Lessons

General

Aids to navigation include lighthouses, beacons, buoys, towers, floating aids and permanent structures. These are all man-made devices that can be used to warn of a danger, to mark a location, or to indicate a safe route. Aids to navigation are...

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Lighthouses and beacons

A Lighthouse is a major structure equipped with a light on top, with particular characteristics of the light that vary from lighthouse to lighthouse. The structure has distinctive color, shape and specified height . Many lighthouses are equipped...

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Lists and corrections

To become acquainted with the latest significant changes to lights and fog signals, e.g. light vessels, light structures, light buoys, etc., you have to consult the List of Lights and Fog Signals or the Yachtsman’s Almanac. These...

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Bouys

Buoys are floating aids to navigation. They may have the shape of a cone, can, pillar, spar or sphere, have numbers or letters or both. They have a distinguishing color, and a top mark if any, and they also have a characteristic light. They may...

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Buoyage system 1

There are two major types of buoyage systems: the lateral system and the cardinal. In the Lateral system the buoys indicate the port and starboard boundaries of a route to be followed e.g. a channel. The Lateral system differs between buoyage...

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Buoyage system 2

Other Buoys that are used to indicate isolated dangers, having navigable water around them, are known as Isolated Danger Buoys. Buoys used to indicate the location of navigable water surrounding their position, e.g. middle channel, are known as...

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Calculating luminious range

Calculating the Luminous range of a light. Let’s say the nominal range of light “X”, extracted from the Yachtsmans Almanac is 20 nautical miles, and the existing visibility is 11 nautical miles. What we want to find out here is...

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Basic characteristics

To use a light as an aid to navigation, you first have to see it and secondly you have to identify it. In the nautical chart it is symbolized by a purple exclamation point and/or by a purple circle. The basic identification characteristics are...

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Period of light

The period of a light is given in seconds and is timed from the first flash of a cycle until the first flash of the next cycle. For example, on the chart we see a lighted navigation aid, and written near the purple exclamation point is Gr. Fl.(4)...

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Light phase 1

The Light phase is the sequence or pattern of the light shown, within one complete cycle. We have the following common patterns: Fixed (F.): this light shines with a steady and unblinking intensity Flashing (Fl.): the duration of darkness is...

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Light phase 2

Isophase (Iso.): the duration of darkness is equal to the duration of the light at any length of cycle. Group flashing (Gp.Fl.): in this cycle there is a combination of two or more groups of flashes in one cycle at regular intervals. For example...

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Light categories

The lights used as aids to navigation are divided into two main categories: the major lights and the minor lights. The major lights are subdivided into two groups: the primary major lights and the secondary major lights. The primary major lights...

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Types 1

There are 3 types of lights used as aids to navigation: Alternating lights, Sector lights, and Range lights. Alternating lights are used when great caution is required, for example when entering a harbor. The light alternates color, for example...

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Types 2

Range lights are used to indicate a safe passage inside channels, and recommend a course where navigational hazards are present on both sides. Usually they come in pairs and are situated in such a way that one shows over the other when they are...

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Types of anchors

Make sure that you carry at least two anchors, one as an everyday anchor that is stowed at the bow in the anchor locker, and one as a storm anchor. The characteristics of the boat and the type of sea bed – sand, shale, mud, gravel –...

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Before anchoring 1

When you are selecting an anchoring position, make sure that it is sheltered from the wind and waves, and away from ship or boat traffic. Check the chart to determine the depth where you wish to anchor, and calculate the amount of cable you...

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Before anchoring 2

Before anchoring among other vessels, consider your boat’s swinging circle. When the wind shifts or the current changes, your boat will swing bow to the wind or current, whichever is stronger. Try to anchor your boat near boats of similar...

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