere and submerged in a petroleum-based liquid which slows movement and prevents freezing. The magnetic compass points to the Magnetic North which doesn't necessarily align with the Geographic or True North displayed on Navigational Charts.
Magnetic Variation
There is a difference between Magnetic North as displayed by the compass, and True North which results from the projection of the Earth onto charts. This difference exists because the actual location of the magnetic North Pole is not the same as the North Pole as defined by our system of coordinates. Not only is it not the same, but it can move over time. It is important to understand the implications of this anomaly and how it relates to the True Heading (the course heading drawn on a chart) and the Magnetic Heading (the heading adjusted for the actual location of the magnetic North pole).
The magnetic influence of the Earth varies over time and by geographic zones. This Variation is measured periodically in more than 70 locations around the world and mapped by scientists in a manner that allows navigators to include adjustments in their calculations.
When a line is drawn on a chart between two points, the navigator uses parallel rulers to transpose the course onto the Compass Rose and determine the True Heading (outer circle of the rose). For every chart, the Compass Rose will include details of the calculated Variation (inner circle). The True Heading is then adjusted by the Variation to produce the Magnetic heading. As shown below, every chart will include a Compass Rose (or two) to facilitate the use of parallel rulers.
Once the Magnetic heading is known, the navigator knows the approximate course to steer to reach the destination on the chart.
However, the heading must be further adjusted due to Deviation.
Deviation
At one time, ships were made of wood, had no motors, and had no electronic equipment that could interfere with the compass. When steel hulled ships arrived, compensating for the magnetic influence of the hull became a challenge and if it not for the work of Mathew Flinders, wooden ships may have lived on. Flinders pioneered the use of iron bars placed near the compass to counteract the Deviation caused by the magnetic influence of the hull.
Modern compasses found on recreational vessels have E-W and N-S adjustment screws that allow the user to minimize the Deviation caused by electronics or other metal components located near the compass. When Deviation cannot be eliminated, a Deviation Table records the difference between the Magnetic Heading and Compass Course (what the compass actually reads). Simply put, a Deviation Table specifies what Compass Course (Steer) should appear on the compass, to follow a desired Magnetic Heading (Magnetic).
In summary, the True Heading is adjusted +/- by the Variation to determine the Magnetic Heading. The Magnetic Heading is adjusted +/- by the Deviation to determine the Compass Course.
Direction/Heading
Course headings are expressed in degrees in a three-digit format as follows: 045°
Your chartplotter will display a heading determined by the GPS which represents the Course-Over-Ground (COG). The COG can be displayed by the chartplotter as a Magnetic or True heading and denoted as M or T next to the displayed heading. For practical reasons, it is preferred to display Magnetic headings on your chartplotter as they will more closely match your compass readings; however, it is irrelevant to using the chartplotter.
Depth
Depth measurements on charts are displayed primarily in feet and represent the average low tide reading. On larger scale charts that cover deep waters, depths may be expressed in fathoms (1 fathom = 6 feet).
The recreational boater will likely have a depth sounder or fish finder which will provide accurate depth readings. A good practice is to correlate actual depth readings with those on the chart or chartplotter as an approximate confirmation of position. If your chartplotter shows your position corresponds to 30 feet of water, but your depth finder displays that you are in 10 feet of water, this is an indicator that your vessel is not positioned where the chartplotter is indicating or there is another issue that must be resolved before continuing to navigate safely.
Distances and Measurements
The Nautical Mile is the preferred unit of distance used in navigation because it simplifies the use of charts and is directly correlated to the circumference of the Earth. If we observe the Earth at the Equator from above, we would see a 360 degree circle. This was previously described as 180 degrees from the Prime Meridian to the East plus 180 degrees from the Prime Meridian to the West, or 360 degrees. The Earth has a circumference of 21,614 Nautical Miles (NM). If we divide 21,614 by 360, we calculate that each degree, is equal to 60 nautical miles, or 1°=60 NM. We also know that there are 60 Minutes in one degree, therefore 1 Minute=1 NM.
Using our example from earlier, N 25° 30.050 represents a distance of 1,530.050 NM from the Equator. This is calculated by multiplying degrees and minutes by their known distances:
(25 X 60) + (30.050 X 1) = 1,530
And, W 080° 03.575 represents a distance of approximately 4,803.575 NM from the Prime Meridian when measured at the Equator.
(80 X 60) + (3.575 X 1) = 4,803.575
It is important to remember that degrees of Latitude can be directly converted to distance because the distance between lines of Latitude are consistent as we move from the Equator to the poles. Lines of Longitude narrow as they move away from the Equator and therefore cannot be converted to distance.
