Maritime Dictionary – Everything that Starts with Letter “H”

by | Last updated Nov 24, 2023 | Maritime Dictionary | 0 comments

H – Code flag; I have a pilot on board. Sound signal; I have a pilot on board, in restricted visibility. Morse Code; ● ● ● ●

H Bar – Rolled steel section of H shape.

Haar – Local name for a wet sea fog off E. Coast of Scotland.

Hachures – Shading lines on charts to indicate hill slopes.

Hack Watch – Small timekeeper that is set to chronometer time and used on deck for timing astronomical sights.

Hadar – Star β Centauri. S. H. A. 150°; Dec. S60°; Mag. 0.9.

Haddock – An edible marine fish; N. Atlantic.

Hadley’s Quadrant – First English quadrant devised for measuring altitudes. Invented by John Hadley, 1730.

Hague Convention, 1899 – International convention that gave immunity to hospital ships in time of war, and formulated rules for the settlement of international disputes. Hague Rules, 1921. Enunciated certain rules and conditions regarding the carriage of goods by sea; most of these rules being incorporated in the ‘Carriage of Goods by Sea Act, 1924’. Now superseded by the Carriage of Goods by Sea Act, 1971.

Hague Rules – Rules identifying the rights and responsibilities of carriers and owners of cargo, published in 1924 following an international convention that was adopted by many maritime nations.

Hague-visby Rules – Amendments to the Hague Rules published in 1968.

Hail – Precipitation of small pieces of ice, or small balls of packed snow, from cumulonimbus cloud. 2. To call to call out to another vessel or person at a distance by word of mouth.

Hailstone – A single ball of hail.

Hale – Old English form of ‘Haul’.

Half Beam – Beam that is cut to form a hatchway, or to give clearance.

Half Breadth Plan – Plan of a ship from centre line to ship’s side on one side. Shows buttock lines, bow lines and water lines at different draughts.

Half Breadth Staff – Wooden rod marked to show half lengths of ship’s beams. Used for measuring the beams.

Half Cardinal – Name applied to a point of compass halfway between two cardinal points.

Half Crown – Small circular bight in a rope.

Half Deck – Non-continuous deck extending from right forward to about half length of a boat. 2. Covered part of upper deck that is under a poop and contains accommodation for officers, apprentices or crew. 3. Non-continuous deck extending from mainmast to right aft above main deck. 4. Quarters of cadets or apprentices in merchant ships.

Half Decked – Said of a vessel with an upper deck that is not continuous.

Half Ebb – Said of a tide when halfway from high water to low water.

Half Flood – Said of a tide that is halfway from low water to high water.

Half Floor – Frame timber going from keel to the heel of second futtock.

Half Hitch – Made by passing end of rope round its own part and through the bight formed.

Half Mast – The position of a flag when raised halfway up a mast as a sign of mourning.

Half Minute Glass – Sand glass that takes half a minute to run down. Used when timing a ship log and line.

Half Model – A model equivalent to a half-breadth plan that is used in building for the shipwright’s visual guidance, or can be dismantled to provide accurate stencilling templates to facilitate drawing a naval architect’s lines plan.

Half Moon – Phase of moon when at first and third quarters; and half of disc being illuminated.

Half Poop – Low poop about 4 ft. in height.

Half Port – One of two ports, each having a semicircular piece cut away so that they could be closed around a protruding gun.

Half Round Strip – Rolled steel or iron bar having a semicircular section.

Half Tide Rock – Rock that is covered between half flood and half ebb of tide.

Half Tide – Between high and low tide.

Half Timber – Short futtock in those parts of a wooden ship where the bottom is inclined, not flat.

Half-Breadth Plan – Plan that shows the waterlines of one side of a vessel only.

Halibut – A large edible marine flatfish; Atlantic.

Halliards – Ropes by which sails, yards, flags, gaffs, etc., are hoisted.

Halny – A destructive Foehn wind of Southern Poland and Slovakia.

Halo – Circle of light around a luminous body. Particularly applied to such a circle around Sun or Moon when due to refraction caused by ice crystals in atmosphere.

Halshed Chain – Chain sling or strop in which one end of chain is rove through an open link in other end.

Halyards – ‘Halliards.’

Hamal – Star α Arietis. S. H. A. 329°; Dec. N23°; Mag. 2.2.

Hambro Line – Hard laid, three yam small stuff, generally tarred. Used for lashings, seizings and for lacings of sails of small craft.

Hamburg Rules – Rules governing the rights and responsibilities of carrier and cargo interests which may be incorporated into a contract for the carriage of goods by sea either by agreement of the parties or statutorily. These rules were adopted by the United National Convention on the Carriage of Goods by Sea in 1978.

Hammock – Rectangle of special type canvas that contains the naval seaman’s bed.

Hammock Clews – Twelve lengths of nettle stuff, middled and seized in the bight, which are attached to ends of a naval seaman’s hammock so that it can be extended between hooks in beams.

Hammock Cloth – Canvas cover over hammock nettings.

Hammock Hooks – Small hooks screwed into beams of warships for the slinging of hammocks.

Hammock Lashing – Length of small rope with which a naval rating’s hammock is lashed up, with seven turns, when not in use.

Hammock Netting – Small compartment, in a warship, for stowage of hammocks. Formerly, were two rows of netting above bulwarks. Hammocks were stowed between them to form protection against small arms fire and splinters when in action.

Hamsin – A hot and dusty North Africa and Arabian wind in March and May.

Hand – Any one member of a crew.

Hand a Sail – To furl a sail.

Hand Gear – Alternative means by which a machine, usually actuated by power, is actuated by hand.

Hand Lead – Sounding lead, weighing between 10 and 14 Ib., by which sea soundings may be taken by one man in depths not exceeding 20 fathoms (about).

