Introduction to Navigation Part 4 Getting to Know Your Magnetic Compass

You may have noticed, if you have looked at a nautical chart, that there were two rings on the compass rose. The outside ring is based on true north and the 000° direction points to the true North Pole. On the inside ring labeled “MAGNETIC” the  000° direction points in a different direction than the outside ring.

These basics are covered in the online Nautical Know How Basic Boating Safety Course at http://boatsafe.com/navigation .

The difference between True and Magnetic is called “Variation.” Variation is a naturally occurring disturbance caused by the magnetic north pole. Variation will change depending on where you are located on the earth. If you are operating on the West Coast of the US you will have east variation because the magnetic north pole is located east of you. On the East Coast of the US you have west variation because the magnetic north pole is west of your location.

Another error which may show up in your magnetic compass is called “Deviation.”  Magnetic compasses are also affected by magnetic fields on the vessel itself. Just put some sort of ferrous metal such as a screw driver next to your compass and you will see an example of this error.

Significant errors of deviation could be caused by metal tanks, your engine, metallic objects near your compass or even electromagnetic interference caused by your radio.

To safely and accurately navigate from one position to another it is important to be able to correct for both “variation” and “deviation”  and be able to steer a course by your magnetic compass.

If you want to learn more about the magnetic compass and how to calculate TVMDC…READ MORE.

Introduction to Navigation Part 3 Definitions

The following navigation terms are used in most recognized navigational texts. Learning and understanding what they mean will give you a head start on the information that is to be presented in later chapters. Don’t worry about memorizing all these at this time. You will get plenty of exposure to these terms as you advance through the course.

These basics are covered in the online Nautical Know How Coastal Navigation  Course at http://boatsafe.com/navigation .

Piloting is defined as the determination of the position and the direction of the movements of a vessel. This involves frequent or continuous reference to landmarks, aids to navigation, and depth sounding.

Direction is the orientation of an imaginary line joining one point to another without regard to the distance between them. Direction is measured in angular units of arc, measured in degrees, from a common reference whether it be true north or magnetic north. The usual reference is true north. The division of the degree may be either minutes and seconds or decimal fractions. Direction is written with three digits as in 000°.

Distance is the separation between two points without regard to direction. In navigation it is measured by the length of a line on the surface of the earth from one point to the other. It may be measured in units of yards, nautical miles or kilometers. The nautical mile is commonly used by navigators. The international nautical mile is 6076.12 feet. This is approximately 1.15 longer than the statute mile used on land.

Time is written as four digits in a 24 hour system; four minutes after midnight is 0004, 9:32 AM would be written as 0932 and 1:16 PM would be written as 1316.

Speed is defined as the rate of movement, and in navigation is usually measured in nautical miles per hour, or knots. The time element is included in the definition of “knot”; the use of knots (kts) per hour is incorrect. Speed is represented on your chart as “S”. Example S = 7.5 kts.

Dead Reckoning (DR) is the projection of a present position to an anticipated future position. This is done by using a previous known position and applying known direction, speed and distance covered. The term comes from deduced reckoning which was abbreviated ded reckoning. DR plots are done at a minimum of every hour or when ever you change course or speed. A new DR plot line is started each time a new “known position” is found.

Course is the direction of travel through the water or the direction a vessel is to be steered or is being steered. The course may be designated as true (T), magnetic (M), or compass (C). Course is always written in three digits and is followed by the abbreviation of its source. Example C = 090° T

Bearing is the direction of any place or object from a given point. It may be designated as true (T), magnetic (M), compass (C) or relative (R). It is always written in three digits and is followed by the abbreviation of its source. Example B = 270° T

Heading is the direction the vessel points or heads at any instant as read from your compass. It is always written in three digits. Example HDG = 270°

Fix is a known location at a specific time based on verifiable information and carrying a high degree of accuracy. Example:  0900

Running Fix is a known location at a specific time, with a lesser degree of accuracy than a fix. It is based on information obtained from a single event at two different times and plotted as a common time. Example:  R Fix 0900

Electronic Fix is a fix obtained from one or more electronic devices. Example:  0900

Introduction to Navigation Part 2 Nautical Charts

Today is the second of a series of articles about Navigation. You can advance your Navigation Know How by participating in the Nautical Know How Coastal Navigation Course.