Speed
Speed is also expressed as a function of Nautical Miles and is referred to as Knots (KT). Knots are the number of Nautical Miles traveled in an hour. In navigation, speed is commonly used to determine the time needed to travel from one point to another. When planning a voyage, we usually know the starting point and distance to the destination, and we know the speed at which the vessel will be operated. Using a formula that describes the relationship between these variables, we can take V=Speed in KTs, D=Distance in NM, and T-Time in Minutes, and solve for any one variable if we have the other two.
Distance / Speed = Time
Assuming we will be travelling 135 NM at 27 KT's:
135 / 27 = 5
It would take 5 hours to complete the trip. Although this simple formula is easy to understand, why do boat trips always seem to take longer than anticipated? This is usually because it is unlikely you can run through your entire course at 27 KT's. In reality, you will encounter channels, no wake zones, weather, and other issues that will slow your average speed.
On your chartplotter, the same math above is used to calculate the estimated time to your target waypoint. Using your GPS-determined speed, Speed Over Ground (SOG), and distance to your destination, your chartplotter is constantly recalculating your time to destination.
Practical Knowledge: Use Speed, Distance, Fuel Flow to Calculate Range
One of the most basic questions a boat operator must be able to answer before leaving the dock is how much fuel will be required to safely complete the planned voyage.
Boat manufacturers publish performance data detailing the expected speed and fuel consumption for their fleet and engine configurations. In the example table, we can see the fuel consumption in Gallons Per Hour (GPH) at a given speed for our vessel.
To calculate the amount of fuel needed, we need to know:
Distance - The distance, measured in Miles, to be travelled to and from the destination.
Speed - The speed, measured in Miles Per Hour (MPH), the boat will be operated at for the majority of the voyage.
Fuel Consumption Rate - The rate fuel is consumed, measured in Gallons Per Hour (GPH), at the Speed the vessel will be operated.
Note: When using formulas that contain Speed and Distance, KT's must be used with only NM's and MPH can only be used with Statutory Miles. To convert KT's or NM's, multiply by .87. To convert MPH or Miles, multiply by 1.15. In our example, we have already adjusted for MPH/Miles which is the common format used by recreational boat manufacturers. The formula applies to either measurement.
Let's assume we have planned a round trip of 63.25 Miles, and we expect to cruise at the most efficient 31.4 MPH as shown in the table.
Step 1 - Use the Speed of 31.4 MPH and Distance of 63.25 to solve for Time using the following formula:
Distance / Speed = Time
63.25 / 31.4 = 2.01
Our trip will take approximately 2 hours to complete, cruising at 31.4 MPH.
Step 2 - We can see from the performance data table that that at 31.4 MPH, 20.6 GPH will be consumed. We can calculate the total fuel that would be consumed by multiplying the GPH by Time determined in Step 1.
GPH X Time = Fuel
20.6 X 2.01 = 41.2
Step 3 - To calculate a margin of safety, multiply 41.2 gallons by 1.5.
41.2 X 1.5 = 61.8
We should start our voyage with a minimum of 61.8 gallons of fuel.
How can we be certain we have enough fuel in the tank?
Our fuel gauge reads about 1/3 full and we know we have a 300 gallon tank. It would appear we have approximately 100 gallons of fuel remaining, so we are ready to go. STOP!
Fuel gauges on boats are notoriously inaccurate and should not be relied upon for calculating range. The best method to determine fuel level, is to know the capacity of the fuel tank and fill it to the top. Then, use the engine gauges to reset the cumulative fuel consumption to zero after fueling. From that point forward, the fuel flow will be tracked cumulatively and will display how much fuel has actually been consumed from the known starting point of 300 gallons.
Assuming the method above was followed, we can check the fuel information on our engine gauges. In the image shown, we can see 260.8 gallons have been USED from the last time the tank was filled to its capacity of 300 gallons.
300 - 260.8 = 39.2
300 minus 260.8 means only 39.2 gallons remain in the tank. We need to fuel up before our voyage.
Note: Actual fuel consumption may vary from the manufactures tables and can be adversely impacted by wind, load and current. It is important to confirm your actual fuel consumption rate through experience and adjust accordingly.
2 - Coastal Piloting
In the first chapter, we covered an introduction to various navigation topics. At this point you should have a basic understanding of the following:
How navigational charts are created and structured
How Latitude and Longitude describe a point on a chart
How headings are determined and communicated and the difference between True, Magnetic and Compass headings
How Speed, Distance, and Time interrelate
In this chapter, we will focus on utilizing a navigational chart for Coastal Piloting.
There are various instruments that are used with navigational charts to measure distance, plot courses, and complete a variety of other tasks.
Parallel Rulers are commonly used as a straight edge and to transpose a course consistently anywhere on the chart. Dividers are used to measure distances on a chart and replicate them on a distance or Latitude scale. Using Parallel Rulers and Dividers is much easier to learn though experience as their use is fairly intuitive; however, it is challenging to explain. The animated videos below will help you understand their use and application.