Hand Log – Name sometimes given to common log and log line, to differentiate is from mechanical logs.

Hand Mast – Mast made from one timber, so distinguishing it from a built mast.

Hand Organ – Large holystone fitted with beckets and lines; dragged by two men when cleaning decks.

Hand over Hand – To haul on a rope by putting one hand before the other on the rope, alternately; so keeping a continuous movement instead of a succession of pulls.

Hand Over – To transfer responsibility. Contractually to provide exclusive, unencumbered and vacant possession.

Hand Rope – A grab rope.

Hand Spar –. Straight piece of timber of circular section. Usually a trimmed trunk of a tall tree.

Hand Spike – A bar used as a lever.

Hand Steering Gear – Wheel, and its connections to rudder, when operated entirely by hand.

Hand Taut – Said of a rope when it is hauled as taut as possible by hand. Said of a rope under similar tension even when not hauled taut by hand.

Hand the Log – To haul inboard the logline and rotator so that it does not become entangled.

Hand Tight – ‘Hand taut.’

Handling Ship – Manoeuvring and controlling a vessel by engines, or sails, and helm movements.

Hands – Persons employed to man and work a ship.

Handsail – Small sail managed and controlled by hand.

Handsomely – Slowly and carefully. Keeping a rope or fall well in hand.

Handspike – Short wooden lever, often shod with iron.

Handy Billy – Small and light purchase used for hauling ropes taut and for miscellaneous jobs of a light nature.Has one single and one double block.

Handymax – A dry bulk carrier type of less than 50,000 tonnes and 12 mtr draught, popular for its efficiency and flexibility.

Handysize – A bulk carrier type 40,000-65,000 tonnes. Also a product tanker with size between 25,000 DWT to 41,999 DWT.

Hang – Of a timber, is its downward droop. Vessel is said to hang in the wind if her head comes to it and she does not fall off. To hang a rudder is to suspend it by its pintles and braces.

Hang from the yards – A historic death sentence; to publicly hang from the yard arms.

Hang Judas – Said of a rope when not properly secured; and of any stop, yarn or small line that hangs down freely.

Hanger – A cutlass; so called because it hangs from a belt at waist.

Hanger Bolts – A screw thread on one end and a nut and bolt thread on the other enables machinery easily to be removed or adjusted when using this bolt.

Hanging Bracket – Bracket with its horizontal edge facing downwards, so that attachment is made underneath.

Hanging Compass – Compass having its binnacle overhead and its graduated card facing downwards.

Hanging Knee – Vertical knee or bracket attached to underside of a deck or beam.

Hank for Hank – Said of two sailing vessels when tacking or wearing at the same time. Colloquially used to denote a fair exchange, or equal terms.

Hanks: Attachments for a sail to run along a stay.

Harbour – Port or haven in which a vessel may lie in good safety. Protected waterway suitable for vessel mooring.

Harbour Dues – Charges to vessels entering a harbour, to cover its maintenance.

Harbour Gaskets – Special gaskets for giving a smart and neat appearance to furled sails when in harbour.

Harbour Launch – Small vessel used for conveyance of harbour officials.

Harbour Log – Log book giving details of ship’s work done while in harbour, together with usual log entries in harbour.

Harbour Master – Official having superintendence over a harbour; and who is responsible that harbour regulations are complied with.

Harbour Reach – That part of a river that leads to a harbour.

Harbour Wages – Seaman’s pay before signing on or after signing off. Pay between voyages.

Harbour Watch – Part of duty watch that remain on board to take any action required on a ship in harbour.

Harbourage – Shelter or refuge.

Hard – Boat landing place at which a muddy bottom has been covered with gravel or shingle. 2. Applied to helm orders, means ‘to the fullest extent’.

Hard Chine – If a vessel’s sides meet her bottom at an angle, instead of being rounded, she is said to be hard-chined.

Hard Iron – Iron, or ferrous alloy, that is slow to receive magnetism, but retains it when received.

Hard Laid – Said of a yarn or rope that has been tightly laid up.

Hard Over – Extremes of helm position, usually 35 degrees to either side.

Hard Patch – A plate over placed to cover a hole/damage.

Hard Tack – Nickname for ship’s biscuits.

Hard Up in a Clinch – Seaman’s expression that means being in a critical and difficult position.

Harden – To trim sheets of a sail tighter to create a flatter sail.

Hardwood – A description applied to woods from deciduous broad-leafed trees (Angiosperms). The term has no reference to the actual hardness of the wood.

Harfield’s Compensating Gear – Steering gear in which an eccentric-allymounted pinion actuates a toothed rack shaped to conform to eccentricity of pinion. At small angles of helm the long radius of pinion gives quick movement: at large angles of helm the small radius of pinion gives decreased speed but increased power.

Harmattan – Often dust laden dry winter wind that blows across the Sahara into the Atlantic African coast and Gulf of Guinea.

Harmonic Analysis – The separation of component tides of an undulation and the determination of their individual values and incidence. These values are considered as being due to action of hypothetical tide-raising bodies.

Harmonic Constants – Angular values of hypothetical tide raising bodies at given times and places, together with the amplitudes of waves they generate, and the height of mean sea level, at a place, as related to chart datum.

Harmonic Method of Tidal Prediction – Based on Harmonic Analysis. Assumes that tides are the results of tractive forces of several hypothetical tide-raising bodies, each moving at its proper speed and having an unvarying tractive effort. By tabulating the angular positions of these bodies, at a given epoch, and their tide-raising power, the determination of tidal effect at a place can be derived arithmetically or mechanically.

Harness – Belt and straps fitted with a clip-hook by which the wearer can secure himself to guardrail or rigging in bad weather.

Harness Cask – Wooden tub, with cover, in which salt meat was kept on board in former years. ‘Harness’ has an oblique reference to salt ‘horse’.

