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.
Nantucket Sleigh Ride – A term Nantucket whalers’ used to describe a whaleboat’s wild tow by the harpooned whale until it tired and was subdued.
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.
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.
Narrow-Band Direct Printing (NBDP) – Automated telegraphy, as used by the NAVTEX system and telex-over radio.
Narrows – Areas where navigable waters become narrow due to shoals or adjacent 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.
National Marine Electronics Association (NMEA) – USA organisation defining the standards interfaces of marine electronics.
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 – See ‘Needle’
Naufrage – Shipwreck. (French).
Naumachy – Naval battle, sea fight. Representation of a sea fight. (French).
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. It is an all encompassing word for anything concerning sailors or maritime travel.
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 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 1′ 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 1/2°. Sea Mile.
Nautical School – Educational establishment in which navigation, seamanship and other subjects connected with shipping are taught.
Nautical Tables – Book containing tabulated data—arithmetical, geometrical, astronomical and geographical—for use in navigation.
Nautical Twilight – The period between the end of civil twilight and the time when the sun’s centre is at 12º below the horizon in the evening, and the period between the time when the sun’s centre is at 12º below the horizon and the beginning of civil twilight in the morning. 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. Related Article: What are the Parts of a Ship and Their Functions.
Naval Brass – Alloy of approximately 60% copper, 39% zinc. See Admiralty brass.
Naval Cadet – Student for officer rank in the 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 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.
Navarea – One of 16 areas into which the International Maritime Organization divides the world’s oceans for dissemination of navigation and meteorological warnings.
Navel Futtock – Ground futtock in midship timber of a wooden ship.
Navel Pipe – Large tube through which cable from deck above locker to cable deck.
Navicert – Certificate of Destination for Specified Cargoes, issued by governments in wartime.
Navicular – Boat-shaped.
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 righthand 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. The science of determining a vessels position and art of planning and plotting a safe passage to another position, with due consideration of the many variables. 2. Canal made for passage of ships, barges and boats. Related Article: Types of Marine Navigation – How Seafarers Find Their Way.
Navigation Charts – A nautical chart is a graphic portrayal of the marine environment, used to lay out courses and navigate by the safest route.
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. The lights that a vessel under way must exhibit between sunset and sunrise so that she may be identified.
Navigational Hazards – Include partially submerged wrecks, containers, floating debris and reefs
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.
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.
Navtex – Telegraphy system for transmission of maritime safety information, navigation and meteorological warnings and urgent information to ships not supported in Australia.
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. A state’s ships of war, their equipment, supply and manning.
NC – International code; Negative Affirmative – signifies distress.
Neap – Applied to the tides of small amplitude occurring about the time of Moon being in quadrature.
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.
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.
Near Coastal – A non specific term. Used in Australian National Domestic Vessel Law to describe a claimed jurisdiction, the Exclusive Economic Zone, within 200nm.
Near Continental – See ‘ Home Trade’.
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 ‘Naris’=ship.
Negative – Opposite of ‘positive’. 2. Annul, or cancel, a signal or order.
Negative pressure respirator (tight fitting) – A respirator in which the air pressure inside the face piece is negative during inhalation with respect to the ambient air pressure outside the respirator.
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.
Negative Surge – Lower than predicted tide.
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 after World War II.
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. Neptune also appears in equatorial crossings. Related Article: My Line Crossing Experience When Passing the Equator.
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.
Nesting – Cargo that stacks.
Net Register Tonnage (NRT) – a ship’s gross tonnage after approved deductions, i.e. non freight earning spaces. A register ton represents 100 cubic feet.
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.
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.
Nettles – Halves of two yams twisted together to make another yarn. 2. Lengths of nettle stuff used for attaching clews to hammocks.
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 notation 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.
Névé – The area of accumulation of snow on the mountain tops that will form the ice of a glacier.
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.
Newel – Vertical timber to take tenons of rails going from breastwork to gangway.
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 1/2 diameters. Made obsolete by modern technology.
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.’
Nitrogen – The most abundant gas in air (78%); colourless and odourless.
‘No Higher’ – Injunction to helmsman, when under sail, not to come closer to the wind.
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.
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.
Nodal Point – Minimum point of tidal range.
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.
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-Bulk Cargo – Cargo such as timber, steel, and vehicles.
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-Passenger Vessel – For the purposes of NSCV Part B it is a vessel that is not— a) a passenger vessel; b) a fishing vessel; or c) a hire and drive vessel. A non-passenger vessel may be certified to carry up to 12 passengers.
Non-toppling Block – Ballasted pulley-block used in lower end of a purchase to ensure that purchase can be rounded up without block capsizing.
Non-vessel-operating common carrier (NVOCC) – a ships agent that conducts business for the ship but does not operate the vessel.
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.
Norman Heads – Shaped extremities of cross piece of wooden bitts. Used for taking turns with ropes.
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.
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.
Norske Veritas (N.V.) – Norwegian classification society.
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 Atlantic Drift – A moderately warm North Atlantic current setting easterly as the tail end of the Gulf Stream.
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 and Asia. Discovered by Nordenskiold in 1878-9.
North Easter – Gale blowing from a NE’ly point.
North Pacific Drift – A moderately warm North Pacific current setting easterly.
North Pole – Northern extremity of Earth’s axis of rotation. North pole of Equator, or Equinoctial.
North Star – Star Polaris α Ursae Minoris.
Northern Rivers – The majestic valleys of the North Coast of New South Wales whose rivers disgorge into the Pacific Ocean, notably, the Hunter, Manning, Hastings, Maclean, Clarence, Richmond and Tweed.
Northern Signs – Signs of Zodiac north of Equinoctial. They are those from Aries to Virgo, both inclusive.
Northing – Distance, or latitude, made good in a N’ly direction.
North-up – A radar mode in which the display is compass stabilised and rotated so that north is top of the screen.
Not Under Command – Said of a vessel’s status when unable to manoeuvre due to exceptional circumstances.
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. Related Article: What is a Notice of Readiness (NOR) in Shipping.
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. Related Article: IALA Buoyage System.
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.
Notos – Southerly wind of ancient Greece. See classical winds.
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.
Numerals – See Code flags numerals.
Nun Buoy – Buoy having the shape of two cones, base to base.
Nunatak – Isolated rocky peak rising from a sheet of inland ice.
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 18 1/2″ of arc, that is 9 1/4 above or below its mean value.