Determining the Position of a Vessel
The position of a boat on a navigational chart is plotted using information obtained through equipment and instruments available to the navigator as follows:
Latitude and Longitude (coordinates)
Bearings of known landmarks and waypoints
Combinations of bearings and depths
Combinations of bearings and distances
Geographic Coordinates
Latitude and Longitude represent the most widely used method for communicating position. They can be obtained through complicated methods such as celestial navigation or by using a GPS/chartplotter.
Latitude and Longitude are always expressed in a specific order with Latitude appearing first and Longitude second. This is particularly important when communicating over radio where interference may exist. The listener can assume the first set of numbers will be Latitude and the second Longitude. Furthering the point of clear communication, coordinates should be read as single numbers. For example, N 25° 30.050' - W 080° 03.575' should be read as:
Two Five Degrees, Three Zero decimal Zero Five Zero Minutes North
Zero Eight Zero Degrees, Zero Three decimal Five Seven Five West
Plotting a Given Position on a Chart - Latitude and Longitude
Assume we are provided a known position at:
N 27° 34.000'
W 82° 46.000'
Latitude, which runs vertically across the chart, is measured along the vertical edge of the chart displaying a scale as shown here.
The bottom right corner of the chart starts at Latitude 27° 29.000'. If we move up the edge we will cross the 30' interval until you reach the 34' mark which is not labeled but marked at point < . This mark represents the line of Latitude across the chart corresponding to the position of the vessel.
Longitude is measured along the bottom or top edge as shown below. Although not visible below, the 82° is to the right, and we have scrolled our view to the left to visualize the 45' shown below, and the 46' marked at point < . Because the position is West of the Prime Meridian, the number increases along the bottom of the chart from right to left.
We now want to intersect the two lines from their respective points on the vertical edge and bottom in order to plot the location on the chart. This can be done using a parallel ruler and a pencil to draw intersecting lines.
The point of intersection shown above is referred to as a Fix.
Bearing of Known Landmarks and Waypoints
Let's assume that we want to further confirm our position above, or we are starting without a given set of coordinates. By using a handheld compass, a navigator on the vessel can obtain bearings of visible known objects that are also represented on the navigational chart. By tracing a line through the known chart location of the object using the recorded compass bearing from the handheld compass, the navigator can establish a Line of Position (LOP). By using at least two LOP's, the navigator can establish or confirm a Fix.
In this example, the bearings of two known locations, the "Lookout" and "Passage Key" were recorded using a handheld compass from the vessel. The bearings were transferred to the chart on the Compass Rose using the Magnetic bearing. The line was then transferred using Parallel Rulers from the Compass Rose to a position intersecting the observed object on the chart. The intersection of the two red lines corresponded with the given location and confirmed our position.
Bearing and Depths
As shown in the previous example, Lines of Position are plotted on a chart to establish the position of a vessel. Two or more points with perpendicular LOP's are preferred to establish an accurate position. When only one bearing to a known point is available, the LOP can be combined with a depth reading under the vessel to estimate the position. If we take our previous example, let's assume that only the "Lookout" position is available at a bearing of 10° from the vessel. We know the position of the vessel is somewhere on the LOP (red line) drawn at 10° to the "Lookout." Let's assume our depth sounder shows the depth under our vessel is 21 feet. We can assume from the depths shown on the chart along the LOP, that the vessel is located near the center or North edge of the channel shown.
Bearing and Distances
Bearings can also be combined with speed to approximate position. In the case where a vessel starts from a known position and follows a specific course and speed, if time is tracked we can use our formula Distance = Speed X Time to calculate the distance traveled along the course line and approximate the vessels position. This is known as a Dead Reckoning.
Plot a Course
Now that we know where our vessel is located, we can plot a course to another destination, waypoint, anchorage, etc. We connect plotted courses together to construct routes.
Starting with our known position, we would like to plot a course through the center of the Sunshine Skyway Bridge into Tampa Bay. Take the parallel rulers and draw a line from our current position to the center span of the bridge. Review your course line to ensure the path can be navigated safely by your vessel and no hazards are present. Review any waypoints for reference you may encounter along the way. Use the parallel rulers to determine the course heading from the starting point to the destination by transposing the course line drawn to the Compass Rose. Record the course on the chart and denote the heading with T for True or M for Magnetic. True is generally the more accepted practice for recording headings as they will not change with time, however, for convenience, the Magnetic course can also be noted on charts. Below we show a blue course line to our destination bearing 62° T.
Using dividers, we can determine that the distance to the center span is 6.63 NM. We plan to travel at a speed of 10 KT's. Knowing Time = Distance / Speed, we determine the voyage should take only .663 hours or 40 minutes (60 X .663).
