Ultrasonic Thickness Gauge, Underwater, Model Mini ROV by Cygnus

Underwater ultrasonic digital thickness gauge. Designed to mount onto small inspection ROV's.


The Cygnus Mini ROV Mountable thickness gage has been specially designed to be mounted onto small observation ROVs with or without a manipulator facility. Built in conjunction with VideoRay, this mountable subsea thickness gage will allow the operator to carry out an ultrasonic thickness measurement in areas that have previously been unfeasible using larger ROVs or divers. The multiple echo thickness gage measures metal thickness and corrosion without removing protective coatings.

Dedicated software displays the time, date and thickness readings on the surface which can all be stored or logged. Alternatively, an optional Topside Repeater (TSR) is available which has the facility to display the thickness measurements remotely and overlay them on to a video signal. This allows the measurements to be superimposed on the ROV camera’s monitor screen. 

The unit is pressure tested to 1,500 ft (500 m).  


  • Oil rigs
  • Wind turbines
  • Ships
  • FPSO underwater
  • Cygnus Mini ROV Gauge
  • Probe cable with marinised remote probe 0.95 m (3 ft)
  • Sealed 4-way connector with fly lead including 9 way connector
  • RS-422 to RS-232 converter
  • Test cable
  • Cyglink Data Logging software
  • Membrane couplant for the UT probe
  • Spare membranes for the UT probe
  • Membrane locking ring key
  • Spare O-Rings for ROV
  • 15 mm (1/2") test block
  • Operation manual
  • Carry case
  • Silicone grease
  • Optional Topside Repeater with video overlay facility kit.


Features of MiniRov Mountable Gauge

  • Designed specifically to mount onto small observation ROV’s
  • Supplied with CygLink software to display and log thickness measurements from the ROV on a computer at the surface which can be saved to a file and printed out
  • CygLink has two data logging facilities: Quick Log for simple recording of thickness measurements and Structured mode with four templates available - Single Point, Multi Point, Grid Point and Key Point
  • The Cygnus Top Side Repeater (TSR) is available as an option and has the facility to display the thickness measurements remotely and overlay them on to a video signal. This allows the measurements to be superimposed on the ROV camera’s monitor screen.
  • Easy calibration at the surface via CygLink software or Top Side Repeater (TSR) unit
  • Optional dedicated probe holder to allow measurements on curved or flat surfaces
  • Only one twisted pair is required to transfer the data to the surface.

Benefits of Cygnus 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.


Materials  Sound velocities between 1000 m/s and 9995 m/s
Measurement Range in Steel  3 mm - 250 mm with 2.25 MHz probe
 2 mm - 150 mm with 3.5 MHz probe
 1 mm - 50 mm with 5.0 MHz probe 
Accuracy  0.1 mm when calibrated in accordance with Cygnus Instruments calibration procedures
Resolution  0.05 mm
Probes  Single crystal soft-faced compression
 13 mm - 2.25 MHz, 3.5 MHz or 5 MHz
Power  7.0 - 30 V dc @ 150 mA (max)
Display  (Not included) PC or Laptop with VGA
Size  160 mm x 62 mm
Weight  19.4 oz (550 g)
Operating Temp  4°F to 122°F (-10°C to +50°C)
Approvals  RINA Type Approved
Testing  Tested to 1,500 ft (500 m) depth
Communications  RS-422, Simplex Single Pair, 2400 Baud
Compliance  British Standard BS EN 15317:2013
Environment  RoHS, WEEE compliant
Warranty  3 years on gauge, 6 months on probe


CygLink Software

CygLink is a Windows® application for PCs that allows remote viewing, control and data logging for the Cygnus Mini ROV gauge. CygLink displays the
thickness measurements in real-time and these can then be logged.

Settings within the gauge can be controlled remotely through CygLink, including calibrating the gauge to a known thickness and inputting a velocity of sound for the material being tested. There is also the option to choose the velocity from a list of common materials.

Each recorded measurement can have pre-set comments and/or a manually typed note added. 

The data logged measurements can be recorded in a Linear List or a TwoDimensional Grid. Each survey can have separate groups of measurements within it and a “Reference” and “Minimum” thickness set.

Reports can be created either as a .pdf or the data exported to a .csv file. The measurements can also be represented graphically. 


Top Side Repeater (TSR) - Optional 

The Top Side Repeater is a small display unit that can be used to display the thickness measurements sent from the Cygnus Mini ROV gauge to the surface.

Kit includes data and video cables. 

TSR Video Overlay Facility 

The Top Side Repeater can also superimpose the thickness measurements on to a composite PAL or NTSC video signal to display it on a monitor screen and/or the video recording of the survey. This provides a thickness measurement that can be linked to a position or place in the video recording.