Dictionary of nautical terms

1 THE SEAFARER S WORD A Maritime Dictionary A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Ranger Hope 2007- All rights reserved A A: Code flag; Diver below, keep well clear at slow speed. Aa.: Always afloat. Aaaa.: Always accessible - always afloat. A flag + three numerals: Code flags; Azimuth or bearing. Aback: When a wind hits the front of the sails forcing the vessel astern. Abaft: Toward the stern. Abaft of the beam: Bearings over the beam to the stern, the ships after sections. Abandon: To jettison cargo. Abandon ship: To forsake a vessel in favour of the life rafts, life boats. Abate: Diminish, stop. Able bodied seaman: Certificated and experienced seaman, called an AB. Abeam: On the side of the vessel, amidships or at right angles. Aboard: Within or on the vessel. About, go: To manoeuvre to the opposite sailing tack.

2 Above board: Genuine. Able bodied seaman: Advanced deckhand ranked above ordinary seaman. Abreast: Alongside. Side by side Abrid: A plate reinforcing the top of a drilled hole that accepts a pintle. Abrolhos: A violent wind blowing off the South East Brazilian coast between May and August. : American Bureau of Shipping classification society. Able bodied seaman Absorption: The dissipation of energy in the medium through which the energy passes, which is one cause of radio wave attenuation. Abt.: About Abyss: A deep chasm. Abyssal, abysmal: The greatest depth of the ocean Abyssal gap: A narrow break in a sea floor rise or between two abyssal plains. Abyssal plain: A level region at great depth in the ocean. Access holes: Holes cut in a structure to facilitate entry and exit. : Australian Communication & Media Authority Acid rain: The acidification of rain (largely resulting from atmospheric pollution from burning sulphur rich coal) causing forest die back and reduction of quality of water habitats.

3 Ack.: Acknowledge. A. class: Australian vessel survey class, unlimited offshore. A. class division: Divisions made of steel or equivalent material, suitably stiffened and capable of preventing the passage of smoke and flame up to the end of the first 1 hour of the standard fire test. Accommodation: The living quarters of a vessel. Accommodation ladder: Portable steps providing access from the vessel s entry deck to the waterline. Accumulator: A tank that smooths out pressure variability in a fresh water system. A trap to remove water within a refrigeration system. A-cock-bill A term used to indicate that the anchor is clear of the hawse pipe and suspended above the water, ready for letting go. current: Alternating current is a form of pulsing electricity supplied by alternators. The voltage cycles between positive and negative at a regulated frequency (cycles per second measured in Hertz). Accretion: The process of deposition of material at the bottom of the oceans.

4 Build up of matter over a surface ( ice on rigging, fouling on hulls). Aces: Hooks for the chains. Acorn: Decorative finial for a post. Adams, Joe Australian prolific fast cruising yacht designer tragically murdered in his late years of life in New Guinea. ADCOM: Address commission. Added mass: An effective increase in hull mass caused by the dragged water-flow during motion. Added weight method: A method used to determine a ship s damaged stability by calculating a partial flooding as added weight rather than as lost buoyancy. Adiabatic: Occurring without heat. Adj.: Adjust, adjustment. Admiral: First or highest commander. Admiralty brass: Alloy of approximately 70% copper, 29% zinc. See Naval brass. Adrift: A vessel not attached to the wharf or an anchor. Ad valorum: A term from Latin meaning, "according to value." Advance: The twin vectors of advance (headway/headreach) and transfer are the distance forward and the distance to the left or right that a vessel will make while negotiating a turn (its tactical diameter) or going full astern to avoid a collision (its stopping distance).

5 Advection: The horizontal air movement in the lower atmosphere due to difference in atmospheric pressure (wind). Advection fog: Fog resulting from warm air over relatively colder water. Admiralty: Pertaining to the United Kingdom Naval Command. Admiralty pattern anchor: An older style anchor with crown, twin flukes and a stock perpendicular to its shank. Adze: Shipwrights tool used to face timber (cut surface to shape). Aerial: A length of conducting wire that detects and/or over a band of similarly proportional radio wavelengths. Aero lights: Aids to navigation for aircraft. Aeronautical drift (Da): Drift caused by bailout trajectory or aircraft gliding distance. Aeronautical position: Initial position of a distressed aircraft at the time of re-entry, engine failure, aircrew ejection or bailout. : Aqueous Film Forming Foam Affreightment contract: An agreement by an ocean carrier to provide cargo space on a vessel at a specified time and for a specified price to accommodate an exporter or importer.

