HANDY BILLY A light tackle for a variety of uses, usually rove with two single blocks.
HATCH Used for many openings aboard ship. In cargo ships more usually refers to the openings leading below the main deck for cargo stowage.
HELM Refers to the actual steering item, be it wheel, tiller, lever or whatever in modern ships. From Old Norse hjalmvoh a rudder handle.
HOLIDAY A gap in ones work such as a missed painted area. Definitely will not please the Boatswain
HOLYSTONE A block of sandstone used for scrubbing wooden decks. I am an expert from my Deck Apprentice days!!
HORSE LATITUDES The latitudes between 30 degrees and 35 degrees North and South. The winds are light, variable or non-existent. There are so many sources given for this one that you get to pick one yourselves.
HOUSE FLAG The special flag of a shipping company, it is flown at the mainmast head or port yardarm in a one masted vessel. In port a small size version can be flown on the jackstaff forward. It is lowered when the last line is let go at departure. However having said that these are fast becoming lost traditions. These days people actually use a signal flag such as the 'Blue Peter' as a House flag, also we see vessels steaming along 'dressed overall' which is most unseamanlike.
IDLER or DAYMAN The crew members not assigned to the Bridge Watch rotation. They worked days and got to sleep throughout the night hours.
ISOGONIC LINES Lines of equal magnetic variation. From Greek isogon meaning equal angle.
JETSAM Anything thrown overboard from a vessel. This is a Legal term in Maritime Law and can ONLY be used for items THROWN overboard.
KILLICK A killick or kedge anchor is the basic 'fisherman's' anchor. It is also the name given a British Royal Navy Able-Bodied Seaman because of the 'Killick' being the insignia of that Rating.
KING SPOKE The spoke which indicates the wheel is upright and has turned the rudder amidships. Usually marked with a brass cap or decorative knotwork such as a turkshead knot.
LAGAN Any article thrown overboard and buoyed for later recovery. This is a Legal term of Maritime Law.
LETTER OF MARQUE A government license authorizing a vessel as an armed private government ship, that is a privateer, under a recognized flag for a certain period of time.
LIVERPOOL MAN When mysterious things happen on "British" ships, for which there is no apparent explanation, we blame him.
LUTINE BELL The ships bell from HMS "Lutine" 1799 mounted at Lloyds of London. It is rung for an important announcement.
So for now