Glossary of Technical Terms used in Connection with
the Docks and Riverside Sites
Accumulator: an apparatus for collecting and storing
water pressure or electricity.
Altar: a step or ledge in the wall of a dry dock, used to
hold the wooden supports which steady the vessels when
the dock is empty.
Apron: a platform or hard surface at the bottom of a
dock entrance to intercept the fall of water and prevent
the erosion of the bottom.
Bascule bridge: a type of drawbridge, hinged, with a
counterweight, which raises to allow ships to pass beneath
Caisson: a pontoon or floating gate used to close a dry
dock; also a watertight chamber or other structure used,
often in combination with compressed air, to keep water
or soft earth out of a site during construction work; also
an apparatus for lifting a vessel out of the water for
repairs or inspection.
Campshedding: a retaining wall of timber piles to protect
or hold back the river bank.
Chevaux de frise: a line of spikes or nails fixed along the
top of a wall or railing.
Coal-meter: one who measures or weighs coal.
Coal-whipper: one who raises coal out of a ship's hold
by means of a pulley.
Counterfort: a strengthening pier or buttress in a retaining
Derrick: a contrivance or machine for hoisting and
moving heavy weights; a simple crane (apparently the
surname of a celebrated seventeenth-century hangman at
Drawdock: an inlet in a river where boats can unload
cargo or lie at low water.
Dolphin: a post, buoy or platform for mooring a vessel,
sometimes situated at the entrance to a narrow harbour
or dock as a guide to shipping.
Fairleads: see Snatch-heads
Garner: a store or granary.
Graving dock: a dry dock, originally a dock where ships'
bottoms were cleaned and smeared with tar (a process
known as graving, possibly derived from graves or greaves,
the dregs of tallow).
Greenheart: a South American hardwood.
Gridiron: a wooden framework on to which a ship
could be floated at flood tide, allowing for repairs and
maintenance when the water receded.
Heel post: the corner post of a lock gate, to which the
gate is fastened
Invert: an inverted arch, as at the bottom of a canal or
Jigger: a loose chain used as a light warehouse crane.
Loophole: one of the vertical series of doors in a warehouse, through which goods are delivered by crane.
Level-luffing crane: a crane which, during luffing (the
raising or lowering of the jib), maintains the load at a
constant height, moving it horizontally.
Luffing crane: a crane with the jib hinged at the foot to
allow the angle of operation to be altered.
Mould loft: a room where the drawings were turned into
full-size templates or 'moulds' for the shipwrights to
Paddle: a sliding panel in a lock gate or sluice gate which
regulates the flow or level of water.
Penstock: a sluice gate for controlling water flow, which
opens by lifting upwards.
Pug mill: a machine for mixing and tempering clay.
Scoop wheel: a wheel driven by wind or steam for lifting
Scupper: an opening in the side or floor of a building to
allow excess water to drain off.
Sheerlegs (also sheer legs or shearlegs): a device for lifting
heavy loads, consisting of two poles lashed together at
their upper ends, from which a pulley is suspended.
Snatch-heads or fairleads: fixtures used to alter the
direction of a hauling rope or cable.
Toe: the part of the base of a dam or retaining wall on
the free side, away from the retained material.
Trunnion: one of a pair of side projections on which an
object (such as a cannon) is pivoted to move in a vertical
Turning bridge: a bridge turning horizontally on a pivot;
Wales or whales: horizontal supports (usually of timber,
sometimes of iron) used to bind together piles driven in