The following animated video provides an example of how to plot a course.
Practical Knowledge: What do you do when your chartplotter malfunctions?
Chartplotters are susceptible to a number of interruption risks including vessel electrical failure, device issues, screen breakage, or GPS issues. If using a multifunctioning device, this may affect depth sounder, radar, tide displays, engine monitoring and other integrated functions. There are several options that may allow you to continue your voyage; or at a minimum return to familiar waters safely.
Mobile Phone Based Navigation Apps
There are a number of mobile apps that function as a chartplotter and will provide position, routes, bearings, etc. Assuming there is not a GPS outage, many of these mobile apps such as Navionics or Active Captain (Garmin), can provide all the tools needed to navigate safely. Be sure that your mobile app of choice has downloaded the charts for the area you will be navigating and is not reliant on cell/data connection to fully function.
Paper Charts As you have learned, paper charts can function to replace your chartplotters functions. However, it may be impractical to start using parallel rulers and dividers in a recreational motor vessel. You may be better prepared if you have paper charts with your most common routes already denoted on charts with headings, bearings, etc.
The practical reality is that you can use paper charts to simply estimate your position and relative directions and bearings to assist in navigating safely to more familiar waters. However, you must be aware that small errors in heading result in larger errors as you travel longer distances.
You now have a basic understanding of how charts are used for navigation, but actually using charts to plot accurate courses and positions requires formal instruction and hands-on training. There are a number of resources and training programs to prepare the competent navigator.
3 - Aids to Navigation
It is likely that aids to navigation are as old as navigation itself. If we think about an early navigator travelling on a river in a canoe carved from a hollowed-out tree, it is likely that he would have marked a dangerous shoal using a primitive marker in order avoid repeating the accident that led to its discovery. As navigation advanced, aids to navigation developed quickly to guide ancient ships that could travel over greater distances. The Lighthouse at Alexandria is likely one of the most ancient large scale navigational aids, built over 2,200 years ago and one of the seven marvels of the ancient world.
In the United States, there are more than 40,000 aids to navigation ranging from lighted buoys, radar reflecting towers, and channel markers. Without them, navigators visiting unfamiliar ports would find it difficult to find channels and anchorages or avoid dangers. Navigation Charts detail the exact location of aids to navigation and facilitate their usage and identification. In the United States, aides to navigation are designed, constructed and maintained by the United States Coast Guard.
Aids to navigation are based on a "lateral" system, where markers are primarily situated on the edges of navigable waterways. The system consistently follows an orientation to and from ports where red markers are always to the right of the vessel when returning to port. This has created the easy to remember mnemonic: "red, right, return."
When markers are numbered, the system attributes even numbers to red and odd numbers to green markers. Numbering begins with the start of a channel and increases in number towards the destination (marina, port, anchorage, etc.) When lighted, a marker will have a corresponding-colored light matching its base color. To further help distinguish markers at night, lighted markers will have predetermined flashing patterns which are denoted on charts. Using a digital watch, timer or a watch with a second hand, the interval between flashes can be used to confirm a lighted buoy's identity. The characteristics of a marker are described on charts via the sample abbreviation system shown here.
On a chart, the abbreviations appear adjacent to a marker. In this example, the system is used to describe a Flashing Red 4 Seconds 16ft 5 Mile Range aid with a number "70" designation.
In addition to basic aides, there are a number of additional lateral and non-lateral markers used on navigational charts.
Intercoastal Waterway
Along the Atlantic and Gulf Coasts of the United States, it is possible to navigate from Texas to Maine via relatively secure and protected waterways through a network of rivers, estuaries, and lakes known as the Intercoastal Waterway (ICW). Although the ICW uses a lateral system of aids to navigation, it is not possible to utilize a "return to port" orientation to establish a consistent placement of markers. The ICW uses an orientation system relative to the destination: if traveling from Maine to Texas, red markers will appear to the right (starboard) of the vessel and green markers will appear on the left (port) of the vessel. The opposite will apply to vessels travelling from Texas to Maine. This applies regardless of the compass heading.
When leaving the ICW, the normal positioning logic applies. For example, leaving the ICW via a channel ending at a marina, the beginning of the marina channel will likely be marked by a green marker numbered "1". Red markers will mark the right edge of the channel and be to the port side of the vessel following the familiar "red, right, return." Green markers will mark the left edge of the channel.
It should be noted that ICW markers have an additional yellow reflective square (green markers) or triangle (red markers) to help identify that they are part of the ICW system and therefore follow the aforementioned positioning logic.
Practical Knowledge: Working with Aids to Navigation
Visual confirmation of markers is a key safety consideration when navigating. Chartplotters make spotting markers easier because the bearing of the aid relative to the heading of the vessel make it clear as to where to look. It is important to avoid visually misidentifying markers and straying off the intended course.
