FOG SIGNALLING APPABATU8
In Fog.—Four strokes (4) on a deep toned bell.
Wreck Buoy.—Green spherical giving one green flash (1) every 5
or 6 seconds if lighted. Chart abbreviation, Sph. G-n. Fl. (1) ev. 5 sec.
Wreck marking vessels should be given a wide berth when passing
them?
INFORMATION RE FOG SIGNALS.
The following information in regard to fog signals is promulgated
for the guidance of mariners:
1. Fog signals are heard at greatly varying distances.
2. Under certain conditions of atmosphere, when an air fog signal
is a combination of high and low tones one of the notes may
be inaudible.
3. There are occasionally areas around a fog signal in which it is
wholly inaudible.
4. A fog may exist a short distance from a station and not be
observable from it, so that the signal may not be sounded.
5. Some fog signals cannot be started at a moment's notice after
signs of fog have been observed.
Mariners are therefore warned that fog signals cannot be implicitly
relied upon and that the practice of sounding should never be neglected.
Particular attention should be" given to placing "Look-out men5' in
positions in which the noises in the ship are least likely to interfere
with the hearing of the sound of an air fog signal; as experience shows
that, though such a signal may not be heard from the deck or bridge
when the engines are moving, it may be heard when the ship is stopped,
or from a quiet position. It may sometimes be heard from aloft though
not on deck.
There are three means adopted for signalling in fog:—
(a) By air sound signals comprising (1) Diaphone, (2) Siren,
(3) Reed, (4) Nautophone, (5) Gun, (6) Explosive, (7) Bell
or Gong, and (8) Whistle;
(b) By submarine sound signals produced either by (9) an
Oscillator or (10) Bell; and
(c) By Wireless Telegraphy.
I. Air Fog Signals.
The Diaphone (1), Siren (2), and Reed (3) are all three compressed
air instruments fitted with horns for distributing the sound.
The Diaphone emits a powerful low-tone note terminating witfc a