Søgning i bogen
Den bedste måde at søge i bogen er ved at downloade PDF'en og søge i den.
Derved får du fremhævet ordene visuelt direkte på billedet af siden.
Digitaliseret bog
Bogens tekst er maskinlæst, så der kan være en del fejl og mangler.
CHANNEL DEMARCATION. 253
framework tapering from a wide base to a narrow top, or forming some
distinctive geometrical figure, such as a triangle or lozenge. It is essential,
of course, that the beacon should stand out clearly against its background,
and the steps necessary to secure this end will vary according to circum-
stances. One method is to paint the front surface chequerwise in different
colours; another to paint it all one colour, and so on.
Buoys.—The difficulties attending the design of a beacon, evident as
they are in many instances, are not so great as those involved in the case
of a buoy. Steadiness and erectitude are qualities not easily conferred upon
floating structures, while the same precision in regard to locality is impossible
of attainment. Buoys have to be moored to sinkers, and the length of cable
varies from two to three times the maximum depth, which in itself, in tidal
situations, is susceptible of considérable fluctuation, so that a buoy is capable of
mobility within a circle of not inconsiderable diameter. This renders buoys un-
suitable for imparting accurate guidance in regard to alignment. As a general
rille, their utility is limited to indicating the proximity of shallows in their
immediate neighbourhood.
The limiting width of chan-
nels is indicated, in fact, by two
lines of buoys, one along each
boundary. These are termed
starboard and port hånd buoys,
according as they lie to the
right or left of the mariner
who is approaching a port from
seaward. Generally speaking,
the maximum distance be-
tween two consecutive buoys,
on either hand, is a mile or a
mile and a half in wide estu-
aries, and the minimum, per-
haps 300 yards in narrow
channels, exclusive, that is,
of turning-points.
National Systems of
Buoyag’e. —It is interesting
in this connection to compare
the practice of this country
with that of France and Ger-
many. In English practice
spécial stress is laid upon the
shape of the buoy structure;
Figs. 223-225. —National Systems of Buoyage.
more so than in French practice, where colour is every whit as essential as
form. Climatic conditions have something to do with this, for on the English
coast the state of the atmosphère is often unfavourable to the ready per-