Harness Tub – ‘Harness cask.’

Harp Shackle – Shackle in which bow is wider than distance between lugs.

Harpin – A sheer sawn to shape as opposed to being bent to shape around the frames. The harpin may be only a portion of the sheer (usually the forward section) or the complete sheer.

Harpings – The fore parts of the wales of a vessel surrounding the bows and thickened to withstand plunging.

Harpoon – Barbed weapon mounted on a shaft and used in whaling.

Harpoon Depth Finder – Sounding lead carrying a rotator, so measuring vertical distance to bottom in same way as towed log measures horizontal distance. A clamp on rotator is lifted as lead sinks, but drops as lead rises when hauled up — so retaining registration on dial. Now obsolete, but was remarkably accurate.

Harpoon Log – Early form of towed log with registering mechanism in towed unit. This unit was in two parts; one part rotated, the other part carried the registration mechanism.

Harriet Lane –. Name formerly given to tinned mutton. A woman of this name was murdered in 1874.

Harroway Dixon Type – Early type of steamers in which upper parts of framing incline inwards for about one-quarter of breadth, so forming a centre trunk. Outer plating was carried straight up, so making a space in which water ballast could be placed. Vessels of this type were practically self trimming when carrying bulk cargoes.

Hartford Shackle – Special shackle for connecting a mooring wire to ring of a buoy. Wire is shackled to lug at bow of shackle. Pin of shackle has an extended bar at end. When pin is inserted, it is turned through 90° and bar lies alongside shackle; a hinged loop, on side of shackle, drops over it and prevents it turning and unlocking.

Harvest Moon – Full Moon occurring about autumnal equinox. As angle between Moon’s orbit and ecliptic is very small, Moon rises at same time for several days. Can occur only when Moon’s ascending node is in Aries, every 18 1/2 years (about): 1969 was last occurrence. During the Harvest Moon the moon rises as the sun sets and sets as the sun rises.

Has its Cable – A term used to indicate that the anchor is holding

Hatch – Opening in deck that gives access to hold or space below. The cover of a hatchway.

Hatch Bar – Steel or iron bar that secures hatch covers.

Hatch Beam – Removable section of a beam, on which hatch covers are laid. When removed, access to hold is given; when shipped, transverse strength is restored.

Hatch Boat – Half decked fishing boat with hatch through which fish are passed.

Hatch Coaming – Raised wall of steel, or other material, around a hatch. Raises hatch covers above level of deck and carries fittings for securing hatch covers.

Hatch Feeder – Vertical wooden erection between an upper deck hatchway and hatch of a lower hold. Erected when carrying bulk grain. Grain in feeder keeps lower hold full as grain settles down.

Hatch Money – Gratuity formerly given to a shipmaster on right discharge of cargo.

Hatch Rest Section – Specially designed rolled steel section for fitting to coamings of hatches. Has a flat side for attachment to coaming, a shoulder for supporting ends of hatch covers, and a stopping edge to retain covers in position.

Hatchway – Hatch leading to another deck and provided with stairs or a ladder. Sometimes used as meaning ‘Hatch’.

Hatchway Screens – Canvas screens around a hatchway. Formerly, heavy woollen screens around hatchways of warships during action.

Haul – To pull; to drag along. 2. To open seams in planking of ship’s side through excessive strain on rigging. 3. In rope-making, is a bundle of 300 to 400 yarns when ready for tarring.

Haul About – Old method of making a cable laid rope from a long hawser laid rope. One end is turned back, at one-third of length, and laid up around centre part. Other end is then turned back and laid up, around previous parts.

‘Haul of Haul’ – Order given in a sailing vessel before going about Yards are braced as sharply as possible, buntlines are hauled taut, haliards are sweated up. ‘Haul of all’ is more likely.

Haul Round – When said of wind, means ‘to veer’.

Haul the Wind – To come closer to the wind by bracing in the yards.

Hauling Line – Transporting wire, or rope, used for warping or hauling a vessel in a dock or harbour.

Hauling Part – The falls on a tackle.

Hausing In – Former name for ‘Tumble home’.

Haven – Protected waterway suitable for vessels to enter and moor in all sea conditions.

Hawker – Olden sailing vessel. Sloop rigged with long, narrow stern.

Hawse – Angle between a forward extension of a ship’s fore and aft line and a line between stem and anchor. With two anchors down, is angle at stem between lines going to each anchor. Vessel with two anchors down was said to be ‘Riding a hawse’.

Hawse Block – Wooden chock shaped to fit a hawse pipe, and to prevent entry of water when at sea. A hawse plug.

Hawse Bolster – Planking immediately above or below hawse hole of a wooden ship. Name is sometimes applied to ‘Hawse Block’.

Hawse Buckler – An iron covering plate for a hawse pipe.

Hawse Holes – Holes cut in bows of ship, on either side of stem, and through which cable passes from ship to anchors.

Hawse Hook – Breast hook above upper deck.

Hawse Piece – Cant frame next to knight heads in wooden vessel. It forms a solid mass of wood around hawse hole. Name is sometimes given to the wale in which hawse holes are made.

Hawse Pipe – Tube that connects hawse hole with cable deck or forecastle, and through which cable goes from ship to anchor.

Hawse Plug – ‘Hawse Block.’

Hawse Timber – Vertical bow timber in which hawse holes are cut.

Hawse – See hawse pipe.

Hawser – Flexible steel wire rope, or fibre rope, used for hauling, warping or mooring.

Hawser Laid – Said of rope in which yams are spun right handed, laid up into strands left handed, strands laid up right handed.

Hazardous Material Safety Data Sheet – A document detailing the nature, labelling, storage and medical treatment applicable to hazardous materials used or stored in the workplace.

Haze – Atmospheric state in which visibility is reduced to about one mile.

