DICTIONARY OF

Nacodah 231 ___ ____Nauropometer
N
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.