These Performance Standards for Echo Sounding Equipment are applicable for ship speeds from 0 up to 30 knots. The purpose of echo sounding equipment is to provide reliable information on the depth of water under a ship to aid navigation in particular in shallow water. Echo sounding equipment should comply with the following performance requirements. Sound speed in water for the purpose of this standard is set at 1500 m/s:
SOLAS Chapter V, Regulation 19 states the requirement of Echo Sounding. As per Regulation V/19 it states "All ships of 300 gross tonnage and upwards and passenger ships irrespective of size shall be fitted with an echo-sounding device, or other electronic means, to measure and display the available depth of water.
IMO PERFORMANCE STANDARDS FOR ECHO SOUNDING DEVICE
Every Echo sounding device used on ship should have following performance standard
- Under normal propagation and sea bed reflectibility conditions the equipment should be capable of measuring any clearance under the transducer between 2 m and 200 m.
- The equipment should provide a minimum of two range scales one of which, the shallow range, should cover a range of 20 m, and the other, the deep range, should cover a range of 200 m.
- The function of range scale selection should be directly accessible. The settings for the following functions should be recognizable in all light conditions: range scale , and preset depth alarm.
- The scale of display should not be smaller than 5.0 mm per meter depth on the shallow range scale and 0.5 mm per meter depth on the deep range scale.
- The primary presentation should be a suitable graphical display which provides the immediate depth and a visible record of soundings. The displayed record should, show at least 15 min of soundings. Other forms of display may be added but these should not affect the normal operation of the main display.
- It should be possible to record on paper recording or other means the information about: the depth(s), and the associated time for 12 h. There should be means to retrieve the recorded information.
- The graphical display should be capable of showing:i. depth marks at intervals not larger than one-tenth of the range/scale in use; andii. time marks at intervals not exceeding 5 min.
- If paper is used for recording either by marks on the recording paper, or by other means, there should be a clear indication when the paper remaining is less than 1 m.
- The pulse repetition rate should not be slower than 12 pulses per minute on the deep range and 36 pulses per minute on the shallow range.
- Output(s) should be available from which depth information may be supplied to other equipment such as remote digital displays, voyage data recorder and a track control system. These outputs should be digital, serial communication, facilities which should comply with the relevant international standards.
- More than one transducer and associated transmitter-receiver may be fitted. If more than one transducer is used:i. means should be available to display the depths from the different transducers separately.ii. a clear indication of the transducer(s) in use should be provided.
- The performance of the equipment should be such that it will meet the requirements of these performance standards when the ship is rolling + 10° and/or pitching + 5°.
- Based on a sound speed in water of 1,500 m/s, the tolerance of the indicated depth should be either: - + 0.5 m on the 20 m range scale, respectively + 5 m on the 200 m range scale; or - + 2.5% of the indicated depth, whichever is greater.
- An alarm signal - both visual and audible with mute function - should be provided when the water depth is below a preset value.
- Alarm signals, both visual and audible (with mute function) to the navigator on the watch should be provided to indicate failure or a reduction in the power supply to the echo sounder which would affect the safe operation of the equipment.