Hazel Rod Fender – Large and long bundle of hazel rods bound with wire and used as fender in docks, alongside ships and hulks, etc.

Hazing – Giving a man a dog’s life by continual work, persistent grumbling and petty tyranny.

Hazmat Code – Signage table to assist fire fighting involving hazardous materials.

Hazmat – Hazardous material.

Head – A marine toilet. Peak of a sail to which the halyard is attached. The toilet. High promontory of land.

Head (of Sail) – In four-sided sails is the upper edge; in triangular sails is the upper corner.

Head Board – Extreme forward bulwark. 2. Small piece of wood inserted in upper corner of flag to ensure that the flag is close up to the truck when hoisted. 3. Stiffener in head of Bermudan sail.

Head Fast – Mooring rope leading forward from fore end of a vessel especially Thames lighters.

Head Knee – Timber fayed sideways to stem of wooden vessel.

Head Ledge – Thwartship coaming of a hatchway.

Head Line – Transporting wire that is run from bow of a vessel to a position ahead when warping. 2. Lacing that attaches head of sail to a gaff or yard.

Head Log – The vertical stem plate connecting the bottom to deck of a square stemmed barge.

Head Netting – Ornamental meshwork bulwarks formerly fitted in many ships.

Head Room – The deck head (roof) height below decks.

Head Rope – Hawser leading forward from bows of a ship to a point outside the ship. May be used for warping or mooring.

Head Sails – All sails that are set forward of foremast.

Head Sea – Waves coming from the direction that a ship is steaming.

Head Sheets – Sheets of head sails. 2. Flooring in fore part of a boat; bow sheets.

Head Timber – Cant timber in fore part of wooden ship, to support gratings.

Head Wind – Wind blowing from a point right ahead of a ship.

Heading – The direction in which a vessel’s bow points at any given time.

Headings – Timbers forming the head of a wooden cask, barrel, etc.

Headreach – See advance.

Head-to-wind – With the bow headed into the wind.

Head-up – A radar mode in which the heading of the vessel is displayed at the top of the radar screen, also called Ships Head Up.

Headway – Forward movement of a ship through the water. The distance forward that a vessel will travel once propulsion has ceased. See advance.

Heart – Inner part of a shroud laid rope. 2. Fibre in strand of flexible wire rope. 3. Triangular deadeye.

Heart Thimble – Grooved metal protector put in eye of a rope. One end semicircular, and tapering to a point.

Heart Yarns – Inside yams of a strand of rope.

Heat Exchanger – A device for using seawater to cool the oil in a marine engine or for cooling a closed circuit water circulation system in the engine.

Heat wave – A period of abnormally hot weather.

Heave – To lift; to haul strongly; to haul in cable; to lift an anchor; to rise up; to throw—as in heaving a lead.

Heave Ahead – To haul a ship or boat ahead on a warp or cable.

Heave and Hold – Order to haul strongly and not to surrender any gain.

Heave and Rally – Injunction to heave forcefully and cheerily.

Heave and Up Pawl – Capstan order to heave enough for a capstan pawl to be lifted. Is also a caution that capstan can walk back.

Heave Astern – Haul a vessel astern by a warp or sternfast

Heave Down – To careen a ship by putting tackles from lower mast heads to a sheer hulk—or other arranged attachments—and then hauling on falls of tackles.

Heave in Sight – To come up over the horizon. Loosely used as meaning coming into sight.

Heave in Stays – To bring a ship to the wind when tacking.

Heave in – To pull in.

Heave Short – Heave in cable until it is at short stay. When a vessel is pulled up to nearly over her anchor.

Heave Taut – To haul in until strain is apparent.

Heave the Lead – To swing and heave the lead so that it falls into the water some distance ahead of the leadsman. To take a sounding with the hand lead-line.

Heave To – To bring ship’s head near to wind and to remain stopped in that position by trimming yards, or working engines, as may be necessary.

Heave, heaving – The movement of a vessel being lifted by a wave or sea.

Heavenly Body – Name that includes star or solar system body.

Heaver – Short wooden lever tapered at both ends.

Heavieside-Kennelly Layer – Ionized layer, in upper atmosphere, that reflects radio waves.

Heaving – Being lifted up by a wave or sea. 2. Hauling heavily on a rope or hawser.

Heaving Alongside – Hauling a vessel alongside by means of ropes or hawsers.

Heaving Line – Small line that is thrown so that one end reaches a position outside ship, and allows connection to be established. A small line thrown first as a messenger for a heavier line later.

Heaving the Log – Throwing a ship log into the water so that speed of ship may be ascertained.

Heaving To. See ‘Heave To’.

Heavy Derrick – Strong derrick specially provided for lifting very heavy weights. Usually has a special heel fitting that takes in corresponding socket fitted on deck, the deck being suitably supported underneath.

Heavy Floe – Piece of floating ice more than three feet thick.

Heavy Weather – Strong wind and rough seas.

Heavy-lift Vessel – A vessel designed for the loading/discharge and transport of heavy cargoes.

Hedgehog – Squid. Limbo. Multi-barrelled mortars firing a pattern of depth charges. Anti-submarine weapons.

Heel – To list as a result of wind pressure, a shift of weight, or turning moment. 2. Junction of stern post and keel. 3. The lower end of a mast that is fitted in a step. 4. Inboard end of a bowsprit or jib boom.

Heel Chain – Chain that prevents heel of jib boom coming inboard.

Heel Knee – Knee connecting keel and stempost.

Heel Over – To list or incline transversely.

Heel Post – Vertical member supporting after end of propeller shaft.

Heel Rope – Rope by which a bowsprit or jib boom is hauled out. 2. Rope that hauls out and secures a studdingsail boom.

Heeling Error – Compass error due to ship not being upright, so causing an unsymmetrical disposal of iron around a compass.

