Cygnus FMD System for Diver

Ultrasonic Flooded Member Detector

Designed specifically by Cygnus for Flooded Member Inspection (FMI) – using decades of experience of ultrasonic testing in the subsea inspection industry, the Cygnus FMD system detects ingress of water in subsea structural members using ultrasound. This ultrasonic testing (UT) solution boasts intelligent software and cutting edge electronics combined with a truly simple to use interface to give a clear DRY or FLOODED result that can be trusted.

Once the subsea unit is deployed by the diver, the Cygnus FMD system runs a test using the FMD software at the surface; a simple DRY (Green) or FLOODED (Red) result will be shown, alongside the waveform (A-scan) for further verification. The results are logged for analysis and for reporting as PDF and Excel.


The innovative and agile transducer handling solution “self-aligns” with the surface and ensures correct contact with the target member – regardless of what angle or direction of approach. When a diver only has one hand free, this aspect of the Cygnus FMD really sets it apart from the competition.

Only when the next intelligent element of the system is engaged (a contact sensor telling the team at the surface that good, appropriate contact has been made) will a simple DRY / FLOODED result be displayed and logged.


Due to the clever and failsafe aspects of the system’s design, the Cygnus FMD is very easy to learn and can be used by owners or operators with varying levels of UT experience. The need for specialist external contractors is removed.


The FMD equipment is designed to the highest standards, supported by a three year warranty.


Cygnus is an ultrasonic specialist. 4 decades of industry experience and design expertise combine to make this system the most advanced, effective and reliable Ultrasonic FMD System available.

The purpose-designed algorithm simultaneously uses

– an advanced peak detection algorithm

– low distortion / low noise data acquisition

– advanced signal processing

all of which ensure the highest level of Probability of Detection (PoD) and the elimination of false readings.

The FMD system only allows for a measurement to be taken when the contact sensor detects transducer contact – ensuring reliable results every time. The reporting software will indicate at the surface if the transducer loses contact during inspection.

The system features a System Test Function that ensures the system’s reliability before deployment.


The transducer solution is compact and allows for tests to be done on hard to reach areas such as K nodes where other inspection methods cannot operate.

A selection of options is available to suit working depths and varying requirements.

This FMD system is also deployable by ROVs.

Transducer0.5 MHz high power piezo composite transducer – single element
Measuring Range200 – 2000 mm member diameter
Resolution1 mm


Diver Communications PSU110-240 AC 50/60 Hz @ 1A (max)
ROV Power Supply12 to 24 volt D.C @ 60mA


DigitalRS232 & RS485
Baud Rate115,200
Date CaptureOn demand 3 shot and varying gain levels
Diver Data LinkRS485 half – duplex
ROV Date LinkRS232 full – duplex suitable for fibre multiplexers


Acetal Electronics Body0.9 kg (95 mm (diameter) x 115 mm (height))
Stainless Steel Electronics Body4 kg (95 mm (diameter) x 115 mm (height))
Acetal Transducer Handler2.5 kg (140 x 170 x 130 mm)
Stainless Steel Transducer Handler4.7 kg (140 x 170 x 130 mm)
120m Umbilical Cable23 kg (340 x 450 x 555 mm)
350m Umbilical Cable87 kg (450 x 600 x 930 mm)
50m Deck Cable13 kg (290 x 380 x 490 mm)
Depth Rating300 msw
Operation Temperature0°C to +75°C
Storage Temperature-40°C to 55°C
Cable Protector
– Provides extra cable protection and an attachment point for divers
Self Aligning Transducer Handler
– Tough Stainless Steel or
– Lightweight Acetal
Handle Option
– Stainless Steel D-Handle
Communications PSU
– Provides power and communications to the diver
Umbilical Cable
– 120m length
– 350m length
System Test Tank
– Used to run a full system test of the FMD system

1 review for Cygnus FMD System for Diver

Louis P

Nov 25, 2020 11:27 AM

The new Cygnus Ultrasonic FMD System was perfect for our recent application. Our technicians found the software to be very easy to use with features that ensured a quick and reliable result. It’s a great addition to the Westerton Access capability, offering FMD inspection from the Falcon ROV

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