When plotting a course on a chartplotter, choose major waypoints and aids to navigation that are easily identified. These include "1" markers and larger buoys and towers. The size and visible range of an aid is identified on a chart in feet and miles as shown.
Avoid routes that cut directly to markers inside channels even if the depths are adequate for the vessel. These markers are more likely to suffer damage during storms and are less likely to be replaced quickly relative to markers at the beginning of the channel and can be harder to identify.
Once a marker is identified that correlates to the chartplotter course and target waypoint, it is easier to use the visual marker on the horizon as a navigation target when compared to steering a course via the chartplotter. While steering to a visual target, the chartplotter should continue to be checked to ensure the target waypoint is the correct one.
4 - Rules of the Road
As an operator of a recreational motor vessel, you are constantly in a state of multi-tasking. When underway, the operator is maintaining a course either guided by aids to navigation, a compass heading, and/or chartplotter. And, at the same time, the operator is scanning for other vessels or dangers, keeping an on eye on passengers to ensure they are safe, and monitoring vessel systems.
To simplify the decision-making process when encountering another vessel, a system of rules has been developed to promote safety and avoid collisions.
The Rules of the Road govern how boats interact with each other to determine which boat is the Give Way Vessel and which boat is the Stand On Vessel. The Give Way Vessel is the vessel that will "give way" and allow the other to continue on its current course. It is equally important to know when you are the Give Way Vessel or the Stand On Vessel, as the action of each operator works simultaneously to ensure safety.
The most frequent encounter an operator will face is a Crossing Situation, and it is the easiest to understand and navigate safely. The first responsibility of the operator is to identify the direction of the other vessel and which side of the approaching vessel is facing the operator.
In the example to the left, boat B is traveling right to left, and the Port side of the boat is exposed to boat A's operator. In many aspects of boating, Port is represented with the color red and Starboard is represented with the color green. The operator visualizing the Port side of the approaching boat (in this case boat A) should correlate this view with RED which is easily interpreted as AVOID. Boat A is the Give Way Vessel and would slow and/or turn to avoid a collision. If we assume that we are the operator of boat B, we view the approaching boat A and determine that we are seeing the Starboard side of the vessel which correlates to GREEN. Green is easily interpreted as GO. Boat B is the Stand On Vessel and would continue on its course. When navigating at night, the vessel's red and green navigation lights coincide with the color scheme described.
As the two vessels approach, it is important for the Give Way Vessel to clearly make a turn in order to provide a visual communication to the Stand On Vessel operator that they have clearly understood their role as the Give Way Vessel. The Stand On Vessel should also communicate their understanding of their responsibility by maintaining a steady course and speed.
Another common scenario particularly in a channel, is a Head-On Situation. In this situation both vessels must take care to remain "Port-to-Port", meaning each vessel will leave the other on their port side. Each operator will see the Port (RED) side of the other boat indicating each operator is "giving way" and avoiding the course of the other. In an Overtaking situation, where one vessel is passing another vessel, the passing vessel is by default the Give Way Vessel and must only pass with extreme caution avoiding any potential interference with the vessel being passed.
In all situations, certain vessels have priority and are always considered the Stand On Vessel as follows:
Vessels not under command
Vessels restricted in their ability to maneuver
Vessels constrained by draft
Fishing vessels engaged in fishing, with gear deployed
Sailing vessels (under sail)
Practical Knowledge: When to Break the Rules
Although the Rules of the Road prevent millions of accidents every day, collisions do occur. As an operator, you may need to make a decision that goes against the rules in order to avoid a collision or to choose a safer path.
If you are approaching a vessel operating in an erratic manner, you may decide to avoid the encounter by slowing down or turning away, even if you are the Stand On Vessel.
You may encounter a vessel whose operator has no knowledge of the Rules of the Road and appears to believe he is the Stand On Vessel regardless of the scenario. It may be safest to avoid a vessel crossing scenario.
When two vessels are approaching an intersection point at almost the same heading, the Give Way Vessel operator's visibility and awareness may be limited particularly if the Stand On Vessel is travelling at a higher rate of speed and approaching from behind. In the interest of safety, the vessel furthest from the intersection point should turn behind the slower vessel and avoid the approaching crossing situation.
5 - VHF Radio Communication
Today's boaters have a variety of communication devices available for communication within coastal waters. In most areas, once a vessel is a few miles offshore, only VHF or Satellite communication will be available to communicate to coastal stations. The minimum standard for marine radio communication is a VHF marine radio. A VHF radio can be used to communicate with other vessels, marinas, the Coast Guard, or any other VHF marine radio. VHF range is limited to "line-of-site" between the transmitter antenna and the receiving antenna. As shown below, this is greatly influenced by the height of the transmitting and receiving antenna and their relation to the curvature of the Earth.