Heeling Experiment – Deliberate listing of a vessel to ascertain her righting moment.

Height – Of a flag, is its vertical dimension. Sometimes used as meaning its breadth. Charted heights are normally taken from the mean high water spring height (check your chart’s datum) to the height of the charted object (the centre of the light with lighthouses).

Height – Elizabethan term for ‘Latitude’.

Height of Tide – Distance that water level is above chart datum when due to tidal effect.

Height of Wave – Vertical distance from trough to crest expressed in feet. May, rarely, exceed 70 feet.

Height Staff – Graduated rod used for measuring heights during the building of a vessel.

Heliacal Rising – The rising of a star or planet during morning twilight.

Heliocentric – Having Sun as a centre.

Heliometer – Instrument for finding solar time and latitude, when appropriately set, at noon.

Heliostat – Instrument used in hydrographic surveying for reflecting Sun’s rays at one observation station to another at distances up 40 miles or so. Used when direct observations and identification of the station are not possible. ‘Heliograph.’

Helm – The steering machinery of a vessel, i.e.; rudder, tiller, wheel, etc. A strong north-easterly Cumbrian wind, (North England).

Helm Indicator – Pointer geared to steering wheel and moving over a graduated arc to indicate amount of helm being used, and angular position of rudder.

Helm Orders – Orders given to a helmsman. The person who steers the boat.

Helm Port – Opening through which a rudder stock passes into a ship.

Helm Port Transom – Wooden stiffener in way of a helm port.

Helm Signal – Sound signal, or visual signal, made to another vessel in sight when altering course under helm.

Helmet – Brass cover over a compass carried in a binnacle. Usually carries the lighting arrangements.

‘Helm’s Alee’ – Report made when under sail and going about. Warns personnel concerned that vessel is coming up to the wind.

Helmsman – Person steering a vessel.

Helmstock – * Old name for a ‘Tiller’.

Hemp – Vegetable fibre, largely from India, from which rope is made.

Hencoop – Enclosed framework in which fowl were formerly carried by sea-going ships.

Hercules – Northern constellation situated south of Draco and Hydra.

Hermaphrodite Brig – Former name for a brigantine. Brig rigged on foremast, schooner rigged on mainmast.

Herring Buss –* Sailing drifter of 10 to 15 tons.

Herring Gull – Sometimes called ‘Silvery Gull’. Common British species.

Hesperus – Name given to planet Venus when an evening star. Greek for ‘Western’.

Hewed – Carved or hacked out of timber rather than sawed out.

High – Alternative name for an anticyclone. 2. A gyro compass is said to be ‘high’ when its indication, in arc, is higher than it should be.

High and Dry – State of a grounded vessel when sea level is below her keel as tide ebbs.

High Court of Admiralty – British court of law in which a judge— assisted by Trinity Masters, who act as assessors and nautical advisers—deals with matters concerning ships and shipping in navigable waters.

High Frequency – Electrical frequency exceeding 15, 000 per second.

High Latitudes – Closer to the Pole; generally considered to be the areas of the Earth more than 55 degrees latitude.

High Pressure System – An atmospheric circulation rotating anti-clockwise in the Southern Hemisphere, associated with light winds and fine weather.

High Seas – Oceans and extra-territorial areas of seas connected with oceans.

High Tide – The high water of any tidal undulation.

High Water – Highest level reached by any particular tidal undulation.

High water Full and Change – The average interval at any place between the moon’s transit and the next following high water on the day of full or new moon.

Highest Astronomical Tide – The average highest predictable tide in average weather and astronomic conditions.

High-Pressure Boiler – Water tube boiler generating steam at pressures between 400 and 650 Ib. per sq. in.

High-Water Mark – Permanent mark that indicates a high-water datum.

Hill & Clarke’s Lowering Apparatus – One of the earliest type of boat releasing gear (1880). Immediately both ends of boat were waterborne the falls became disconnected from boat.

Hip Towing – A towing operation where the tug secures a barge alongside.

Hire and Drive Vessel – A Class 4 vessel for the purposes of NSCV Part B being any vessel that is let for hire or reward, or for any other consideration whatsoever, and that the hirer uses solely for pleasure.

Hire and Payment Clause – Inserted in a time charter to specify amount of money to be paid, and when payment is to be made.

Hitch – Manipulation of end of a rope by which it becomes attached to any object other than another rope’s end.

Hitcher – Thames lighterman’s boathook.

Hoar Frost – Small particles of ice formed by small drops of water being deposited on a surface whose temperature is below that of freezing point.

Hog – Stiff brush used for scrubbing ship’s bottom. 2. To clean bottom of a ship by scraping or scrubbing. 3. Of vessel, to droop at fore and after ends through structural weakness or bad disposition of cargo. Can occur when vessel is excessively supported amidships and not fully supported at ends.

Hog Chain – Iron chain tautly stretched between stem and stern posts. Formerly fitted in some ships to prevent hogging.

Hog Frame – Strong fore and aft frame built to prevent hogging.

Hog Island Ship – American standard cargo ship of the First World War.

Hog Piece – Timber going from forward to after deadwood, in a wooden boat, to increase girder strength and so resist hogging stresses. Is attached to top of keel, and garboard strake is attached to hog piece.

Hogged – A vessel whose keel, as a result of strain, droops at each end.

Hogging – Cleaning ship’s bottom. 2. Drooping of a vessel at fore and after ends and arching at middle part. Also applied to any structural member that droops at ends.

Hogging Strain – Excessive stress that causes a vessel or member to hog.

Hogshead – Cask holding about 52 1/2 gallons, but may vary with different liquids.

Hoist – To lift. 2. Group of flags forming a signal or part of a signal. 3. The perpendicular extent or measurement of a flag. 4. Extent to which a yard or sail can be hoisted.

