12. Standards for an echo-sounder

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12.1 INTRODUCTION 

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

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

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

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

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

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

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

12.12.1 The equipment shall be provided with an indication of manufacturer, type and/or number.

12.12.2

1. The equipment shall be so constructed that it is readily accessible for maintenance purposes.
2. 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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