DICTIONARY OF

Segmental Strip 301 Semi-diurnal Tides
Segmental Strip. Rolled steel section with lower side a chord of a circle, the upper side
being an arc appreciably less than a semicircle.
Seiche. Short period oscillation in level of enclosed, or partly enclosed, area of water when
not due to the action of tide-raising forces.
Seine. Long fishing-net, 60 fathoms or more, in the form of a bag. About 8 to 16 ft. deep.
Upper end is buoyed, lower end is weighted.
Seine Boat. Craft for fishing with seine net.
Seine Fishing. Catching fish with a seine net.
Seize. To bind together two ropes, or two parts of the same rope, with small stuff tightly
turned around them.
Seizing. The turns of small stuff with which two parts of rope are seized. Principal forms are
Flat, Round, and Racking seizings.
Seizing Wire. Seven wires, of galvanised iron or mild steel, with six of the wires laid up
around a central wire. Used when seizing wire ropes.
Seizure. Taking of a ship by overpowering force, or by lawful authority.
Selene. Greek word for 'Moon'.
Selenography. The delineation of Moon's face.
Selenology. Branch of astronomy dealing with Moon.
Self-Mousing Hook. Hook having a spring mousing that allows easy hooking on, but
prevents accidental unhooking.
Self-Trimmer. Vessel with large hatches and clear holds that allow coal, grain and similar
cargoes to be teemed into any part of a hold.
Selvagee. Rope made by spunyarn being laid in parallel lengths, and bound together with
marline-hitched spunyarn passed around all parts. Has great flexibility and grip.
Selvagee Strop. Strop made by laying spunyarn in coils and binding it with marline-hitched
spunyarn.
Selvedge. Normal edge of woven material, such as canvas. 2. An alternative form of
'Selvagee'.
Semaphore. Method, or apparatus, for signalling alphabetical letters, numbers or code
signs, by visible movements and changes of position. In nautical signalling, hand flags, or
apparatus having movable arms, is used.
Semi-Diameter. Half diameter of disc of Sun or Moon. As this is the distance of the centre
from the limb it is of great importance when measuring sextant altitudes.
Semi-Diesel Engine. Internal combustion engine in which injected fuel is vaporised by a hot
bulb and compression. Used for working auxiliary machinery, and for propulsion of small
vessels.
Semi-diurnal. Pertaining to, or recurring at, periods of half a day, approximately.
Semi-diurnal Tides. Tides occurring twice in a lunar day.