Hold – Interior space in which cargo is carried in a vessel. One of the divisions into which the interior space is divided.

Hold a Luff – To keep close to the wind when under sail.

Hold Fast – A mechanism used to secure an object.

Hold Pillars – Vertical members extending from floor to beam in a hold. Support deck and help to resist racking stresses.

Hold Stringers – Horizontal strength members going fore and aft alongsides of hold.

Hold Water – To retard or stop fore and aft motion of a rowed boat by putting blades of oars vertically in water, with looms at right angles to fore and aft line, and maintaining them in this position.

Holding Ground – Bottom of sea when its nature is such that an anchor will grip with a reasonable amount of security.

Holding On – Continuing on a course.

Holidays – Days on which it is customary not to work in a given port or country. 2. Spaces carelessly left when painting or cleaning an area.

Hollow & Round – The warpage of a sawn plank of timber where its section is concave on one side and convex on the other.

Hollow Sea – Swell that is not due to a prevailing wind.

Hollow Spar – Spar made out of two pieces, hollowed on the inside to reduce weight.

Holme’s Compass – Magnetic compass designed to control and operate a number of repeaters at remote positions.

Holme’s Light – Calcium phosphide light that ignited on contact with water, giving off both smoke and flame. Attached to lifebuoys to make them more conspicuous when in water. Dangerous in oil spills.

Holophonal – Term applied to a light when its rays are reflected or refracted into a beam.

Holystone – Small piece of soft white sandstone used for cleaning wooden decks by abrasion. To clean with holystones.

Home – In place. Close down. The sheets of a sail are said to be home, when the clews are hauled in tight to the sheet blocks. An anchor comes home when it is weighed and secured.

Home Port – Technically the port of registration of a vessel.

Home Trade – Seaborne trade between British and Irish ports and ports in Europe between Elbe and Brest inclusive. Near Continental and Limited European are terms used at present.

Home Trade Agreement – Contract between master and crew of vessel in the Home Trade. In force for six months from date of opening. Wages were usually on a weekly basis; crew usually found their own provisions; short notice of termination, on either side was fairly general.

Home Trade Limits – Coasts of Great Britain, Northern Ireland, Eire and Channel Islands and coast of Europe from Elbe to Brest, both inclusive. Homeward Bound. Said of a vessel when she is bound for a port in her own country. 2. Colloquial term for any work, particularly sewing of canvas, when it is done hurriedly and carelessly.

Honda Steels – Steel alloys having exceptional magnetic retentivity. They contain cobalt, nickel and aluminium.

Honour Policy – Policy of marine insurance in which the good faith of the insurer is assumed by the underwriter without documentary or other evidence. Policy automatically lapses, against insurer, if good faith is lacking.

Hood – Covering for a hatch or companionway. 2. Cover of a compass mounted in a binnacle.

Hooded, Hooding, Ends – Those ends of planking, of a boat or wood-built vessel, that are fitted into rabbeting on stern and stem posts.

Hook – Transverse connecting piece in fore end of a boat or ship. Name is often given to such fitting in other parts of a vessel.

Hook and Butt – Joint in planking that is made by scarphing or lapping.

Hook Block – Sheaved block that is fitted with a hook for making attachment.

Hook Bolt – Bolt with hooked end for attachment purposes.

Hook Rope – About 10 to 12 fathoms of rope having a hook on one end. Used in working cable, or for general purposes.

Hooker – Colloquial name for a ship. Corrupt form of ‘Hawker’. Historically a small Dutch fluyt, but used to describe roughly built beamy working craft with tumblehome.

Hook’s Law – Generally defined as ‘For elastic strains, strain is proportional to stress.’ Strain equals stress multiplied by a constant that varies with the material under consideration.

Hoops – Wooden rings by which a luff of a fore and aft sail is confined to a mast.

Hope – A small inlet or haven.

Hopper – Usual name for a ‘Hopper barge’; sometimes for a ‘Hopper dredger’.

Hopper Barge – Barge having flap doors in bottom and buoyancy spaces at ends. Receives dredged material from a dredger, and is then towed to a dumping ground.

Hopper Dredger – Dredger having a compartment with flap doors in the bottom. Dredged material is placed in this compartment for subsequent release.

Hopper Tank – A bulk carrier’s lower side ballast tanks, shaped in hopper form.

Horary Circle – ‘Hour Circle.’

Horizon – Line along which sky and surface of Earth appear to meet.

Horizon Glass – Of sextant, is a fixed glass through which horizon is sighted. Half of glass is a reflector in which reflected image of an observed body is sighted and brought down to horizon.

Horizontal – Pertaining to the horizon.

Horizontal Band Width (HBW) –  Radar term, the width of the radar pulse.

Horizontal Danger Angle – Danger angle when measured between two objects in the same horizontal plane.

Horizontal Dilution of Precision  the inaccuracy of a GPS fix due to position lines (satellite derived) at too narrow an angle of intersection. See DOP.

Horizontal Parallax – Value of parallax of a heavenly body when in observer’s horizon. It is then greatest.

Horn Book – Volume giving elementary principles and methods.

Horn Bowsprit – ‘Spike Bowsprit.’

Horn Card – Diagram of cyclonic storm showing navigable and unsafe quadrants. Found in the back pocket of early meteorological books.

Horn Cleat – A deck fitting with two horizontal horn-shaped arms to which lines are made fast.

Horn Timber – Strong timber sloping up and aft from keel of a wooden vessel to form the backbone of the counter. The twin structural timbers at the base of the hull between the top of the sternpost and the transom. The rudder post slots between them.

Horn – A signalling device. A bar or timber used to lash and support a scaffold plank.

Horne – 17th century name for constellation Ursa Major.

Hornpipe – Originally, a Welsh musical instrument. Later, a dance performed to hornpipe music. Now, one of the dances of nautical origin.