6 Afloat: Supported by the surface of the water. Aframax.: The largest dry bulk carriers. Afromosia: African fine straight grained hardwood timber. Dark coloured, easily hand worked and acceptable for marine use. Aft, after: The stern end of a vessel. After body: A vessel s sections aft of amidships. Aft peak: A compartment immediately forward of the stern post usually below the load water line. Aft peak bulkhead: The transverse bulkhead forward of the stern post, being the forward boundary of the after-peak tank that is required to be maintained as watertight. Aft peak tank: The furthest aft tank/compartment (used for fresh water or ballast). After Perpendicular (AP): A line which is perpendicular to the intersection of the after edge of the rudder-post with the designed load water-line. This is the case for both single- and twin-screw merchant ships. For some classes of warships, and for merchant ships having no rudder-post, the after perpendicular is taken as the centre-line of the rudder stock.

7 After rake: The angle beyond vertical of the vessel s overhanging stern structure. Aftermost: Extreme aft end of a vessel. Agba: African straight grained hardwood timber durable for marine use. : Australian geodetic datum. : Australian Geodetic Datum 1966 - the datum used by the Australian Hydrographical Office on Australian Charts which is a different datum used by the GPS. See also WGS84 Age of the moon: The interval since the last new moon. Age of the tide: The interval since the last full/new moon and the next spring tide. Agonic line: A line joining points with no magnetic variation. Aground: Touching the sea bottom. Agulhas Current: A warm Indian Ocean current running southward along the East African Coastline. : All going well. : Australian Height Datum adopted by the National Mapping Council for vertical control for mapping (mean sea level 1966-68). Ahead: Towards the vessel s bow. A-hoy: Used to attract the attention of another vessel.

8 : Australian hold ladders. : Australian Hydrographical Office. A-hull: When a vessel lies perpendicular to the wave fronts. A method of heaving to. : Admiralty information overlay. Air: A mixture of mainly nitrogen, with oxygen and carbon dioxide, constituting the atmosphere with races of inert gasses. Air casing: An upper deck combing surrounding the funnel stack to protect the deck from heat and assist fireroom ventilation. Aircraft carrier: A warship designed to carry planes. Aircraft coordinator ( ): A person who coordinates the involvement of multiple aircraft in SAR operations. Air draught: Height clearance of a vessel. Aircraft glide: Maximum ground distance an aircraft could cover during descent. Air hammer: Compressed air (nail or rattle) gun used to remove surface rust. Air port: A window to provide light and ventilation. Air-purifying respirator: A respirator with an air-purifying filter, cartridge, or canister that removes specific air contaminants by passing ambient air through the air-purifying element.

9 Air tank: A tank that provides additional vessel floatation. A tank of breathable air for underwater scuba divers. Air tight door: A fully sealed door that will exclude air from passing. : Automatic Identification System. : As low as reasonably practical. Alaska current: A warm North Pacific Ocean current running firstly Northward along the Alaskan Coastline then West into the Pacific. Albatross: Large wing spanned ocean wandering seabird, featured in the epic poem the Ancient mariner . Alden, John: American early 20th century classic yacht designer, associated with Herreshoff. A-lee: Away from the direction from where the wind comes from. Alertfa: See alert phase. Alert phase: A situation wherein apprehension exists as to the safety of an aircraft or marine vessel, and of the persons on board. Alerting post: Any facility intended to serve as an intermediary between a person reporting an emergency and a rescue coordination centre or rescue sub-centre.

10 Alignment: To assemble a shaft in line with its bearing to minimise wear and vibration. Alive: A command to be quicker with the task. Aliz : The trade winds. Alkaline: A compound that is chemically opposite to acid. The electrolyte in Ni-Cad batteries of dilute potassium hydroxide. All fours mooring: Anchoring a vessel with two chain cables ahead and two chain cables astern. All hands: All the crew. Allison: The act of striking or collision of a moving vessel against a stationary object (American). : Alarm. All standing: To come to a sudden stop. Aloft: Up the mast or In the rigging. Alongside: Berthed against a wharf or jetty. Allotment note: Traditional payment option for a seaman to dispose of some of his pay to relatives. Articulated loading platform; a partially buoyant tower rising from a universal joint on the sea floor and used for berthing and loading at oil platforms. : Altitude. Altar: A step in a graving dock.