• Using this precision marine hand bearing compass, you can easily obtain quick magnetic bearings on shore or floating objects. Simply align front and rear sights on an object and reading off bearing.
• Uses include quick bearing or position set, determination of angular gain or loss on the competition while racing, checking distance offshore, establishing lee-bow set while cruising or racing in currents, drift vectoring and plotting a line of position.
• Features a liquid-damped compass card graduated in 5° segments and a large, contoured handle. Lanyard and instructions included.

• Answers the need of every sextant user who cannot depend on a natural sea horizon. Use for backyard practice, finding exact position when inland, and making exact sextant shot on foggy mornings. To use, fill with water and read the angle of the reflected sun with your sextant. Half your sextant reading is the sun’s angle above the true horizon. Windproof and corrosion resistant, the reflecting surface is completely enclosed.
• Comes with two sun shades, a lid and full directions. Compact 6″ × 4″ × 1½″ (15 × 10 × 4 cm).

• A simplified, yet complete Celestial Navigation system. Includes everything you need: sextant use and corrections, starfinder for 18 stars, data entry form, and step-by-step sight reduction and plotting procedures.
• May be scored and separated; large portion fits in the sextant case for quick reference, and small part acts as a waterproof data reduction card.
• Measures 8½ × 11 inches (22 × 28 cm).

• Shows the use of wind direction, barometric pressure, and cloud type in predicting the weather, plus a full list of radio weather stations for official broadcasts, key information on storm warnings, hurricane avoidance, navigating in fog and other hazardous conditions, and more.
• Weatherproof high-strength plastic, full color both sides. Punched for binder or bulkhead mounting. Dimensions: 8.5″ x 11″ (216 x 279 mm).

• Covers all the basic procedures and equipment. Includes predeparture checklist, recommended equipment & spare parts, fueling procedures, engine troubleshooting, radio use, trailering, launching, anchoring, knot tying, water-skiing hand signals.
• Gives rules of the U.S. Buoyage System and right-of-way. Helps in emergencies by covering distress signals, fire procedures, towing, weather warnings, and first aid (hypothermia & CPR).

• A comprehensive guide incorporating the International Maritime Buoyage System and COLREGS.
• Clarifies differences between Cardinal and Lateral buoyage systems and buoyage regions, key to reducing confusion and danger when entering unfamiliar waters or busy harbors. Complete details on right-of-way, sound signals, entering and clearing a foreign port, lights and day shapes, collision prevention procedures and signal flags.
• Measures 8½ × 11 inches (22 × 28 cm).

• All the piloting information you need at your fingertips: dead reckoning basics, true and magnetic compass relationships, position finding, estimating distance off, current and leeway corrections.
• Measures 8½ × 11 inches (22 × 28 cm).

• A proven navigation tools used by the US Coast Guard, US Coast Guard Auxiliary and US Power Squadron. Navigation Rules feature US. Buoyage System, inland and international rules, right-of-way, lights, sound signals and bridge signals.
• Measures 8½ × 11 inches (22 × 28 cm).

What Are the Navigation Rules?

The navigation rules are designed to help avoid a collision at sea. The information contained on the Navigation Rules Card is that which is considered critical to safe passage for all vessels. There are 72 rules in all that were developed by the Intergovernmental Maritime Consultative Organization (IMCO), which was later renamed to the International Maritime Organization (IMO).

The rules of navigation are similar to the rules of the road when driving a car. They are meant to provide consistency so everyone can work to help avoid a collision. There are many nuances to the rules that must be understood before operating a craft. The most important rule is known as “Rule 7,” which addresses what to do when the risk of collision is present. Determining whether a risk of collision exists is key: the prevailing weather and circumstances can be used to determine if a risk is present. If in doubt, it is always suggested that you act as if the risk is present. Knowing these rules is the first step to the safe operation of your vessel.

What is the Most Important Navigation Rule?

Three rules are considered the most important to help prevent collisions. The first is that at a bare minimum, you should have a proper lookout. The second is that you should always operate your vessel at a safe speed. The third is that you should always give right-of-way when in doubt.