Horns – Name sometimes given to jaws of a gaff, or arms of a cleat.

Horse – Beam or bar along which the sheet of a fore and aft sail travels. 2. Foot rope beneath a yard. 3. Ridge rope from knight heads to bowsprit cap, for safety of men working along bowsprit. 4. Breast rope, in chains, for safety of man heaving the lead. 5. Wooden frame on which men sat when woolding mast. 6. Shoal across line of tide and over which a tidal current flows without breaking, but with a slight rise of level.

Horse Iron – Large caulking iron used when horsing.

Horse Knot – Alternative name for ‘Footrope Knot’.

Horse Latitudes – Calm area between trade wind belt and ‘Westerlies’ in Atlantic Ocean. Approximately 30° to 35°N.

Horse Marine – Unhandy seaman.

Horse Packet – Team boat at Yarmouth in early 19th century. Worked by four horses.

Horse Power – Unit of work equivalent to lifting power of 33, 000-foot pounds per minute.

Horsepower – A standard unit of power derived from a carthorse lifting a nominal 550 pound weight up a mine shaft used as an equivalent to specify engines as brake, continuous input, intermittent, output or shaft power capabilities.

Horseshoe Clamp – Iron fastening between fore foot and gripe.

Horseshoe Plate – A plate fitted around the rubber stock for the purpose of preventing water from driving up into the rudder trunk.

Horseshoe Rack – Curved rack, abaft mainmast, carrying ninepin blocks through which running gear of light sails was led to belaying pins.

Horseshoe Splice – Made in end of a single topmast shroud or backstay. End is turned down and a short length of rope is put across bight and spliced into each part. Sometimes used in jib guys.

Horsing – Caulking the seams in ship side planking.

Horsing Iron – Large caulking iron used when horsing.

Horsing Mallet – Heavy wooden mallet used when horsing.

Horsing Up – Final caulking of ship’s side planking.

Hose Coupling – Metal fitting, in end of hose, by which one length of hose is connected to another.

Hose Test – The method by which a seam or weld is tested for watertightness, by applying a jet of water from a hose from one side, and checks made from the other side for any seepage, or passage of water.

Host Men – Fraternity, at Newcastle-upon-Tyne, who were responsible for the carriage of north country coal.

Hot Bulb Engine – Internal combustion engine in which ignition of fuel is assisted by having a hot bulb head in compression-combustion space.

Hot Frames – Frames bent by steaming or boiling.

Hot Plug – A spark plug for low speed operation and heavy duty; the high insulator seat slows the dissipation of heat from the core.

Hot Well – Chamber in which exhaust steam from engines is stored after condensation.

Hounds – Timbers secured on either side of a mast to form rests for crosstrees and upper eyes of rigging. Also, step on mast, made by reducing its diameter, when used for same purpose.

Hounds Band – Iron or steel band secured near head of mast to take upper eyes of shrouds and stays.

Hour – Twenty-fourth part of a day. Interval in which the hour angle of a heavenly body changes 15° in respect to the hour circle of an observer. Arc of 15° of Equinoctial.

Hour Angle – Angle, at elevated pole, between meridian of observer and meridian passing through a heavenly body. Conventionally reckoned westward from observer, but can be expressed as an easterly value.

Hour Circle – Great circle, secondary to Equinoctial, passing through points having the same Right Ascension and, therefore, the same hour circle.

House – To put into a position of increased safety. To lower an upper mast until its head is in line with head of mast below. To run back a gun and secure it.

House Flag – Private and acknowledged flag of a ship’s owner or owners.

Houseboat – A sheltered waters boat designed for occupation.

Housed – Secured or stowed.

Houseline – Soft-laid three-yarn stuff used for general purposes. May be tarred or untarred.

Housing (of Bowsprit) – Inboard part from bed, or wedges, to the heel.

Hove – Heaved.

Hoveller – Person who assists in saving life or property from a vessel wrecked near the coast. Often applied to a small boat that lies in narrow waters ready to wait on a vessel, if required. Possibly a corruption of ‘hoverer’.

Hovercraft (‘Cushioncraft’) – A vessel which can support herself a short distance above the surface of the water or land by exerting a downward pressure of air. Hove To. Lying nearly head to wind and stopped, and maintaining this position by trimming sail or working engines.

Hove-to – A condition the vessel is said to be in when it is heading into the wind and sea but making little or no headway.

Howden-Johnson Boiler – Cylindrical boiler of Scottish type but having external tubes that pass through combustion chamber and connect water below furnaces with upper volume of water. Superheater is mounted above front ends of return tubes. Efficiency is a little less than 0.9.

Howl – To scarph foothooks into the ground timbers of a vessel.

‘How’s Her Head?’  What is the direction of ship’s head at this moment?’

Hoy – Small, one-masted sailing vessel used for short voyages or for carrying passengers or goods to or from ships.

Huffler – Man employed to man handle sailing barge into upper reaches of a creek in Thames estuary.

Hug. To keep close to.

Hulk – Hull of a vessel not fit for sea service. Sailing vessel without masts. 2. In 13th to 15th centuries a vessel larger than the earlier cog. Hulc/hourque.

Hull – Body of a ship, and excluding interior fittings. The main structure of a vessel.

Hull Down – Said of a distant ship when her hull is below horizon and her masts and upper works are visible.

Hull Speed – The maximum speed to which a hull can be driven before it must climb out of the wave of displaced water that its movement has created. To move beyond that speed requires exceptional power or fine lines suited to planing. Hull speed is limited to a factor of approximately 0.8 to 1.5 times the square root of the waterline length in feet.

Hulling – Floating, but at mercy of wind and sea. 2. A hull. 3. Piercing the hull with a projectile. 4. Taking in sail during a calm.