In addition to standard analog radio wave communication, a current marine VHF radio will also support DSC (Digital Selective Calling) which supports digital communication and enhances range and clarity, and reduces cross-talk on crowded channels. Depending on your location, the range of your VHF marine radio's ability to communicate to the US Coast Guard will be mostly dependent on the height of the Coast Guard radio tower. Below is an example of Coast Guard Sector St. Petersburg, and the estimated DSC coverage areas.
DSC has several advantages in a distress situation including the ability to send an unmanned distress signal to the Coast Guard by pressing the red distress button located on all VHF radios that support DSC. The distress signal will include the Latitude and Longitude of the vessel if the VHF has an embedded GPS unit or is connected to the boat's chartplotter.
DSC also enables direct calls to other DSC equipped VHF radio's using an assigned MMSI (Maritime Mobile Service Identity) number that works almost like a phone number.
To fully utilize the benefits of the marine VHF communication, a vessel operator should be familiar with the proper usage of their VHF radio and be proficient as follows:
Initiate a DSC distress signal
Issue a Mayday call to the US Coast Guard
Hail the US Coast Guard for non-emergency purposes
Hail Tow Boat US or other tow service
Communicate with marina or other marine service resources
Hail other vessels using normal channels and MMSI/DSC
Listen to NOAA weather broadcasts
VHF Radio Tests
Boaters travelling further than 10-15 miles offshore, should consider an EPIRB (Emergency Position Indicating Radio Beacon) or PLB (Personal Locator Beacon). Both devices use satellite communication to relay distress and location information to the Coast Guard. In addition, some PLB products can send text messages and non-emergency location updates.
Practical Knowledge: Making Sure Your VHF Works
A VHF radio is a critical piece of safety equipment that is often located in exposed areas and must be tested regularly to ensure proper functionality. There are two testing methods each with their own benefits and drawbacks.
Method 1 - Traditional Radio Check
The traditional radio check is simply a request on a shared channel for a reply from another VHF user. Although traditional checks are frowned upon by those concerned with overcrowding shared channels, there simply is no other effective means to test the analog capabilities of the VHF radio.
A traditional radio check should be performed on Channel 9, 68, 69, 71, or 72, and should not be requested on Channel 16. The validity of the test depends on your location relative to the person responding to your broadcast. A successful test with someone nearby does not necessarily mean the VHF is capable of communicating at a distance of 10 miles or greater, for example.
A valid check should be conducted as follows:
Tune to the preferred channel
Use the "Lo" (1-Watt) power setting for initial testing
Key the mic, "radio check, radio check, this is "Boat Name" in "General Location”
Wait for a reply and request further information regarding the location of the responding party if it is not initially provided
By completing this initial test, you have confirmed the functionality of the microphone, the transmitter, the receiver and antenna connection. It is useful, particularly if you venture offshore, to test your VHF while at a greater distance using a higher power setting and determining the distance to a responding vessel or station.
Method 2 - DSC Radio Check
Use your VHF's DSC capability to perform a test of the DSC functionality. Per the USCG, DSC based testing can be conducted as follows:
"For VHF DSC radios equipped with the Test Call feature, test transmissions should be made to the US Coast Guard MMSI 003669999 to receive an automated VHF DSC test response. You must use the “Test Call” category of your radio because “Individual” category calls to this address will not receive an automated response. For older radios not having a test call capability, testing can only be performed by using a routine individual call to their Maritime Mobile Service Identity (MMSI)."
The following video demonstration was performed on a Standard Horizon HX890. Although testing should work on any DSC capable device on any channel, is it advisable to use channel 70 as this is a dedicated safety channel and will produce an audible confirmation in addition to an acknowledgement message on most devices.
Although many people advocate the use of DSC based testing only, it doesn't test all the capabilities of the device including the analog and microphone functions.
The bottom line, if you really want to test the full functionality of your VHF radio, it is best to perform both a Traditional Radio Check and a DSC Radio Check.
6 - Tides, Winds and Waves
Understanding the conditions one is likely to face when navigating is a key element to ensuring the safety of the vessel and passengers. Mobile devices, satellite, and radar have brought a multitude of resources to the recreational boater to help avoid adverse weather conditions. In this chapter we examine how to use these resources most effectively.
Tides
Tides are often overlooked by the recreational boater as the cruising limitations of their vessels are generally not a function of their draft. However, tides have an impact on a number of recreational boating concerns.
Anchoring
When anchoring in shallow water or "beaching" a vessel, boaters can be surprised by how quickly an outgoing tide can render a vessel immovable. The current and predicted tide level should be known prior to anchoring or beaching and, in a falling tide, monitored to avoid issues.
