Echo-sounder

Data on the numbers and biomass of the total stock of species examined in the Black Sea provided a basis for computing their production and balance. Efficient fishing devices and echo-sounder records were employed. The study allowed the determination of productivity of fish and of the effect of substance and energy consumption on population level over the whole annual cycle and for each species. It was also possible to evaluate the share contributed by the total stock of abundant fish species to the total cycle of matter and energy in the whole of the Black Sea. 

Fig. 10 Bathymetric profile along a cross-section of the strait connecting the western and the eastern basins (the coordinate of the northern extremity of the cross-section is 45°44.82 N, 59°12.96 E). Echo-sounder data collected in October, 2005, Survey 5(2)...

Fig. 13. Structure of the bottom of Long Island Sound revealed by acoustic reflection profiles made with 7-kHz acoustic pulses. (Upper echo is produced by a 2(X)-kHz echo sounder.) (a) Section of end moraine capped by boulders and almost buried by marine mud. (b) Thick deposit of marine mud in central Long Island Sound on top of outwash sand with reflector above thought to be surface of lacustrine deposits, (c) Sand-to-mud transition zone in central Long Island Sound. In all records each division on the vertical scale is 600 mm.

With the introduction of the rosette sampler and the echo sounder, choosing the depth at which a sample is to be taken is a simple exercise in chart reading. Samples can be taken at any specified depth or in any specified water mass. Using much less sophisticated equipment on a cruise in the South Pacific [167], we were able to take water samples in the Antarctic Intermediate Water from 63 °S almost to the Equator, in order to demonstrate a horizontal continuity and vertical discontinuity in organic particulate content associated with a particular water mass. 

Echo sounders were originally developed as an echo-ranging device immediately prior to World War I in 1913 to locate icebergs after the Titanic disaster. During the war, an effort was made to adapt the device to locate submarines. After World War 1, the device was adapted to measure ocean depths. This technology permitted accurate depth determination from a moving ship. This allowed for large areas to be surveyed quickly and with a minimal cost. 

German Meteor Expedition to map South Atlantic Using Echo Sounders... 

In areas where detailed bathymetry is required, a precise multibeam echo soimder may be used. There are many considerations when evaluating such a system, such as the vertical accuracy, resolution, acoustic beamwidth of the transmit/receive beam, and the acoustic frequency of the transducer. Most hydrographic echo sounders are dual frequency, that is, they have a low-frequency pulse (typically aroimd 24 kHz) that can be transmitted at... 

A minelayer with a remotely controlled submarine, one-manned submersible, was chartered. It was equipped with scanning sonar, echo sounder, low-light cameras, headlamps and manipulators and conducted by cable. The submarine was brought down to the group of five wrecks and a video film was made. 

Underwater Sound. Applications for underwater acoustics include devices for underwater communication by acoustic means, remote control devices, underwater navigation and positioning systems, acoustic thermometers to measure ocean temperature, and echo sounders to locate schools of fish or other biota. Low-frequency devices can be used to explore the seabed for seismic research. 

Plastics are used successfully in instruments to determine depth, the velocity of currents, temperature, and as echo sounders. Parts operating to depths of 4,500 m (15,000 ft.) include molded polystyrene rotors, neutrally buoyant polyethylene control vanes, PVC... 

A perfectly good product can be mined or have its life curtailed by incorrect installation. If installation is by the manufacturer this is a form of quality control lapse whereas if installation is by the user or a third party it could be considered misuse. In failure analysis, wrong installation is often the first defence from the supplier. One of the arguments advanced when a largely polymeric echo sounder unit was lost from the hull of a yacht (resulting in sinking of the vessel) was that it had not been attached properly. However, one would expect it to have pushed inwards not outwards due to water pressure. 

In 2013 the full scale measurements of scour holes formed due to bow thrusters and main propellers action in front of the quay wall were performed in Port of Rotterdam. After each departure the bathymetry near the quay was measured using a multi-beam echo sounder. 

The presented methods are used in ports to predict the degradation processes however due to the operation of large vessels in divergent operational conditions and relatively cheap monitoring methods the inspections using a multi-beam echo sounder in many ports are carried out in month periods. 

All soundings shall be carried out by means of a recording trace dual frequency echo-sounder with sufficient sensitivity to permit measurement of the bed levels to an accuracy of +/-100 mm. The echo sounding equipment shall be regularly calibrated by means of a sounding plate. 

B.4.2 Multibeam sonar or multibeam echo sounder (MBES) 578... 

A typical non-interpolated result of a single beam survey is displayed in Figure B.2. Multibeam echo sounder... 

For bathymetry measurements carried out with a single beam echo sounder the total length of the survey lines equals the sailing distance. 

Depending on the aim of the bathymetric survey, the equipment and line density is chosen. For an overall bathymetric survey that is carried out for example on the North Sea, a line density of one hne every 25 or 50 metres using a single beam echo sounder can be sufficient. On the other hand, in case of monitoring the transport behaviour of so-called sand waves much more detail is needed and hence the use of multibeam echo sounding to obtain a full coverage of the sea bottom is advised. 

The multi beam echo sounder is used in coastal areas where water depths range from about 2 metres below the ship up to about 1000 metres or more. Deep echo sounding with a multi beam system is possible deeper than 1000 metres, but the data coverage will decrease due to the travel time of the acoustic waves. This causes a loss of sea bottom detail (an important aspect of multi beam). For deep echo sounding, a single beam echo sounder is generally preferred because it is easier to use than multi-beam echo sounders. 

The multibeam is sometimes referred to as Swath echo sounder. The multibeam is in principle equal to the side scan sonar and the sub-bottom profiler, except that... 

Sediment echo sounders (SES) use piezoelectric pingers as electroacoustic converters. 

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