Humber Keel – Flat-sided, round-ended, flat-bottomed vessel used in Humber and other Yorkshire waterways. Has one mast amidships, square mainsail and a topsail. Mainsail can be single or double reefed to yard.

Humboldt (Peru) Current – A cool South Pacific current.

Humidity – The amount of water vapour in the air.

Humidity-Mixing Ratio – Relative weights of water and vapour forming damp air. Expressed as number of grams of water-vapour combined with a kilogram of dry air.

Hummock – Small hill.

Humpbacked Whale – Rather short whale having nippers of a length up to onethird length of body. Occasionally seen in British waters.

Hunter’s Moon – Full moon following Harvest Moon. Characteristics are somewhat similar to those of Harvest Moon, but less marked.

Hunting Gear – Mechanism by which a differential motion is produced so that the final movement of some part is the result of two movements having opposite effects. Used in steering engine mechanisms to stop the engine when rudder has been turned through an angle that corresponds with angle indicated at wheel.

Hunting Tooth – Tooth, in a wheel actuated by a pinion, that is in excess of a multiple of the number of teeth in the pinion. It ensures that any tooth in pinion will not mesh continually into same teeth of wheel.

Hurricane – Violent cyclonic storm, especially around Cape Verde Islands, Atlantic seaboard of U. S. A., West Indies and Gulf of Mexico. Any wind of Force 12 on the Beaufort Scale.

Hurricane Deck – A superstructure deck. Formerly, a deck reserved for use of officer of watch, or commander.

Hurricane Lamp – More or less stormproof oil lantern used for general purposes of illumination about decks and open spaces.

Husband – Owner’s representative who formerly went with ship to take charge of stores, arrange for repairs and transact ship’s business. In Plantagenet times he was the sailing master.

Hyades – Cluster of five (formerly seven) stars in the head of Taurus.

Hydra – ‘Water Snake.’ Long constellation extending south of Cancer, Leo and Virgo. Principal star is Alphard—Cor Hydrae.

Hydraulic Jack – Machine by which heavy weights may be lifted by pumping small quantities of water underneath a ram.

Hydrochlorofluorocarbons (HCFC) – typically ozone depleting compounds.

Hydrofoil – A fast vessel which, when at speed, lifts her hull clear of the surface of the water, supporting herself upon foils, or wings, which project beneath her bottom.

Hydrogaph Rudder – Rudder so mounted that a gap, between its leading edge and sternpost, is formed when rudder is angled. This allows water to flow from pressure side of rudder to suction side when angled.

Hydrograph – A recording hygrometer.

Hydrographer – One who surveys oceans, seas and inland waters for the purpose of navigation and commerce; and who produces charts and sailing directions to impart the information obtained.

Hydrographer of the Navy – A senior officer—usually a flag officer— of the Royal Navy who is responsible for British hydrographic work. First to be appointed was Alexander Dalrymple, 1795. First R. N. officer was Captain Thomas Hurd, 1808.

Hydrographic Department – Branch of Admiralty, founded in 1795, to ‘select and compile such information as might appear to be requisite for the purpose of improving navigation’. Is responsible for all hydrographic work and for the publication of requisite information regarding surveys, tidal data, chart preparation, etc.

Hydrographic Office – Branch of U. S. Navy corresponding to British Hydrographic Department.

Hydrographical Abbreviations – Standard abbreviations used in charts and hydrographic notices.

Hydrography – The science and practice of surveying oceans and seas, the charting of coasts, the collection of information relating to navigation, the production of charts and sailing directions, the investigation of tides, and the placing of the ascertained facts at the disposal of navigators and others concerned.

Hydrography – The science of measuring the marine world to produce information for the safe passage of navigators.

Hydrology – The study of water.

Hydrometeorology – The study of the atmospheric processes associated with water.

Hydrometer – Instrument for measuring the density of liquids. Usually consists of a ballasted float carrying a scale that indicates density as related to fresh water. This zero is 1000; the density of sea water is about 1026, but varies, in different ports and areas, between 1000 and about 1040.

Hydrophone – Instrument for collecting sound transmitted by water.

Hydroplane – A hull designed to progressively rise over the surface of the water and skim the surface. See hydrofoil.

Hydrostatic – Pertaining to the principles of equilibrium of fluids. See Hydrostatic Release Unit.

Hydrostatic Test – A pressure test using a static head of water applied to components.

Hygrometer – Dry and wet bulb thermometers mounted alongside each other so that depression of wet bulb can be ascertained and humidity of atmosphere deduced. Instrument for measuring humidity.

Hygroscopic – Capable of abstracting moisture from the atmosphere.

Hypalon – Superior grade of rubberised fabric used for inflatable craft –see PVC.

Hyperacme Block – Heavy lift purchase consisting of upper sheave having a toothed disc, into which a worm engages, and a sprocket wheel of smaller diameter. Length of chain is secured to framework, passes through a single shave hook block and then into sprockets on upper shave. Worm is actuated by endless chain going over sprocket wheel secured at end of worm shaft.

Hyperbaric Lifeboat – Totally enclosed fire resisting lifeboat with compressed air supply to maintain sufficient pressure to ensure that smoke does not enter the boat. See Solas Chapter III 45 & 46.

Hyperbola – A curve, any point upon which has the same difference of distances between two fixed points, called loci: e. g. point X, 10 units from one locus and 8 from the other: difference 2; point Y, 13 from one locus and 11 from the other: difference 2.

Hyperbolic Navigation – Finding a Position Line or Position Lines corresponding to a hyperbola or hyperbolae associated with a chain of two or more radio stations.

Hyperthermia – Dangerous rise in body heat.

Hypothermia – Abnormal lowering of internal body temperature (heat loss) from exposure to cold air, wind or water.

Hysteresis – The lagging behind of a certain amount of magnetism when an object has been temporarily magnetised and the magnetising agent has been withdrawn.



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