ZAVOD ZA MINERALNE SIROVINE MARINSKU GEOLOGIJU
Field equipment
Contact: dr.sc. Ozren Hasan, dipl. ing. geol.
Side-scan sonars (SSS)
The Humminbird 999 HD SI side-scan sonar (SSS) emits fan-shaped acoustic pulses towards the seabed with a frequency of 80 and/or 200 kHz. The equipment enables the imaging of the seabed morphology. In combination with sediment samples, this method is often used for differentiation of the hard or soft seabed substrate and enables the mapping of larger areas of the seabed.
The Humminbird Helix 10 side-scan sonar (SSS) is a newer generation of a side-mounted side-scan sonar. This device works at various frequencies (50/83/200/455/800/1200 kHz), which enables single-beam depth measurement up to 365 m, while the operation of the side-scan sonar at frequencies 455 kHz and 800 kHz enables bottom imaging up to depth of 120 m.
Both side-scan sonars are characterized by good mobility and the possibility of working on various vessels, as well as working in a very shallow environment. The data recorded by these devices are subsequently processed in the computer program Reefmaster 2, which enables the creation of bathymetry model and side-scan mosaics.
Side-scan sonar Humminbird 999 HD Si.
Interpretation of a mosaic made with side-scan sonar for the archaeological research in the Kornati Channel.
Map of the intensity of return waves at the archaeological site of Morinje, on which lighter colors show stronger reflections representing the walls, while darker colors represent the soft silty seabed.
Side-scan sonar “C-MAX C2” is used to create an acoustic image of the seabed. It consists of a transmitter and a receiver that are placed together in a device shaped like a torpedo that is dragged on a cable, through which the device communicates with a control unit on the vessel. The device works at frequencies of 100 or 325 kHz, and has built-in sensors for orientation, roll and pitch, and a water depth sensor. The cable for connecting the control unit to the transmitter is 300 m long and is mounted on an electric winch. The device also has a pulley that is used to measure the length of the unwound cable. The device is controlled using MaxView software installed on a Getac rugged laptop. The width of the beam with which it records the seabed is from 50 m to 1000 m. The working depth of the device is a maximum of 2000 m, and during navigation it is kept as close as possible to the seabed, in a range of about 10% of the beam width. Data postprocessing is done in SonarWiz software.


The C-MAX C2 side-scan sonar in the sea.
Image of the seabed acquired during recording.