Nacodah. Master of an Arab dhow ('Nakhoda'). Nadir. Point in heavens diametrically opposite zenith. Nail Sick. Minor leaks caused by erosion of nails in a wooden hull. Name of Ship. That name appearing in her certificate of registry

N - English Maritime terminology

Nacodah. Master of an Arab dhow ('Nakhoda').

Nadir. Point in heavens diametrically opposite zenith.

Nail Sick. Minor leaks caused by erosion of nails in a wooden hull.

Name of Ship. That name appearing in her certificate of registry. Is cut or punched in her bow and stern.

Nanoplankton. Minute sea creatures and plant that float in clusters on surface of sea.

Napier's Curve, Diagram. Curved line drawn on a specially designed diagram and passing through a limited number of points on which deviation of compass has been ascertained. This facilitates the determination of deviations on points for which no observa­tion has been made.

Napier's Rules of Circular Parts. Diagrammatic arrangement of five parts, or their complements, of a right-angled or quadrantal spherical triangle, the right angle or 90° side being disregarded, in five sections of a circle. If these be put in the rotation of their occurrence, an unknown part can be found from the other parts; the rule being that sine of middle part equals product of tangents of adjacent parts, or product of cosines of opposite parts.

Narrow Channel Rule. Rule of Collision Regulations. Requires a vessel navigating a narrow channel to keep to that side of mid-channel that is on her starboard hand.

Narrows. Areas where navigable waters become narrow due to shoals or adjacent land.

Narrow Seas. Seas as distinguished from oceans. Seas having no great breadth. At one time, was especially applied to English Channel.

Narrow Waters. Areas in which navigable waters become narrow due to shoals or land.

Narwhal. Member of the whale family. Male has left tusk devel­oped into a spiral horn, 6 to 10 ft. long, right tusk being rudi­mentary. Were formerly met with around 80°N, and hunted for their excellent oil.

Natural Draught. Furnace draught arising from height of funnel above that of furnace, and from temperature of furnace gases.

Natural Projection. One in which lines of sight are directly pro­jected to a plane. Used when distinguishing this projection from an artificial projection.

Natural Scale. One in which the delineation of a charted area is directly proportional to the area charted.

Nau. Seeder

Naufrage.* Shipwreck.

Naufragate.* To shipwreck. To wreck a ship.

Naulage.* Freight, passage money or ferry charge.

Naumachy. Naval battle, sea fight. Representation of a sea fight.

Nauropometer. Instrument for measuring inclination or heel of a ship.

Nauscopy. Art of discovering the approach of a distant ship to the land.

Nausea. Sea sickness. Originally meant 'ship sickness'.

Naut. Depth unit of 1000 fathoms. Used only in cable laying work.

Nautical. Pertaining to ships, seamen or navigation.

Nautical Almanac. Annual volume, published by the Admiralty, giving astronomical information essential to navigation. First issued 1767.

Nautical Astronomy. Astronomy as applied to navigation.

Nautical Day. Day, formerly used at sea, commencing with Sun's noon transit. Abolished in Merchant Navy, January 1, 1925, but abolished in Royal Navy several years before. Nautical Distance. Length of rhumb line intercepted by two positions.

Nautical Dromometer. Early 19th century towed log invented by

Benjamin Martin.

Nautical Mile. Length of arc of F of meridian in latitude of position of measurement. Value varies between 6046.4 ft. in Equator and 6107.8 ft. at Poles. A standard of 6080 ft. (1853.18 m), correct for Lat. 48°, is used in log registrations and practical navigation. The International Nautical Mile = 1852 metres, correct for Lat. 44 ½ °. Sea Mile. Nautical School. Educational establishment in which navigation, seamanship and other subjects connected with shipping are I taught.

Nautical Tables. Book containing tabulated data - arithmetical, geometrical, astronomical and geographical—for use in navigation.

Nautical Twilight. Interval between Sun being 6° below visible horizon and 12° below it. Horizon is sufficiently distinct for sextant use, and bright stars are observable.

Nautilus Propeller. Water jet discharged astern from a submerged orifice for propelling purposes in a boat. Is uneconomical in use but is retained in some lifeboats where risk of propeller being fouled is likely to arise.

Nautophone. Electrically-operated instrument that sounds a high note as a fog signal. Naval. Pertaining to ships, or to a navy.

Naval Architecture. Science and practice concerned with design, building and fitting of ships, and with the investigation of the forces acting upon them in a seaway, and in specific circum­stances.

Naval Cadet. Student for officer rank in Royal Navy.

Naval Court. Consists of three to five officers of R.N., consular officers, or masters of British ships. Convened abroad only by an officer commanding H.M. ship or by Consul, when necessary to investigate charges against master, officer or seaman of a British ship; when a British ship is lost or abandoned; when interests of owner make it advisable.

