ABAFT :
Toward the stern of a ship;
back; behind; back of; further aft than.
ABEAM :
At right angles to the keel.
ABOARD :
On or in a ship.
ABREAST :
Side by side; over against;
opposite to.
ACCOMMODATION LADDER :
Stairs slung at the gangway, leading down the vessel's side to a point near the water, for ship access from small boats.
AFT :
Near the stern; toward the stern.
AFTER BODY :
That portion of a ship's
body aft of the midship section.
AFTER FRAMES :
Frames aft of
amidships, or frames near the stern of
the ship.
AFTER PEAK :
The aftermost tank or
compartment forward of the stern post.
AFTER PERPENDICULAR :
A line
perpendicular to the base line
intersecting the after edge of the stern
post at the designed water line. On
submarines or ships having a similar
stern, it is a vertical line passing
through the point where the designed
water line intersects the stern of the
ship.
AIR CASING :
A ring-shaped plate
coaming surrounding the stack and
fitted at the deck just below the
umbrella, to protect the deck from heat
and to help ventilate the fireroom.
AIRCRAFT CARRIER :
A vessel designed
to carry aircraft and fitted with a flying
deck from which aircraft are launched
and on which they land. A floating
flying field which usually operates as a
unit of a fleet.
AIR PORT :
An opening in the side or
deck house of a vessel, usually round
in shape and fitted with a hinged frame
in which a thick glass is secured. The
purpose of the air port is to provide
light and ventilation to and vision from
the interior of the ship. In some
instances the air port is also provided
with an additional solid metal hinged
cover for purposes of protection of the
interior should the glass be damaged or
to prevent light from showing from
within.
ALOFT :
In the top or upper rigging; on
the yards; above the decks.
AMIDSHIPS :
In the vicinity of the
middle portion of a vessel as
distinguished from her ends. The term
is used to convey the idea of general
locality but not that of definite extent.
ANCHOR :
A heavy iron or steel
implement attached to a vessel by
means of a rope or chain cable for
holding it at rest in the water. When an
anchor is lowered to the bottom, the
drag on the cable causes one or more
of the prongs, called flukes, to sink into
or engage the ground which provides
holding power.
* Ring (Shackle) - Device used to
attach the anchor chain to the shank of
the anchor. The ring is secured to the
top of the shank with a riveted pin.
* Shank - The long center part of the
anchor running between the ring and
the crown.
* Crown - The lower section of the
anchor to which the shank is secured.
The shank is fitted to the crown with
(on some anchors) a pivot or ball-and-
socket joint that allows a movement
from 30o to 45o either way.
* Stock - a crossmember, spar, or rod,
that rolls the anchor into an attitude
that enables the flukes to dig into the
sea bed. Most newer anchors are
stockless.
* Arms - The parts that extend from
each side of the crown.
* Throat - The inner part of an arm
where it joins the shank.
* Fluke or Palm - The broad shield part
of the anchor that extends upward from
the arms.
* Blade - That part of the arm extending
outward below the fluke.
* Bill or Pea - Tip of the palm or fluke.
* Cup - on a Mushroom Anchor, the
round ground-holding portion
corresponding to the fluke of other
designs
ANCHOR'S ACOCKBILL:
when the
anchor is suspended perpendicularly
from the cathead, ready to be let go.
ANCHOR'S APEAK -
when the anchor
cable is drawn in so tight as to bring
the ship directly over it.
ANCHOR'S ATRIP -
when the anchor is
lifted out of the ground. Same as
"Anchor's Aweigh".
ANCHOR'S AWASH -
when the anchor
is hove up to the surface of the water.
ANCHOR'S AWEIGH -
said of an
anchor, during the weighing (raising) of
the anchor, when just clear of the
bottom
ANCHOR BALL -
a round black shape
hoisted in the forepart of a vessel to
show that it is at anchor
ANCHOR BELL -
a warning bell
mounted on the foredeck and rung
while at anchor in foggy conditions
ANCHOR BEND -
a very secure knot
used to tie rode to anchor
ANCHOR DETAIL -
a group of men who
handle ground tackle when the ship is
anchoring or getting underway
ANCHOR, BOWER :
The large anchors
carried in the bow of a vessel. Three
are usually carried, two (the main
bowers) in the hawse pipes, or on bill
boards, and a third (spare) lashed on
deck or elsewhere about the vessel for
use in the event either of the main
bowers is lost. The weight varies with
the size and service of the ship.
ANCHOR BRAKE:
The anchor brake, as
the name implies, is a friction brake
designed to stop, or hold, the shaft
thereby preventing the anchor from
dropping.
