Areas of operation
Long-Range Pipeline and Tunnel Inspection
Subsea Tech designs and builds its own equipment. We select the system according to the pipe’s diameter, length and water level.
Structures inspected
- Sea outfalls and wastewater treatment plant discharges
- Headrace and tailrace tunnels of hydroelectric plants
- Drinking water and seawater pipes, up to Ø 2,000 mm
- Siphons and storm overflows
- Partially flooded tunnels
- Industrial site networks and oil pipelines
Data provided
- Video and sonar imagery of the entire length
- Position of each anomaly, measured by odometer
- Cross-section profiles and ovality checks
- Silt level
- Condition of the civil structure: walls, joints, repairs
Our inspection equipment
Small diameters
Endoscope, UVSIP camera
For pipes from 25 mm, dry, partially or fully flooded, up to 100 m.
Flooded pipes
These ROVs inspect fully flooded pipes from Ø 300 mm, up to 3 km. They carry HD video, an acoustic camera and a profiling sonar.
Very long distances
Battery-powered robot for pipes from Ø 500 mm, up to 5 km. It records images on board, with no live video feed.
Dry or partially flooded pipes
Pipescanner, Lantana, NAVIGOH
The Pipescanner, a motorised crawler, inspects dry pipes from Ø 330 mm. Lantana and NAVIGOH record the dry and submerged sections at the same time, up to 5 km for NAVIGOH.
Use cases and missions
Veolia · Palavas-les-Flots (34) · 2024-2025
MAERA sea outfall
Ouvrage
Émissaire de Ø 1 600 mm, inspecté en trois campagnes sur environ 1,9 km au total. Chaque campagne part d’un seul regard d’accès et couvre plusieurs siphons. La visibilité était inférieure à 50 cm.
Equipment
Mini TORTUGA with an Oculus acoustic camera and an Imagenex 831-A profiling sonar. The ROV, weighing about 20 kg, is lowered by hand through the manhole and piloted from the control van. From each access point it inspects upstream, then downstream, in half a day.
Expected results
Position, longueur et hauteur des dépôts dans chaque siphon. Diamètre utile mesuré sur tout le linéaire, qui permet d’évaluer l’encrassement des parois. Vérification de l’état structurel de la conduite. Des campagnes successives permettent de comparer les tronçons entre eux.
EDF · Les Mées (04) · 2020 & 2025
Les Mées tunnel, 2.7 km
Ouvrage
Tunnels, drain valves and tunnel walls over 2.7 km, with few access points, local currents and very low visibility.
Equipment
TORTUGA with a 3,300 m fibre-optic tether, a dual-frequency Oculus M750d acoustic camera and an Imagenex 831A profiling sonar.
Expected results
Continuous inspection of the full length from a limited number of access points. Detection and sizing of defects from about 20 mm, across the full cross-section, including in turbid water. Silt assessment.
SEMM · Marseille (13) · 2021 & 2023
Assassin tunnel, Marseille canal, 3,400 m
Ouvrage
Partially flooded tunnel. The dry crown and the submerged invert had to be inspected in a single pass.
Equipment
NAVIGOH, an energy-autonomous float developed for this project. Two 180° 4K cameras and LED lighting record the crown, while a profiling sonar and an imaging sonar survey the invert. The canal current carries it forward, and an electric winch controls its speed and measures the distance travelled.
Expected results
Crown and invert surveyed in a single pass. Any defects identified and located along the tunnel, using the winch measurement.
H2O ProServices · Alger (Algérie) · 2019
Two Ø 2,000 mm drinking water pipes
Ouvrage
Two pipes, 1,600 m and 1,100 m long, requiring visual inspection and ovality checks.
Equipment
Torpedo, held against the pipe crown by skids. HD camera, additional external camera and winch with odometer.
Expected results
Images of the inner wall along the full length, ovality check and position of each anomaly measured by odometer. This data is used to plan rehabilitation work.
References
Alsachimie · Chalampé, France · 2025
Industrial site pipe network
SERAMM · Marseille (13), France · 2022 & 2025
Partially flooded stormwater network, cours Jean Ballard
SCP · Rousset (13), France · 2025
Video and 3D scan of two 200 m shafts
SEMM · Aubagne (13), France · 2024
Magnans siphon
Commune de Capbreton (40), France · 2021 to 2025
Profiles of the sand transfer pipeline
Bonna TP · La Seyne-sur-Mer (83) · 2023
Internal inspection of the Amphitria wastewater plant outfall
TETIS · Carnac (56), France · 2022
1,060 m discharge outfall
EDF PEI · Bellefontaine, Martinique · 2019
Two Ø 1,400 mm seawater pipes, 480 m long
SABOM · Bordeaux Métropole · 2022
Flooded and partially flooded sewers
Saipem · Port Said, Egypt · 2018
Internal inspection of 2.2 km of submerged pipeline
Veolia · Lyon (69), France · 2022
DN 1000 pipe over 230 m, with thickness measurements
Over 80 pipeline inspections since 2010 for public and private clients.
FAQ
What pipe lengths and diameters can you inspect?
The equipment is selected according to the pipe’s diameter, length and water level:
| Type | Name | Min. diameter | Max. length | Configuration |
|---|---|---|---|---|
| Camera | Endoscope | 25 mm | 30 m | Dry, partially flooded, fully flooded |
| Camera | UVSIP | 70 mm | 100 m | Dry, partially flooded, fully flooded |
| Motorised crawler | Pipescanner | 330 mm | 250 m | Dry, partially flooded |
| ROV | Guardian | 300 mm | 400 m | Fully flooded |
| ROV | Mini TORTUGA | 400 mm | 700 m | Fully flooded |
| ROV | TORTUGA | 500 mm | 3 km | Fully flooded |
| ROV | Lantana | 400 mm | 250 m | Partially flooded |
| AUV | Torpedo | 500 mm | 5 km | Fully flooded |
| AUV | NAVIGOH | 600 mm | 5 km | Partially flooded |
Can you work in a current or with no visibility?
Our ROVs can inspect in currents up to 1 m/s (mini-ROV) or 2 m/s (TORTUGA). With no visibility, inspection is carried out by sonar, which records the network geometry (diameter, bends, branch connections), silt levels and any objects.
What defects and measurements?
Full HD cameras detect cracks, corrosion, deposits, blockages and connection defects. Depending on requirements, our equipment also measures silt height, ovality and the thickness of metal walls.
How do you locate anomalies, and what do you provide after the inspection?
The distance travelled is measured to within ±1%, i.e. 1 m per 100 m. The position of a defect around the circumference is estimated from the image. We provide the inspection video, the measurements, a defect report (position, type, size) and, if required, a plan of the network.
Request an inspection
Please fill in the form below to receive a quote or more information. Fields marked with (*) are required.