These basics are covered in the online Nautical Know How Basic Boating Safety Course at http://boatsafe.com/navigation . It is highly recommended that, prior to beginning this advanced Coastal Navigation Course, each student successfully complete the Basic Boating Safety Course.

Nautical charts are different from maps in that they specifically depict water areas while maps concentrate on land area, roads, landmarks, etc. Land areas and features on charts are sketchy and are noted only for their interest to the Navigator. Unlike maps, the nautical chart conveys much information specifically designed to assist in safely navigating the area that the chart covers.

Chart Scaling

 The scale of a chart is expressed as a ratio such as 1:80,000. This could also be represented as the fraction 1/80,000. This means that one unit on the chart represents 80,000 of the same units on the earth. The terms “small scale” and “large scale” can be confusing if you haven’t studied fractions recently. The denominator of the fraction (the number under the line) is the number that changes as the scale of the chart changes. The larger the denominator  the smaller the fraction. For instance 1:80,000 is smaller than 1:40,000, so the larger the denominator the smaller the scale of the chart. That is, a 1:80,000 chart would be a small scale while a 1:40,000 would be a large scale.

 Chart Colors

The major water areas are not colored and retain the white color of the paper itself. Shallow water areas, shown in light blue and light green, indicate shallows that are uncovered at some stage of the tide, such as marsh areas.

 Small objects such as buoys and markers are shown in a magenta color. Because charts are used at night under red light (to keep from impairing night vision) the color magenta shows up best at night and in the day.

 Buoys and dayboards that are actually red are indicated in magenta. Green buoys and dayboards are shown in green.

Lighted buoys, regardless of their color, are shown with a magenta dot over the small circle portion of the chart symbol. Cautions, symbols noting danger, compass roses and recommended courses are also noted in magenta.

For more about the Nautical Know How Coastal Navigation Course…READ MORE.

Introduction to Navigation

Today starts a series of articles about Navigation. We will give you a list of skill sets required to become a “real” navigator and also give you the opportunity to advance your Navigation Know How by participating in the Nautical Know How Coastal Navigation Course. This course will give you step-by-step instructions on how to navigate safely from one point to another. It teaches you to take into consideration all effects including set, drift, tides, currents, etc. that might hinder you along the way.

These basics are covered in the online Nautical Know How Basic Boating Safety Course at http://boatsafe.com/navigation . It is highly recommended that, prior to beginning this advanced Coastal Navigation Course, each student successfully complete the Basic Boating Safety Course.

Navigation can be divided into four primary classifications:

• piloting
• dead reckoning
• electronic navigation
• celestial navigation

The problems that you, as a navigator, must solve are as follows:

1. How to determine your position.
2. How to determine the direction in which to proceed to get from one position to another.
3. How to determine distance and related factors of time and speed as you proceed.

Of these three problems facing every navigator, the most basic is that of locating your position. Unless you know your position, you cannot direct the movements of your vessel with any accuracy, safety or efficiency.

You will need to have, and learn to use, several navigation tools. Although there are many tools at your disposal at any marine store, the following are the minimum necessary:

•  dividers
• parallel rulers
• right angle triangle (optional, but handy)
• charts
• pencils
• hand bearing compass
• steering compass
• watch or chronometer
• log and time-keeping note paper
• calculator, abacus or fingers & toes

More Navigation Rules Series – Narrow Channels and Special Situations

Navigating Narrow Channels

When operating in a narrow channel, the rules tell you to stay as far to the outer limit of the channel as practical on your starboard side.

Boats less than 20 meters (65 feet) long, or a sailboat, shall not impede a boat that is constrained by draft, i.e. a large ship that must operate within the channel in order to make way safely. When crossing a channel, do so at a right angle and in such a way as to avoid causing the traffic in the channel to make course or speed changes.

Do not anchor in a narrow channel.

