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| Natural Gas |
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Short for compressed natural gas or CNG. A type of compressed gas used as fuel for stoves and heaters. CNG is stored in metal cylinders prior to use. CNG is considered safer than other types of fuel such as propane (LPG) because it is lighter than air and may rise into the sky in the event of a leak. Caution should still be used as CNG can collect near the cabin ceiling, potentially causing an explosion. Propane is available in more areas around the world than CNG so CNG is not often used outside of North America.
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| Nautical |
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Having to do with boats, ships, or sailing.
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| Nautical Almanac |
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An annually published book that contains information about the position of the sun, moon, planets and stars. This information is used for celestial navigation.
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| Nautical Mile |
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Distance at sea is measured in nautical miles, which are about 6067.12 feet, 1.15 statute miles or exactly 1852 meters. Nautical miles have the unique property that a minute of latitude is equal to one nautical mile (there is a slight error because the earth is not perfectly round.) Measurement of speed is done in knots where one knot equals one nautical mile per hour. A statute mile is used to measure distances on land in the United states and is 5280 feet.
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| Navigable Water |
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Water of sufficient depth to allow a boat to travel through it.
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| Navigation |
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The act of determining the position of a boat and the course needed to safely move the boat from place to place.
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| Navigation Lights |
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Lights on a boat help others determine its course, position and what it is doing. Boats underway should have a red light visible from its port bow, a green light on the starboard bow and a white light at its stern. Other lights are required for vessels under power, fishing, towing, etc.
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| Navigation Rules |
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The rules concerning which vessel has the right of way if there is a possibility of collision between two or more boats. The United States Inland Rules of the Road and International Rules of the Road are slightly different.
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| Navigational Aid |
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Any fixed object that a navigator may use to find his position, such as permanent land or sea markers, buoys, radiobeacons, and lighthouses.
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| Navigator |
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The person responsible for navigating a boat.
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| Neap Tide |
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The tide with the least variation in water level, occurring when the moon is one quarter and three quarters full. The lowest high tide and the highest low tide occur at neap tide. The opposite is the spring tide.
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| Noon Sight |
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A sighting taken for celestial navigation at noon, when the sun is at its highest point in the sky.
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| North |
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One of the 4 cardinal compass points. North is the direction toward the North Pole and is at 0° on a compass card.
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| North Pole |
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The "top" point of the line about which the earth rotates.
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| North Star |
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Polaris, the North Star, is visible in the northern hemisphere and indicates the direction of north. In the southern hemisphere the Southern Cross is used to find the direction of south.
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| Notices to Mariners |
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Official notices reporting changes to charts and other navigational and safety items.
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| Nun Buoy |
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A conical buoy with a pointed top, painted red, and having an even number, used in the United States for navigational aids. At night they may have a red light. These buoys should be kept on the right side of the boat when returning from a larger body of water to a smaller one such as a marina. Can buoys are used on the opposite side of the channel. Also see green and red daymarks.
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