ANCHOR BUOY:
A small buoy
occasionally used to mark the position
of the anchor when on the bottom;
usually painted green (starboard) or red
(port), and secured to the crown of the
anchor by a buoy rope.
ANCHOR CHAIN -
chain attached to the
anchor. The chain acts partially as a
weight to keep the anchor lying next to
the ground so that it can hold better.
ANCHOR CHOCKS -
deck fittings for
storing the anchor
ANCHOR ICE -
ice of any kind that is
aground in the sea
ANCHOR, KEDGE :
A small anchor used
for warping or kedging. It is usually
planted from a small boat, the vessel
being hauled up toward it. The weight
varies, being usually from 900 to 1,200
pounds.
ANCHOR LIGHT -
a white light
displayed by a boat or ship at anchor.
Two such lights are displayed by a ship
over 150 feet (46 m) in length, Also
called a riding light.
ANCHOR POCKET -
a recess in the bow
for storing an anchor; also called a
billboard
ANCHOR, SEA :
This is not a true
anchor, as it does not sink to the
bottom. It is a conical-shaped canvas
bag required by the Steamboat
Inspection Service to be carried in each
lifeboat. When placed overboard it
serves a double purpose in keeping the
boat head-on into the sea and in
spreading a vegetable or animal oil
from a container placed inside the bag.
It is sometimes called an oil spreader.
ANCHOR, STREAM :
An anchor
weighing from about one-fourth to one-
third the weight of the main bowers and
used when mooring in a narrow channel
or harbor to prevent the vessel's stern
from swinging with the current or the
tide.
ANCHOR WATCH -
making sure the
anchor is holding and that the boat is
not drifting. Important during rough
weather and at night. Most marine GPS
units have an Anchor Watch alarm
capability.
ANEMOMETER -
an instrument for
measuring the speed of the wind
ANEROID BAROMETER -
an instrument
that determines atmospheric pressure
by the effect of such pressure on a thin-
metal cylinder from which the air has
been partly exhausted
ANGLE OF ATTACK -
the angle between
the chord of a sail and the relative wind
or between the chord of a hydrofoil
such as a keel or rudder and a vector
line representing the true path through
the water, taking the amount of sideslip
or leeway into account. The term
applies to a sail only when the relative
wind is forward of the beam.
ANGLE :
Same as angle bar.
ANGLE BAR :
A bar of angle-shaped
section used as a stiffener and for
attachment of one plate or shape to
another.
ANGLE BULB :
A structural shape
having a bulb on one flange of the
angle, used as a frame, beam, or
stiffener.
ANGLE COLLAR :
A collar or band made
of one or more pieces of angle bar and
fitted tightly around a pipe, trunk, frame,
longitudinal, or stiffener intersecting or
projecting through a bulkhead or deck
for the purposes of making a watertight
or oil tight joint. See Stapling.
ANGLE OF SAIL -
the angle between the
vessel's compass course and the true
wind
ANTI-FOULING -
a type of paint that is
resistant to barnacles, moss, seaweed,
marine grass and various other plant
and animal life that would want to
adhere to a vessel's hull and slow or
damage the hull. There are four basic
types: ablative, sloughing, modified
epoxy, and vinyl, all of which usually
contain copper biocide.
ANTITRADES -
the prevailing westerly
winds of the middle latitudes. The
winds to the north of the trade winds
which blow in the opposite direction
Since the early square rigged ships
could not sail to weather, they had to
cross to the New World on the trades or
tradewinds, and return by a more
Northerly route in the antitrades
ANNEAL :
To heat a metal and to cool it
in such a fashion as to toughen and
soften it. Brass or copper is annealed
by heating to a cherry red and dipping
suddenly into water while hot. Iron or
steel is slowly cooled from the heated
condition to anneal.
Anti-trip Chine - a flared out aft section
of the side and bottom of a boat. The
purpose is to prevent the hard chine of
the boat catching a wake or small wave
on a sharp turn.
Apeak or Apeek - 1. more or less
vertical. (You may hold your oars
apeak, raise your gaff apeak or be
apeak your anchor. 2. (of a dropped
anchor) as nearly vertical as possible
without being free of the bottom. 3. (of
an anchored vessel) having the anchor
cable as nearly vertical as possible
without freeing the anchor. Sometimes
it is necessary to do this in order to let
wave action break the anchor loose.
Aport - on or toward the port side of a
ship; as in: “Come ten degrees aport.”
