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Sub-bottom profiler of the survey boat Haliotis

General presentation

Ifremer has design the general structure of a sub-bottom profiler (SBP) adapted to shallow water acquisitions (water depth < 20 m) for the survey boat Haliotis.

The main features of this SBP are listed below :

  • Acquisition on sandy sediments ® low frequency sounder.
  • Excellent vertical resolution (~20 cm) ® FM signals in the frequency band [1.7, 5.5 kHz].
  • 0 < Water depth < 20 m and reduced draft (40 cm).
  • Acquisition speed up to 7 knots.
  • Source level adapted to reach a penetration depth of about 25 m (absorption a = 0.2 dB/l).
  • Small size and low cost.

The different parts of the emission and reception chains as well as the acquisition system have been validated during measurements performed at Ifremer-Brest seawater tank facilities between May and July 2007. The SBP has been integrated on the survey boat in December 2007 and the sea trials took place near Brest in February and March 2008.

SBP data example

The following SBP profile has been recorded on the survey boat Haliotis during sea trials near Quiberon in April 2010 (profile length ~1.4 km, vertical axis: two-way propagation time in ms).