Focus on the smf
the multibeam sounders on the Pourquoi pas ?
The R/ V Pourquoi pas? will be equipped with two multibeam sounders provided by the Danish company RESON for surveying the seabed and under sea cartography:
- a 100kHz system: Seabat 7111, dedicated to coastal hydrographic surveys and exploration of the continental shelf and the top of the continental slope.
- a Seatbat 7150 12/24kHz dual-frequency system. This sounder will have two operating modes:
- a "wide coverage" (12kHz) mode for general exploration surveys at great depths (200/12000 metres), covering a wide swathe (20km),
- a "high resolution" mode (24kHz), for detailed exploration: sites where submersibles will be used, for example surveying sites.
5 x P if P<1000m
20km if P>1000m
Max (1m, 0.3% P)
Seabat 7111 antenna
Seabat 7150 antenna
The acoustic antennae will be installed in a pod suspended under the ship's hull, called a "gondola". This is a heavy structure, independent of the hull, sited a few dozen centimetres from the keel and connected to the hull with streamlined struts.
The shallow-water multibeam sounder will be installed in a fairing infront of the gondola.
The gondola also houses the transducers for the ship's other acoustic equipment:
- Eramer / Triton Elics sediment penetrator (2 to 8kHz)
- Simrad EA600 single-beam sounder (12/38/200kHz)
- RDI Ocean Surveyor doppler current profiler (38/150kHz)
The shape and underside of the gondola of the Pourquoi pas? have been approved during tests on a scale model at the naval dock in the Netherlands.
Data acquisition / processing
In batch processing, the data will be processed using the CARAIBES software package.