In Subsea leak detection

ALD-Acoustic Leak Detector Inspection technique: TOWFISH



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ALD® Towfish inspection mode

The pipeline acoustic leak detector ALD® – towfish mode – enclose the hydrophone into an hydrodynamic body “fish” designed to be towed by a vessel and gets data on board trough an electromechanical cable.
This technique reduce drastically the cost of inspection because of the high daily productivity and of the limited requirements for the support vessel (no DP required) but is only applicable in shallow water.


The pipeline acoustic leak detector is mainly composed by:

• subsea sensor including an acoustic transducer, a depth gauge and an electronic data processing unit

• transmission and towing line to take the data on the vessel

• receiver for hardware processing

• PC based software to analyse and display the results

The underwater acoustic leak detector ALD® towed fish includes a custom made acoustic sensor, the pre-processing electronics, an hydrodynamic body and a depth gauge.
It can be effectively used for pipeline monitoring.

Technical specifications


  • length: 1110 mm
  • diameter: 108 mm
  • weight in air: 12 kg
  • weight in sea water: 10 kg
  • tow cable length: 250 m
  • frequency range from 1 to150 kHz  
  • acoustic sensitivity -165dB re 1V/uPa
  • max operative depth 80m
  • survival depth 200 m

Accessories and optional configurations

In this configuration the following optional sensor can be installed: dye detector, crude oil detector.


Product sheet – ALD

ALD track record