Cygnus Underwater Ultrasonic Thickness Meter

Cygnus Underwater Ultrasonic Thickness Meter


The Cygnus Underwater is the original diver-held subsea Multiple-Echo ultrasonic thickness gauge. It was designed for use by divers undertaking subsea maintenance and surveys 3 decades ago… and today it is still an industry standard. Ideal for hull UTM inspection, civil engineering, marine structures, offshore platforms, underwater structures, e.g. bridges, tanks, canal locks, subsea pipelines and equipment, UWILD or IWS class surveys.


  • Multiple-Echo mode for accurate, through-coat measurements as specified by Classification Societies
  • Deep Coat mode ignores coatings up to 0.8 inch thick (upon request)
  • Heavy duty sealed unit with double ‘O’ ring protection
  • Rugged, durable, shock-proof construction
  • Bright LED display when in areas of poor visibility
  • Easy & stable calibration – no zero adjustment
  • Echo strength indicator to aid measurement
  • Two rechargeable battery packs with charger
  • Auto-Probe Recognition (APR).

Benefits of Multiple Echo

  • Measures remaining metal thickness on corroded and coated structures
  • All measurements are error checked using 3 return echoes to give repeatable, reliable results
  • Accepted by all major classification societies
  • Greatly reduces inspection time and costs
  • Echo strength indicator to aid measurement

Technical Specifications

Cygnus Underwater Specifications

Materials Velocities between 0.0800 to 0.2780 in/us – covers virtually all common engineering materials
Measurement Range in Steel 0.040" – 10" (1 - 254 mm) depending on selected transducer and configuration, material and temperature
Accuracy ±0.1 mm or 0.1% of thickness measurement, whichever is greatest, when calibrated in accordance with Cygnus Instruments calibration procedure
Resolution 0.005" or 0.002" (0.127 or 0.051 mm) selectable
Probe Options Single crystal transducers
Power 2 x rechargeable NiMH battery packs
Battery Life 2 x 20 hours continuous measuring (with fully charged battery packs)
Display Large, bright LED display
Size 9.4" x 3.4" (239 x 86 mm) including battery pack and transducer head
Weight 35 oz. (992 g) including batteries 
Operating Temp. 14°F to 122°F (-10°C to 50°C)
Environmental Protection IP68 continuous 984 ft. (300 m) rating
Standards Designed for EN 15317
Compliance CE, UKCA, RoHS

Cygnus Underwater Kit Includes

  • Cygnus Underwater gage body
  • Lanyard and molykote and tommy bar
  • 2 rechargeable NiMH battery packs
  • Battery charger and leads
  • Transducer for Cygnus Underwater, supplied as nosecone assembly with 1m cable
  • Membrane couplant
  • Accessories: spare o-rings; spare membranes, membrane locking ring key, 15mm test block; torque (Tommy) bar; calibration jumper lead


To compliment our ultrasonic thickness meters we offer a range of ultrasonic transducers. The performance of any ultrasonic thickness meter relies heavily on the transducer and its suitability to the material being measured. Therefore, selecting the right transducer is vital. All Cygnus SINGLE CRYSTAL transducers are made from stainless steel and include replaceable membranes for long life, requiring no zeroing and have a high linear accuracy.


 Probes List 

Additional Options

  • Topside Repeater Remote Display Unit - The Cygnus Topside Repeater is a remote display unit connected to the gage with an umbilical cable. It displays the thickness measurements at the surface in real-time during the survey.
    • Option A: Palm-held Topside Repeater (TSR) 
    • Option B: CygLink software (Windows based) for data logging and remote display
  • CygLink Computer Software - CygLink is a Windows® based application used to display, log and transfer thickness measurements at the surface. The software can generate PDF reports and export to CSV files, allowing for after-the event analysis of logged measurements. Designed for Windows 7 and above.

Product Literature

Description Part # Saved Price Select Option Add to


Cygnus Underwater mk4 UTG Kit (without probe) Includes: Unit, Lanyard and Molykote and Tommy Bar, 2 rechargeable NiMH battery packs w/battery charger and leads, membrane couplant and hard case UT-CY-001-9933/4 $4,057.00


Probe S2C 2.25 MHz 1/2" (13mm) w/1 m cable for Cygnus Underwater / Mini ROV UT-CY-001-9340 $876.00
Probe S3C 3.5 MHz 1/2" (13mm) for Cygnus Underwater UTG UT-CY-001-9357 $935.00

Optional Accessories

Upgrade Kit A for Cygnus Underwater to add Topside Repeater Unit (TSR) UT-CY-001-7133A $1,378.00
Upgrade Kit B (CygLink) for Cygnus Underwater to add surface computer logging UT-CY-001-7133B $715.00
Umbilical Cable for DIVE / UW / ROV to Topside Repeater (TSR) Kit (per meter) UT-CY-001-0415 $4.19