Naval Crown. Device showing stern and square sail of a ship, alternately, on a fillet or circle.

Naval Discipline Act. Act of Parliament governing the conduct of men and officers of Royal Navy. First introduced 1661.

Naval Lines. Lines going across a reefing topsail, from leech to leech, on after side, to secure reef line. Secured to upper eyelet holes of reef cringles.

Naval Officer. Commissioned or subordinate officer in Royal Navy, or in a foreign navy.

Navel Futtock. Ground futtock in midship timber of a wooden ship.

Navel Hood.* Timber immediately above hawse pipe of wooden ship.

Navel Pipe. Large tube through which cable goes from deck above locker to cable deck.

Navicert. Certificate of Destination for Specified Cargoes, issued by governments in wartime.

Navigability. Of a vessel, capability of being controlled and steered. Of a water area, capability of being navigated.

Navigable. Capable of being safely navigated.

Navigable Semicircle. That half of a cyclonic depression in which there is no risk of encountering the vortex. Is left-hand semi­circle in N Latitudes and right-hand semicircle in S latitudes.

Navigate. To direct and control a ship. To pass from one place to another by ship.

Navigation. Art and science of conducting a ship from one place to another. Sometimes used in a limited sense to restrict it to conducting by celestial observations and methods. 2. Canal made for passage of ships, barges and boats.

Navigational Planets. Four planets -Venus, Mars, Saturn, Jupiter - whose positions are precisely tabulated, in Nautical Almanac, for navigational purposes.

Navigational Stars. Selected bright stars whose positions are pre­cisely tabulated in Nautical Almanac for navigational purposes.

Navigation Laws. Laws passed, at different times, to regulate, restrict or encourage shipping and shipborne trade. First English code is of time of Richard I. See 'Laws of Oleron.'

Navigation Lights. Those lights compulsorily shown by vessels at sea, in accordance with international rules.

Navigator. Person skilled in the art and practice of navigation. A person in charge of navigation of a ship. Specialised officer appointed to a ship for navigation duties. Name was given, formerly, to a man employed in digging canals (navigations), hence 'navvy'. 'Navigator shovel' is a relic of latter use of name.

Navigator's Yeoman. Rating, trained in chart correction, who works under orders of navigating officer of H.M. ship.

Navis Aperta. Undecked Roman ship.

Navis Tecta. Decked Roman ship.

Navivium.* Early type of submerged log on paddle-wheel principle. Way of ship acted on lower half of paddle, causing it to rotate and actuate inboard-registering gear. Early 19th century. Navy. The shipping of a country when considered collectively. The war vessels of a country when considered collectively. The personnel of a navy when considered collectively.

Neap. Applied to the tides of small amplitude occurring about the time of Moon being in quadrature.

Neaped. Said of vessel when she grounds at high water when tides are decreasing from spring to neap. Also applied to a vessel unable to leave a tidal harbour through decrease of high-water height of tide.

Neap Tide. Tidal undulation that has the highest low water, and the lowest high water, in the series. Occurs about time of quadrature of Sun and Moon.

Necklace. Open link chain secured around wooden mast of a sailing ship to take lower eyes of futtock rigging.

Needle. Magnetised bar that provides directional property of a

magnetic compass.

Nef, Nau. Term for a ship in about 17th century, from Latin 'Nans' = ship.

Negative. Opposite of 'positive'. 2. Annul, or cancel, a signal or order.

Negative Slip. Term used when vessel's progress through the water is greater than that due to propulsive action of propeller. May be due to indraught of a following wake.

Negligence Clause. Inserted in a contract to relieve one of the - contracting parties from responsibility for loss due to negligence of a third party who may, or may not be, a servant of the contracting party.

Nelson Room. Room at Lloyd's, in London, containing several valuable and important mementoes of Admiral Lord Nelson.

Nemedri. 'North European and Mediterranean Routeing Instruc­tions.' Contain routeing instructions to enable vessels to avoid passing through mined areas.

Nephoscope. Instrument used for determining direction and speed of clouds.

Neptune. God of the sea in Roman mythology. Son of Saturn. 2. Eighth planet from Sun. Discovered by Adams (England) and Leverrier (France) at about the same time. Has one satellite. Orbital period, 164.79 years.

Neptune Log. Towed log of Cherub type, but constructed to register speeds of 18 knots and upwards.

Nereids. Nymphs of the sea, daughters of Nereus and Doris. 2. Sea centipedes.

Ness. Projection of land into sea; headland; cape. Nets. Fishing-nets. Torpedo-nets.