Apparent Horizon - the plane where the
earth or water and sky seem to meet
Apparent Time - the time of day
indicated by the hour angle of the sun;
i.e. apparent noon locally would be the
moment when the sun is at its zenith. A
properly mounted sundial indicates
apparent time. The concept is employed
when making navigation calculations. A
sun sight at noon and a simple
calculation can produce a very accurate
line of longitude
Apparent Wind - the direction and
velocity of the wind relative to the
speed and direction of the boat which is
derived from the True Wind and Wind of
Motion
APPENDAGES :
Relatively small
portions of a vessel extending beyond
its main outline as shown by transverse
and water plane sections, including
such items as shafting, struts,
bossings, docking and bilge keels,
propellers, rudder, and any other
feature, extraneous to the hull and
generally immersed.
Apron - a timber fitted abaft the stem to
re-enforce the stem and give a
sufficient surface on which to land the
hood ends of the planks
ARBOR :
The principal axis member, or
spindle, of a machine by which a
motion of revolution is transmitted.
ARCHING :
Sometimes used in lieu of
"hogging".
Arc of Visibility - the portion of the
horizon over which a lighted aid to
navigation is visible from seaward
Arctic Ocean - the northern polar ocean
north of Alaska, Canada, Russia,
Greenland, etc.
AREA OF SECTIONS :
The area of any
cross section of the immersed portion
of a vessel, the cross section being
taken at right angles to the fore and aft
centerline of the vessel.
Argosy - an extremely large ship or
fleet of ships, especially merchant
ships. (archaic)
Arm - 1. a branching waterway from a
harbor or bay 2. The crosspiece of an
anchor from the crown to flukes
Armada - a fleet of warships
Arming - tallow or other sticky
substance placed in the recess at the
lower end of a sounding lead for
obtaining a sample of the bottom
Ash Can - World War II slang for a depth
charge
Ashore - On shore or beach; as in,
"Send someone ashore to find fresh
water."
Aspect Ratio - the relationship between
the height of a sail and its breadth. i.e.
A sail with a height of 30' and a breadth
of 20' has an aspect ratio of 3:2. A tall
and narrow sail is said to have a high
aspect ratio.
Astarboard - in or toward the direction
of the right side of the ship when facing
forward, as in: "Pass the marker, then
turn hard astarboard."
ASTERN :
Signifying position, in the rear
of or abaft the stern; as regards motion,
the opposite of going ahead;
backwards.
Astrolabe - a primitive portable
insturment used to measure celestial
angles. The predecessor to the sextant.
Astronavigation - Celestial navigation.
Determining your positon by sightings
of celestial bodies.
Astronomical Almanac - a catalogue of
tables showing the location of various
celestial bodies at specific moments in
time throughout the year; consulted by
the navigator in preparation for taking
sights of celestial bodies. Such tables
were known as "The Ephemeris" since
the 18th C. until 1981 when it was
jointly published by the US and Britian.
Atmospherics - interference in reception
of radio communications caused by
natural phenomena such as lightning or
sunspots; as in: “Atmospherics are so
bad I can’t understand his
transmission.”
Atoll - a roughly circular island created
by and of coral, most common in the
South Pacific, surrounding a lagoon
Athwart or Athwartships - at right
angles to the fore and aft or centerline
of a ship. Across, from side to side,
transverse, across the line of a vessel's
course.
Aurora - a luminous phenomena
caused by electrical discharge in the
upper atmosphere
Aurora Australis - an aurora in the
southern hemisphere
Aurora Borealis - an aurora in the
northern hemisphere
Auto Pilot - an electrical automated
steering mechanism used to steer a
preset course based on the apparent
wind. These are expensive and very
susceptible to breakdown, but most
handy when there is not enough wind to
operate a windvane. Compare to
Windvane on this page
Auxiliary - 1. an engine used when
there is no wind or for assistance in
approaching a dock, etc. 2. a tender
carried on deck
Avast! - given as a command to stop,
cease, and desist the action currently
being carried out (archaic term used in
movies)
Awash - setting so low in the water that
the water is constantly washing across
the top surface
Aweigh - the position of the anchor just
as it clears the bottom when raising it
Awl - a pointed wooden or steel tool
used to poke holes in leather and for
unlaying the ply of a rope for splicing
Compare to Marlinespike and Fid
Azimuth - the horizontal direction of a
celestial point from a terrestrial point
Azimuth Circle - a circular sighting
device that fits around the ship's
compass for taking bearings of
terrestrial or celestial bodies
ATHWART :
ATHWARTSHIP :
Reaching across a
vessel, from side to side.
AUXILIARIES :
Various winches,
pumps, motors, engines, etc., required
on a ship, as distinguished from main
propulsive machinery (boilers and
engines on a steam installation).
AWNING :
A roof like canopy of canvas
suspended above a vessel's decks,
bridges, etc., for protection against sun
and weather.