Traversing Passages and Inlets
Tidal movements produce currents which become accentuated when water in inland areas rushes out through inlets and passages on the outgoing tides. When combined with offshore winds and waves, adverse conditions can occur. In the case of many inlets that are known for potentially dangerous conditions, the worst can generally be avoided by understanding the tide tables and navigating on the incoming or slack tides.
Swimming Activities Swimmers can easily be overcome by tidal currents which can occur in waters near inlets, keys, sandbars, etc. A seemingly calm area ideal for swimming during a slack tide (the time between tidal direction change) may change as the tidal flow increases.
Tidal information can be found on a multitude of devices but often most conveniently on the vessel's chartplotter. It is important to verify the location of the Tidal Station to ensure it corresponds with the vessel's future location.
The steeper the curve depicting the tide becomes, the greater the current during the given tidal period. The period of minimal current corresponds to the peaks and valleys as the tide changes direction.
Winds and Waves
When looking for a marine forecast, boaters should focus on the marine forecast for the zone in which they will be navigating. Forecasts are only a prediction of conditions and are usually not updated to reflect current conditions. It is critical for boaters to check forecasts, current conditions, and trends in conditions. When in range, mobile devices are great resources to access NOAA and other real-time meteorological stations. Comparing the actual conditions to the forecast, a boater can potentially identify conditions that may be worse than predicted or are worsening. When out of range, satellite weather services or weather stations on your VHF radio can provide real time readings from meteorological stations.
7 - Anchoring
As with sails and oars, the anchor may be one of the most basic and ancient tools developed by mariners. Primitive anchors where simply stones that attempted to hold vessels in place by their sheer mass. The iron age allowed Roman designers to shape anchors into effective forms that could hold a much larger vessel in place relative to their size. Many variations in design have followed however the goals of any anchor are the same: hold the vessel in place under varying conditions including storms.
Recreational boaters are always in search of anchor improvements that provide adequate holding power with minimal weight and handling ease. In the interest of safety, it is always preferable to have extra holding power in order for the anchor to perform in more extreme conditions, keeping the vessel safe and secure.
To select the right anchor setup for a particular boat, the operator must take several factors into consideration:
Vessel specifications and characteristics
Type of bottom
Conditions most likely to be encountered: tides, currents, wind
Armed with these variables, marine supply stores are the best resource for advice on selecting the best anchor, chain, and rode (line) combination for your needs.
Depending on your intended usage, anchors can be narrowed down further or combined as follows:
"Lunch Hook" - This is often the name given to the main anchor on a recreational vessel. It is easy to handle and often appropriate for a protected anchorage. In recent years, many vessels as small as 20 feet are equipped with a windlass which allows for a heavier and larger anchor to be used as the main anchor, which contributes to safer anchoring.
"Storm Anchor" - It may be appropriate to equip a vessel with a larger storm anchor as a second anchor, that has greater holding power and can be used when anchoring in deeper water, in storm conditions or overnight.
"Stern Anchor" - In many areas, it is popular to anchor near beaches, with the main anchor in deeper water and the vessel held nearer to shore via a stern anchor. The stern anchor is generally lighter weight and easily handled as it may need to be carried to shore.
The process of safe and effective anchoring is basically the same for almost all vessels.
Approach an anchoring location and understand the bottom characteristics, wind and current conditions.
Prepare the anchor by ensuring that the free end of the anchor line is secured to a cleat and that the anchor line and chain are free to run out without snagging.
The vessel should be steered into the wind and advanced forward to the point where the vessel's anchor is intended to be lowered. The vessel should have ample room downwind (astern).
The anchor should then simply be lowered and, as the vessels begins moving with the wind, line should be further payed out in a controlled fashion, preferably with a half turn around a cleat. If needed, the boat can be moved back under power.
Depending on the depth, the amount of line should be payed out 7:1. For example, if anchoring in 10 feet of water, 70 feet of anchor line should be payed out. This ratio is known as the "scope."
As the line approaches approximately 2/3 of the intended scope, stop paying line out by securing the line to the cleat. This will "set" anchor.
Ensure the anchor has "caught" and pay out the remaining scope.
Do not allow swimmers in the water until the engines are off and the operator has confirmed the boat is secure.
The vessel operator should ensure the anchor is properly secure by observing the vessel's movements at anchor. This can be accomplished visually relative to other boats or landmarks or by observing the vessels "tracks" on the chartplotter. As reviewed earlier, the vessel operator can use a hand bearing compass and record bearings to landmarks. If the vessel is secure, the bearings will remain constant.
Practical Knowledge: Anchoring, Tides and Weather and Keeping Passengers Safe
When approaching a location to anchor for an afternoon swim, the vessel operator will generally observe the following:
Location and Orientation of Other Vessels
Usage of Bow and Stern Anchors
Observing where and how other boaters have anchored will give the operator an indication of local conditions and practices that should inform decision making. Equally important is to observe where other vessels are not anchored which may indicate where currents make anchoring and swimming unsafe.