Special Situations

When operating on the Great Lakes, Western Rivers and other designated rivers, the down bound boat (going with the current) has the right of way over a boat going upstream. This is because a boat going upstream can maneuver better than a one going downstream.

Additionally, a boat crossing a designated river shall keep out of the way of boats ascending or descending the river.

If you approach a bend in a river around which you cannot see, sound one prolonged blast to alert boats approaching from the other side of the bend that you are there. If another boat is around the bend, it should answer with one prolonged blast. Conversely, if you hear a prolonged blast as you approach the bend, answer with a prolonged blast.

More Navigation Rules Series – Commercial Vessel Situations

If at all possible, stay out of areas where there is commercial vessel traffic such as shipping lanes or traffic separation zones. Large ships and barges have special problems in maneuvering and cannot and will not get out of your way.

Think about it, even with an elevated bridge, when you are looking out over a deck that may be the length of a football field there is a cone of invisibility area a certain distance in front that can not be seen. In that area you will also be invisible to the radar.

In addition a fully loaded ship, even going at a relatively low-speed, may take miles to come to a complete stop.

Just remember it is not a good idea to “tangle with a tanker.”

If you must operate around commercial vessels, take heed of the following:

• Avoid ship channels. If you must cross, do so at right angles and as quickly as possible.
• Be alert. Watch for traffic.
• Be seen, especially at night.
• Know the sound signals, especially the danger or doubt signal.
• Keep your VHF radio tuned to channel 16 and listen carefully.
• Order all aboard to wear PFDs.
• Be familiar with the area and have current navigation charts.
• Don’t be a non-survivor of a collision with a large ship.

More Navigation Rules Series – Overtaking Situations

When two vessels are moving in the same direction, and the astern vessel wishes to pass, it must initiate the signal to pass as shown in the diagram. The vessel passing is the give-way vessel and should keep out of the way of the vessel being passed. The vessel being passed is the stand-on vessel and must maintain its course and speed. If the stand-on vessel realizes that the course intended by the give-way vessel is not safe, it should sound the danger or doubt signal.

A vessel is deemed to be overtaking when the vessel is approaching the vessel ahead in a direction of 22.5 degrees abaft her beam. At night you would only be able to see the stern light of the vessel being overtaken. You would not be able to see either sidelight.

Inland Rules”I intend to pass you on your port side” 2 short blasts (1 sec.)”Agreement” 2 short blasts (1 sec.)International Rules:”I intend to pass you on your port side” 2 prolonged blasts/2 short “Agreement” 1 prolonged/1 short/1 prolonged/1 short

Inland Rules”I intend to pass you on your starboard side” 1 short blast (1 sec.)”Agreement” 1 short blast (1 sec.)International Rules:”I intend to pass you on your starboard side” 2 prolonged blasts/1 short “Agreement” 1 prolonged/1 short/1 prolonged/1 short

If you are the overtaking vessel, remember that you are the give-way vessel until well past, and safely clear of, the passed vessel. Do not cut in front, impede or endanger another vessel.

More Navigation Rules Series – Crossing Situations

When two power driven boats are approaching at right angles or nearly so, and risk of collision exists, the boat on the right is the stand-on vessel and must hold its course and speed. The other boat, the give-way vessel, shall maneuver to keep clear of the stand-on vessel and shall pass it by its stern. If necessary, slow, stop or reverse until the stand-on vessel is clear.

In the example above, the red vessel is the give-way vessel and should alter course and speed to pass behind the blue vessel. If the skipper of the blue vessel does not observe the red vessel taking action to avoid collision, then he/she must take the required action to avoid a collision.

Sailing Craft and Vessels Propelled by Oars or Paddles

Sailing craft (not under power) and boats propelled by oars or paddles are stand-on vessels when approaching power driven boats. In this situation, the power-driven boat should alter course to pass behind the sailboat.

An exception to this is if the sailboat or self-propelled watercraft is passing a power driven vessel. In an overtaking situation, the overtaking vessel is the give-way vessel, even if it is not propelled by an engine.

More Navigation Rules Series – Risk of Collision

Every means available shall be used to determine if risk of collision exists. This could be information from your lookout, radar, or other means. If there is any doubt as to the risk of collision, you should act as if it does exist and take appropriate action.