It is always suggested that you follow these rules, but if a collision is imminent, it is acceptable to break them if it means avoiding an accident. Safety and protecting human lives should always come first. You should also use a compass to check the bearing of any neighboring vessel. This means checking them frequently because they can change bearings, and you must be continually vigilant. You should also be able to recognize when you are the stand-on or give-way vessel. It is always the duty of the give-way vessel to avoid a collision.

• This model has many great features including seven large sunshades, a 3 mm × 27 mm star scope, and easy-to-read micrometer drum vernier scale that reads to 2/10 of a minute. The Mark 15 has a 7″ (18 cm) frame radius graduated from 120 degrees to –5 degrees and comes with a traditional half-silvered mirror.
• Comes with instruction booklet.

Are Sextants Still Used Today?

The sextant was first used in 1731. In recent times, they have been used to backup electronic navigational systems. In 2016, the Chief of Naval Operations and U.S. Navy ordered that crewmen should be trained to use the sextant as a backup navigational device in case of power failure. It is always considered a good idea to have a sextant and know how to use one in case of navigational instrument failure. When you are ready to buy sextant instruments for your craft, Davis Instruments is known for its quality.

How Does a Sextant Work?

The sextant uses two mirrors to measure the distance between objects. One of the mirrors only has silver on half of it to allow some light to pass through. This half-silver mirror is used to look at the horizon. Meanwhile, the second mirror is attached to an arm that moves. This mirror is moved to a position where the sun’s reflection also reflects onto the first mirror. When you view this through the eyepiece, you see the sun superimposed on the horizon. The angle can then be read using the scale at the bottom of the sextant. You can use any two objects to do this.

What is a Sextant Used to Measure?

When a sextant is used to estimate the angle of a celestial object and the horizon, it is called sighting the object or taking a sight. The angle and the time when the measurement was taken are used to determine the position on a nautical chart. For instance, you can shoot the sun at noon or Polaris at night to estimate your latitude.

A sextant can also be used to measure the distance of an object using its height, and it can be used to measure the angles between two objects to obtain the position on a chart. Another use of the sextant is to shoot the moon and another object to determine Greenwich Mean Time and longitude.

• The top-of-the-line Davis plastic sextant, the Mark 25 features our Beam Convergerâ„¢ mirror, sometimes referred to as a “full horizon mirror.” A special coating is applied to high quality optical glass to allow the user to see through this mirror, yet still pick up images as faint as low-light stars.
• The Mark 25 is illuminated by a long-life LED and made of an upgraded plastic that is very stable.
• Comes with instruction booklet.

Are Sextants Still Used Today?

The sextant was first used in 1731. In recent times, they have been used to backup electronic navigational systems. In 2016, the Chief of Naval Operations and U.S. Navy ordered that crewmen should be trained to use the sextant as a backup navigational device in case of power failure. It is always considered a good idea to have a sextant and know how to use one in case of navigational instrument failure. When you are ready to buy sextant instruments for your craft, Davis Instruments is known for its quality.

How Does a Sextant Work?

The sextant uses two mirrors to measure the distance between objects. One of the mirrors only has silver on half of it to allow some light to pass through. This half-silver mirror is used to look at the horizon. Meanwhile, the second mirror is attached to an arm that moves. This mirror is moved to a position where the sun’s reflection also reflects onto the first mirror. When you view this through the eyepiece, you see the sun superimposed on the horizon. The angle can then be read using the scale at the bottom of the sextant. You can use any two objects to do this.

What is a Sextant Used to Measure?

When a sextant is used to estimate the angle of a celestial object and the horizon, it is called sighting the object or taking a sight. The angle and the time when the measurement was taken are used to determine the position on a nautical chart. For instance, you can shoot the sun at noon or Polaris at night to estimate your latitude.

A sextant can also be used to measure the distance of an object using its height, and it can be used to measure the angles between two objects to obtain the position on a chart. Another use of the sextant is to shoot the moon and another object to determine Greenwich Mean Time and longitude.