DICTIONARY OF

Deep Sea Leadline 110 Density
Deep Sea Leadline. One-inch cable laid rope, 100 fathoms long, used with deep sea lead.
Marked as hand leadline to 20 fathoms, then every 5 fathoms.
Deep Sea Sounding. Ascertaining sea depths beyond reach of hand lead. Also applied to a
sounding exceeding 100 fathoms.
Deep Tank. Ballast tank extending from 'tween deck to bottom of ship, and from shipside to
shipside. Has centre fore and aft bulkhead, with valve between compartments. May be
utilized for cargo.
Deep Waist. Upper deck in a ship with high forecastle and poop.
Deep Waisted. Said of a ship having a deep waist.
Deface.* To strip a wooden ship of her planking and leave the ribs bare.
Deflector. Instrument invented by Lord Kelvin for measuring directive force of a compass
mounted in a steel or iron ship. Measurements are made with ship's head on four cardinal
points.
Degaussing. Neutralising magnetic effect of steel or iron vessel by encircling her with wires
carrying electric current. Used as protection against magnetic mines.
Degree. Originally, arc of Ecliptic travelled by Sun in one day. Now, angle subtended by
1/360th of circumference of a circle.
Degree of Dependence. Measure of probable error in an observation or assessment.
Dekad. Meteorological name for a period of ten days.
Delambre's Analogies. Formulae for solving spherical triangles in terms of those used for
solving plane triangles.
De Laval Turbine. Uncompounded turbine that is used for driving pumps and dynamos.
Delta. Triangular area of sediment in mouth of a river, so giving river more than one
discharging channel.
Delta Metal. Alloy of copper, zinc and iron. Much used for engineering purposes.
Demi-Culverin. Naval gun of Tudor times. Threw ball of 9-10 Ib.
Demise. Temporary transfer of a vessel to another party under such terms and conditions
that the owner ceases to have any control over her for the period of the charter.
Demurrage. Money paid to shipowner, by charterer, when his ship is detained beyond the
lay days mentioned in charter party.
Deneb Adige. Star Cygni. Usually called 'Deneb'. S.H.A. 50°; Dec. 45°N.
Deneb Aleet. Old name for star Denebola.
Denebola. Star Leonis. S.H.A. 183°; Dec. 15°; Mag. 2-2.
Density. Weight per unit volume, e.g. weight in oz. per cub. ft. Relative Density = Specific
Gravity == Ratio of unit volume of water compared with weight of same volume of fresh
water. 2. Density of sea water is about 1026, but varies between 1000 and 1038 (Port Sudan)
in ports. 3. Density of boiler water is expressed in 1/32nds of increase in weight, 3/32nds
being upper limit tolerated. Due, principally, to sulphate of lime in suspension.