Index to Volume Seven - The People - Dock Family Trees - Glossary . . .

Beam - The measurement (usually in feet) of the widest part of a vessel. [235]

Dead Weight Tonnage - DWT - The actual weight of cargo carried; the difference between loaded and light displacement. [235]

Draught or Draft - the vertical distance in feet from the waterline of a vessel to the lowest point of the keel. [235]

Gross Tonnage - Measurement of total ship capacity ; calculated by measuring the cubic capacity (in cubic feet) of all spaces available for cargo, stores, crew, passengers and engines and dividing by 100. [235]

Isobath - A line on a chart joining all points of equal depth below the surface of the sea. The depths of successive isobaths are all measured from an arbitrary point known as the 'chart datum', which is based on the position of low water at mean Spring tides. [235]

Knot - Speed measurement in standard nautical miles per hour. [235]

Light Displacement - Weight of ship in an unloaded condition (in tons or tonnes). [235]

Load Displacement - Actual weight of ship, cargo, stores, fuel, etc. (in tons or tonnes).

Net Registered Tonnage - NRT - Derived from gross tonnage by deducting the space used for crew accommodation, navigation, engines, fuel, and water ballast ('deducted spaces'). [235]

Standard Nautical Mile - 6080 feet (1852.184 metres) based on the average length of a minute of arc of a meridian, rounded to the nearest 10 feet. [235] (a nautical mile is 800 feet greater than a land mile). [234]

Fathom - unit of depth = 6 feet or 1.8288 metres. [235]

Athwart - Across the width of the vessel perpendicular to the fore and aft centreline of a vessel.