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12 STANDARDS FOR AN ECHO-SOUNDER
12.1 INTRODUCTION
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12.1.1 The echo-sounding equipment required by the Navigating
Appliances and Equipment Regulations shall provide reliable
information on the depth of water under a ship to aid navigation.
12.1.2 The equipment shall comply with the following minimum
performance requirements.
12.2 RANGE OF DEPTHS ^
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12.2.1 Under normal propagation conditions the equipment shall be
capable of measuring any clearance under the transducer between 2 metres
and 400 metres.
12.3 RANGE SCALES ^
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12.3.1 The equipment shall provide a minimum of two range scales one
of which, the deep range, shall cover the whole range of depth, and the
other, the shallow range, one tenth thereof.
12.3.2 The scale of display shall not be smaller than 2.5 mm per
metre depth on the shallow range scale and 0.25 mm per metre depth on
the deep range scale.
12.4 METHOD OF PRESENTATION ^
12.4.1 The primary presentation shall be a graphical display which
provides the immediate depth and a visible record of soundings. Other
forms of display may be added but these shall not affect the normal
operation of the main display.
12.4.2 The record shall, on the deep range scale, show at least 15
minutes of soundings.
12.4.3 Either by marks on the recording paper, or by other means,
there shall be a clear indication when the paper remaining is
approximately 10 per cent of the length of the roll.
12.5 ILLUMINATION ^
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12.5.1 Fully adequate illumination shall be provided to enable
identification of controls and facilitate reading of record and scales
at all times. Facilities for dimming shall be provided.
12.6 PULSE REPETITION RATE ^
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12.6.1 The pulse repetition rate shall be not slower than 12 pulses
per minute.
12.7 ACCURACY OF MEASUREMENT ^
12.7.1 Based on a sound speed in water of 1500 metres per second, the
allowable tolerance on the indicated depth shall be:
either
± 1 metre on the shallow range
scale
± 5 metres on the deep range
scale
or
± 5 per cent of the indicated
depth, whichever is the greater
12.8 ROLL AND PITCH ^
12.8.1 The performance of the equipment shall be such that it will
meet the requirements of these standards when the ship is rolling
± 10° and/or pitching ± 5°.
12.9 POWER SUPPLY ^
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12.9.1 The equipment shall be capable of operating in accordance with
the requirements of these standards in the presence of such
variations of the power supply as are normally expected in a vessel.
12.9.2 Means shall be incorporated for the protection of the
equipment from excessive currents and voltages, transients and
accidental reversal of power supply polarity.
12.9.3 If provision is made for operating the equipment from more
than one source of electrical energy, arrangements for rapidly changing
from one source of supply to the other shall be incorporated.
12.10 INTERFERENCE ^
12.10.1 All reasonable and practicable steps shall be taken to
eliminate the causes of, and to suppress, radio interference to other
equipment on board.
12.10.2 Mechanical noise from all units shall be so limited as not to
prejudice the hearing of sounds on which the safety of the ship might
depend.
12.10.3 Each unit of the equipment shall be marked with the minimum
safe distances at which it may be mounted from a standard or a steering
magnetic compass.
12.11 DURABILITY AND RESISTANCE TO EFFECTS OF
CLIMATE ^
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12.11.1 The equipment shall be capable of continuous operation under
the conditions of sea states, vibration, humidity and change of
temperature likely to be experienced in the vessel in which it is
installed.
12.12 MISCELLANEOUS ^
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12.12.1 The equipment shall be provided with an indication of
manufacturer, type and/or number.
12.12.2
- The equipment shall be so constructed that it is readily
accessible for maintenance purposes.
- Information shall be provided to enable competent members of a
ship's staff to operate and maintain the equipment efficiently.
12.13 INTERNATIONAL STANDARD ^
12.13.1 The International Maritime Organization Resolution
"A.224(VII) Performance Standards for Echo-Sounding Equipment"
is the adopted standard.
12.14 EFFECTIVE DATE ^
12.14.1 This Standard comes into force on 1 September 1985.
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