Nettles. Halves of two yams twisted together to make another yarn. 2. Lengths of nettle stuff used for attaching clews to hammocks.

Nettle Stuff. Superior type of spunyarn consisting of either two or three yarns laid up together. Used for gaskets and similar fittings, and for hammock clews in R.N.

Nett Tonnage. Ship measurement derived from gross tonnage by deducting spaces allowed for crew and propelling power; 100 ft. of space being reckoned as one ton.

Neutral Axis. That line, in a girder or other member under stress, separating the tensile and compressive components of the stress.

Neutral Equilibrium. As applied to ship, is that state of flotation in which she will have neither righting nor capsizing moment if moved. In mechanics, is that equilibrium that does not alter with displacement of the body.

Newel. Vertical timber to take tenons of rails going from breast­work to gangway.

New Moon. That phase of Moon when she is in conjunction with Sun and reflects no light towards Earth.

New Style. Used when indicating dates reckoned by Gregorian Calendar that was introduced into England, September, 1792, but was not adopted universally.

Nickey. Large Manx fishing boat similar to a Cornish lugger used in 19th century.

Night Glasses. Binoculars with large light-gathering power, but with small magnification—about 2 ½ diameters.

Nimbostratus. Cloud form characterised by uniform grey, low-lying sheet. Usually coincident with steady rain or snow.

Nimbus. Rain- or snow-cloud. Usually of grey colour, and com­bining stratus, cumulus, and cirrus.

Ninepin Blocks. Rack containing nine sheaves, through which running rigging is rove. 2. Blocks with upward projections from top and bottom of metal stropping. Fitted between two hori­zontal metal rails into which projections fitted and allowed sheave to swivel. Placed in vicinity of mast.

Nineteen-Metre Type. First international type of yacht (1911). Length overall 95 ft., L.W.L. 62-3 ft. Beam 17 ft. Sail area 6850 sq. ft. Reg. tonnage 60. T.M. tonnage 100. Freeboard 4 ft. 6 in.

Nineteen -Yearly Period. As 18-61 years is the period in which Moon's nodes make a circuit of Ecliptic, it follows that heights and times of tidal undulations repeat, approximately, in this period.

Nine-Thread Stuff. One-inch cordage having nine threads in each strand.

Nip. Short turn in a rope. 2. To secure a rope by seizing, trapping or racking. 3. To confine by clamping. To Freshen the Nip is to move a rope slightly so that a different part bears upon a fairlead or sheave.

Nipa Palms. Creeping plants found in tidal estuaries of Ganges and other East Indian rivers. Frequently impede navigation.

Nipped. Said of a vessel when pressed by ice on both sides.

Nipper. To nip a rope or cable. 2. Person who nips or nippers. 3. Length of rope by which hemp cables were attached to messenger. 4. 'Bullivant's Nipper.'

Noah's Ark. Vessel, mentioned in Bible and in Chaldean history, in which Noah rode out a flood. Dimensions were (about): length, 450 ft.; breadth, 75 ft.; depth, 45 ft. Built of cypress wood and had three decks.

Nobby. Manx fishing boat, dandy rigged, named from its first builder, Clarke of Peel.

Nock. Forward upper corner of four-sides fore and aft sail. Also spelt 'knock'. More usually Throat'.

Noctilucent Clouds. Luminous cirriform clouds, travelling at high speed, occasionally seen about midnight after summer solstice.

Nocturlabium.* The 'Nocturnal' instrument.

Nocturnal. Pertaining to night. 2. Early 16th-century instrument used for determining latitude by observations of Polaris. Had a base plate, graduated for time and date, on which was a disc graduated in arc. When inner disc was set to time and date the instrument was suspended vertically and a pointer, pivoted at centre of disc, was sighted on Polaris. Pointer then indicated altitude of Pole. Invented 1520.

Nocturnal Arc. Arc above horizon described by a heavenly body during hours of darkness.

Nocturnal Radiation. Outgoing radiation of heat from Earth to space during hours of night.

Nodes. Those points in Ecliptic where orbit of Moon or planet, cut it. Termed 'ascending' node if body crosses in N'ly direction, and 'descending' if in S'ly direction.

Nodical Month. Interval between successive passages of Moon through the same node. Value is 27 d 05 h 05-6 m.

Nog. Treenail in heel of a shore supporting a ship on the slip.

Nogging. Driving treenails in heel of shore.

'No Higher.' Injunction to helmsman, when under sail, not to come closer to the wind.

Nolloth's Ship Clinometer. Hinged instrument with one arm clamped athwartships, in ship's horizontal plane, and one arm pivoted. By sighting horizon along movable arm the angle of roll can be read on a graduated arc.