The observed situation should be correlated with tide charts, currents, wind and weather forecasts to determine the safest anchoring location and method.
In a falling tide situation, the bow anchor should be deployed with a greater amount of line (scope) so that the vessel can be repositioned away from shallower water easily as the tide falls, and still maintain effective scope.
If the forecast calls for increasing wind, it may be necessary to choose a more protected location, deploy longer scope, or use of a storm anchor.
If anchoring in a slack tide, be aware how the conditions will change once the current increases or changes direction. In any condition where current is expected, a ring buoy should be deployed on a rope astern to provide swimmers with a safety resource.
It is important for the vessel operator to be aware of the location of swimmers and inform them of the expected conditions.
A stern anchor can be deployed in protected waters to keep the boat positioned consistently and easily accessible to swimmers. If it is observed that other vessel are using stern anchors, such as on a beach or sandbar, it may be important to follow suit as vessels will shift differently with wind changes if they have differing anchoring techniques.
8 - Knots
On a recreational vessel, there are a variety of ropes employed for various purposes such as docking, anchoring, or securing items on deck. When a rope is used for a specific purpose, it is called a line. There are many knots that may be useful on a boat but a mariner only needs to learn a few to be proficient on a recreational vessel.
Cleat Hitch
Use a Cleat Hitch to secure lines to cleats on the vessel or dock.
Clove Hitch
Use a Clove Hitch to secure lines from the vessel to pilings.
Bowline
Use a Bowline for a secure loop knot.
9 - Safety
As the operator of recreational vessel, you are responsible for your safety and the safety of your passengers, and to ensure that the vessel does not present a safety concern to fellow boaters. This applies to the operation of the vessel during normal circumstances and during times of distress.
A fundamental starting point is to properly equip the vessel with the required safety equipment and to ensure all the equipment is in proper working order.
The requirements for a specific vessel are determined by federal and state authorities and, are dependent on the size of the vessel. The Coast Guard chart below provides a list of minimum required safety equipment by vessel size.
In addition to the federal requirements above, there may be additional state requirements or qualifications. (Please consult your state's online resources.)
The list presented above represents the MINIMUM requirements, but there are many additional safety equipment options that can greatly enhance vessel safety.
VHF Marine Radio
A vessel should be equipped with a VHF marine radio. Although cellphone coverage is generally functional in coastal areas, a VHF marine radio ensures communication to the Coast Guard and other marine assistance resources. As an additional precaution, many operators also have a second handheld VHF marine radio as a backup.
First Aid Kit
Injuries are not uncommon in a boating environment and first aid resources are often hours away. A marine First Aid Kit provides basics items to address cuts, stings, scrapes, and other common injuries sustained in a marine environment.
Anchor
Although an anchor is not usually listed as a piece of safety equipment, it may become extremely important in certain scenarios. In the event of engine failure, it is important for the vessel to be adequately secured in a safe location. From a safety perspective it is critical to have a properly sized and effective anchor onboard.
Knife
A knife can be used to cut away rope or line from a fouled propeller or free a swimmer from an entangled cast net. A blunt tipped marine knife has a number of applications and should be readily available to the vessel operator.
EPIRB's and PLB's
EPIRB's (Emergency Position Indicating Radio Beacon) were once considered necessary only on larger vessels that ventured offshore and out of VHF marine radio range. As technology has advanced and lower priced PLB's (Personal Locator Beacon) entered the market, satellite-based rescue beacons have become a viable option for recreational vessels even if they remain near shore.
Conclusion
Boating represents a great opportunity for enjoyment and sharing in the vast natural resources available to us. To ensure a safe experience, the operator must be knowledgeable and practiced in the techniques and methods presented, and must understand their responsibility to their passengers, fellow boaters and the marine environment. A vessel operator must be competent, cautious, and prepared. In the words of Anne Morrow Lindbergh, "the sea does not reward those who are too anxious, too greedy, or too impatient."
About the Author
Captain Francisco J. Labarta was born January 25, 1929 in Havana, Cuba. Island life gave him an early exposure to the sea where he learned to sail and race in his early teens.
His desire to understand how things work and to solve problems, lead him to attend Pennsylvania Military College where he graduated with a degree in Industrial Engineering.
After a successful career in engineering sales, Captain Labarta's affinity for the sea returned and he pursued a second life teaching, chartering, and managing yachts.
One of his greatest talents was communicating complex technical topics to less experienced seafarers and instilling in his students a sense of respect and duty to enjoy and share our waterways in a manner that would preserve their use for future generations.
He would be pleased that his writings and ideas are shared here and may help mariners today and in the future.