In determining if risk of collision exists, the following considerations shall be among those taken into account:

• Risk of collision shall be deemed to exist if the compass bearing of an approaching vessel does not appear to change
• Risk may sometimes exist even when an appreciable bearing change is evident, particularly when approaching a very large vessel or a tow, or when approaching a vessel at close range.
• If necessary to avoid collision or allow more time to assess the situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion.
• When maneuvering to prevent collision, do so early and make the maneuver large enough to be recognized the other vessel. Small alterations of course and/or speed should be avoided.

When two power driven vessels are in sight of one another and the possibility of collision exists, one vessel is designated by the rules as the stand-on vessel and the other is designated as the give-way vessel. The stand-on vessel should maintain its course and speed. The give-way vessel must take early and substantial action to avoid collision.

If it becomes apparent that the actions taken (or not taken) by the give-way vessel are dangerous or insufficient, the stand-on vessel must act to avoid collision.

So, how do you know a risk of collision exists? An example: your boat and another boat are on a course with a constant bearing but a decreasing range. You are both heading to the same point at the same speed. The risk of collision exists if neither of you alter course and/or speed.

For a graphical view of constant bearing and decreasing range go to: http://boatingbasicsonline.com/content/general/6_2_b1.php

A Better Way to File a Float Plan

Have you ever been guilty of taking the boat out somewhere remote without telling someone where you’re going and when you’ll be back? Most of us have. Sometimes we even felt guilty for doing so. We all know we should file a float plan before leaving the dock, but the prospect of writing out a plan on a piece of paper, or a template download from the internet, then distributing it to our trusted contacts just seems so, well… antiquated.

There is a better way. Float Plan Registry (http://floatplanregistry.com/) is a free float plan management and automatic overdue notification system for boaters.

With Float Plan Registry, you create an online profile containing your vessel, crew, and emergency contacts. With all your data stored in your secure online profile, you can create and distribute a float plan in seconds using their float plan wizard tool. When you publish your float plan, it is automatically delivered to your contacts by email. A link in the email allows your contacts to view your float plan online. Any changes you make to your float plan are immediately available to your contacts without having to redistribute the plan.

Your vessel profile contains all the relevant information about your boat needed for a float plan including vessel type (power or sail), make, model, year, color, fuel type, HIN, registration number, coastguard documentation number, home port, etc. There’s even a section to add your own detailed vessel description to highlight other unique features about your boat. You can even upload a picture of your boat. All your detailed vessel information is automatically included in any float plan you create.

Your crew list contains vital information about your crew members including name, age, and contact information. You can designate a default set of crew members you normally have aboard so that they are automatically included in your float plans.

Your contact list contains contact information for your emergency contacts – those you want your float plans and overdue notices delivered to. Here again you can define a “default” set of contacts that will automatically be included in your float plans.

Float Plan Registry’s float planning wizard allows you to create two types of checkpoints: passive checkpoints, which do not require a check-in and are simply an informational part of your itinerary, and “active” checkpoints, which are actively monitored by the system to ensure a check-in status is received. Check-in reminders are automatically emailed to you for all active (required) checkpoints that are part of a float plan. The check-in process even allows you to snooze or cancel a checkpoint! In the event that you fail to provide a check-in status for a required checkpoint, your contacts are automatically notified. Try that with your passive paper-based float plan!

Using Float Plan Registry, you can create and share online float plans in seconds. The float planning wizard will automatically include your default vessel, crew, and contacts while also allowing you to choose others from your profile while building a float plan. A guest list is also available to enter information about people aboard that are not part of your crew. When a float plan is published, your contacts are automatically notified and provide a link so they can review your plan online. Changes to your float plan, including check-in status updates and check-in comments are immediately visible to your contacts. The automatic check-in reminder system will remind you to check-in when required. And the automatic overdue notification system will automatically notify your contacts if you are considered overdue for a checkpoint. A vast improvement over the analog paper-based float plan!

To learn more about Float Plan Registry, visit http://floatplanregistry.com/, or try the demo at http://floatplanregistry.com//demo.