Non-Harmonic. When applied to tidal data and methods, denotes those values and methods based upon, or derived from, observa­tion and experience, and not from harmonic analysis or methods.

Non-toppling Block. Ballasted pulley-block used in lower end of a purchase to ensure that purchase can be rounded up without block capsizing.

Noon. That instant when true or mean Sun is on the meridian of a place. Named 'apparent' or 'mean', according to the Sun considered.

Norfolk Wherry. Large flat-bottomed craft with mast stepped well forward. Carries a large, loose-footed gaff sail abaft mast. Met with on Norfolk Broads and in the vicinity.

Normal Centre (of Earth). That point, in Earth's axis, at which a vertical line passing through an observer would meet the axis.

Normal Latitude. Angle between plane of Equator and a vertical line passing downwards through an observer.

Normand's Formula. Introduced by M. Normand, in 1882, to calculate 'Inch Trim Moment' from area of waterplane, length of load waterline, beam and volume of displacement.

Norman Heads. Shaped extremities of cross piece of wooden bitts. Used for taking turns with ropes.

Normans. Short lengths of shaped timber put into sprockets of capstan to take turn of a rope that has been led to capstan for heaving. 2. U-shape irons put over whelps of capstan to prevent riding turns in hemp cable.

Norte. Cold N'ly wind in Gulf of Mexico.

North. Cardinal point of the compass. The direction of that pole of Earth at which an observer would note that direction of Earth's rotation was towards his left hand.

North Easter. Gale blowing from a NE'ly point.

North East Monsoon Current. Ocean current caused by NE monsoon in Arabian Sea. Sets S along Malabar coast and then SW'ly to African coast, where it meets a northerly stream from Zanzibar. Then sets E'ly across Indian Ocean.

North East Passage. Navigable waterway, between Atlantic and Pacific Oceans, that passes along north coast of Europe. Dis­covered by Nordenskiold in 1878-9.

Northern Signs. Signs of Zodiac north of Equinoctial. They are those from Aries to Virgo, both inclusive.

Northern Waggoner.* Old name for constellation Ursa Major.

North Following. In or towards the N to E quadrant of the compass. Formerly used in connection with a pair of observed stars that had not reached the meridian.

Northing. Distance, or latitude, made good in a N'ly direction.

North Pole. Northern extremity of Earth's axis of rotation. North pole of Equator, or Equinoctial.

North Preceding.* In or towards the N to W quadrant of compass. Formerly used in connection with a pair of observed stars that had crossed the meridian north of observer.

North Star. Star Polaris a Ursae Minoris.

Notary Public. Public official who is authorised to take statements on oath, and who keeps a record of all statements so made.

'Nothing Off.' Injunction to helmsman to keep ship's head close to wind, and not let it fall to leeward.

Notice of Abandonment. Formal surrender, by owner, to under­writers of policy on an insured ship that is a constructive total loss. Is a prerequisite to payment of insurance.

Notice of Readiness. Written notice, given by Master or agent of an arrived ship, stating ship's readiness to load and approximate amount of cargo required. Delivered to shipper or his agent.

Notice to Mariners. Periodical, or casual, notices issued by Hydrographic Department, or other authority, regarding changes in lights, buoys, and other navigational aids; alterations in charted information; menaces to navigation and other matters of importance and urgency to shipping and navigation.

Noting a Bill. The recording, by a notary public, that a Bill of Exchange has been presented but not accepted.

Noting Protest. Making a statement under oath in the presence of a notary public, and before the full implication of the matter protested is known. By reserving the right to 'extend', the Protest can be amplified as relevant information becomes available.

Not Under Command. Said of a vessel when, through some accident, she is not fully under control while under way.

Ntepe Dhows. Remarkable craft once built at port of Lamu. They had no stem or sternposts and planking was sewn together with coir twine. They were remarkably weatherly and fast - but very wet.

Nuclear Power. Power derived from nuclear fision which generates heat used to produce steam. Chief advantages are that large quantities of bunkers need not be carried and (for submarines) no fresh air is consumed.

Number. Flag hoist that indicates a vessel's name.

Nunatak. Isolated rocky peak rising from a sheet of inland ice.

Nun Buoy. Buoy having the shape of two cones, base to base.

Nut (of Anchor). Key piece, on stock, that fits in slot in shank and prevents stock from turning.

Nutation. A 'nodding' of Earth's axis during a period of 18 years 220 days. Caused by variation in the Lunisolar gravitational pull on Earth's equatorial bulge - the variation being due to Moon's maximum declination varying between 18° 18' and 28° 36' in the period. Pole of Equinoctial describes a small ellipse about its mean place. The value of nutation is I8 ½ ¢¢ of arc, that is 9 ¼ ¢¢ above or below its mean value.

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