Jack Cloughts: Ground paddles on the Leeds & Liverpool canal worked by a long lever which caused them to slide sideways rather than the normal mechanism which pulls them up.
Jack Nastyface: Nickname for an unpopular seaman. Originally, nom de plume of a seaman who wrote a pamphlet about conditions in Royal Navy in early years of 19th century.
Jackstaff: The term given to the flag pole on the bows of a H.M ship that carries the Union flag. The Union flag then becomes a Union Jack.
Jackstay Rigged line to which safety harnesses may be clipped
Jackyard A yard or pole extending the head or foot of the topsail beyond the topmast or gaff of a gaff-rigged boat
JACOBS LADDER A rope ladder, lowered from the deck, as when pilots or passengers come aboard.
JACOBS LADDER A rope ladder, lowered from the deck, as when pilots or passengers come aboard.
Jam Cleat A cleat designed to allow a line to be made fast quickly by jamming it down
Jerque: Search of a vessel, by Customs authorities, for unentered goods.
Jetsam Anything thrown overboard
Jetsam Goods thrown or lost.
Jettison The act of intentionally throwing cargo overboard e.g. with the objective of lightening a vessel, which has run aground, such for the common good of all interests: vessel, crew and remaining cargo
JETTY A structure, usually masonry, projecting out from the shore; a jetty may protect a harbor entrance.
jib A triangular sail bent to a foremast stay.
Jib 1. Projecting arm of a crane.2. Attachment connected to the top of a crane boom.
Jib Boom Spar attached to bowsprit, pointing forwards.
jib netting A rope net to catch the jib when it is lowered.
Jib Sails Sails carried on stays between bowsprit/jib and foremast.
Jib Sheet The lines that lead from the clew of the jib to the cockpit and are used to control the jib.
jib stay The stay that the jib is hoisted on. Usually the headstay.
jib topsail A small jib set high on the headstay of a double headsail rig.
Jibe To change direction when sailing in such a manner that the stern of the boat passes through the eye of the wind and the boom changes sides. Careful control of the boom and mainsail are required when jibing to prevent a violent motion of the boom when it switches sides.
Jibstay Another word for headstay on which jibs are hoisted
Jimmy Bungs: Nickname for a ship's cooper.
Job That work which is undertaken to meet a customer or production order and, for production control purposes, has a unique identification.
Joint Venture A joint activity of two or more companies usually performed under a common name.
Jolly Boat: General purpose boat of a ship.
Journey A voyage from one place, port or country to another one, in case of a round trip, to the same one.
Junction The place where one waterway joins another.
Juridical decisions used for explanation and meaning of law.
Jurisprudence Juridical decisions used for explanation and meaning of law.
Jury Rig A temporary replacement of any part of the boat's rigging setup after it has broken
Just In Time The movement of material/goods at the necessary place at the necessary time.