Overview
What we inspect below the waterline. Upstream faces, spillways, intake towers, scour protection and reservoir floors, surveyed without drawdown. Pier and abutment condition, undermining and scour mapping after flood events, culvert barrels and outfalls. Quay walls, sheet piling, jetty piles, lock gates, hulls and moorings, with thickness readings on submerged steel. Service reservoirs, intakes, screens and pipework, inspected live with potable-ready equipment protocols. Storage tanks, wet wells and shafts where entry by a person is slow, costly or simply not safe. Cooling water intakes, outfalls and hydro structures, inspected without interrupting generation.
What we survey
Dams & reservoirs
Upstream faces, spillways, intake towers, scour protection and reservoir floors, surveyed without drawdown.
Bridges & culverts
Pier and abutment condition, undermining and scour mapping after flood events, culvert barrels and outfalls.
Ports & marine
Quay walls, sheet piling, jetty piles, lock gates, hulls and moorings, with thickness readings on submerged steel.
Water utilities
Service reservoirs, intakes, screens and pipework, inspected live with potable-ready equipment protocols.
Tanks & confined water
Storage tanks, wet wells and shafts where entry by a person is slow, costly or simply not safe.
Energy assets
Cooling water intakes, outfalls and hydro structures, inspected without interrupting generation.
How an ROV survey works. The vehicle flies a planned grid over the structure. Imaging sonar builds an acoustic picture even in zero visibility, HD cameras record close-quarters detail, and an ultrasonic thickness payload takes quantified wall readings on steel. Every observation is referenced to position, so the defect you see in the report is the defect your contractor finds on site. Because nobody enters the water, there is no dive plan, no decompression limit and no standby diver. Surveys that would take a dive team days fit into a single visit, and structures that are too deep, too confined or too fast-flowing for divers stop being blind spots.
Measured, not estimated. Visual condition tells you what the surface looks like. It does not tell you how much steel is left. Ultrasonic thickness gauging gives remaining wall on sheet piles, gates and pipework as numbers an engineer can check against the corrosion allowance, and repeat surveys turn those numbers into a corrosion rate. That is the difference between a maintenance plan and a guess. For grids of readings across larger areas, see our corrosion mapping service.
Scan before you repair. That is the standing advice for every Underwater client, and the reason NDTScan reports what the concrete contains before anyone specifies what to do about it.
Services Available Nationwide
- GPR Concrete Scanning Pre-drill and pre-coring surveys, rebar and mesh mapping, post-tensioned tendon detection, void detection, slab thickness and cover estimation and RAAC identification.
- Ultrasonic Testing of Concrete Ultrasonic pulse velocity, pulse echo and SONREB for uniformity, thickness, delamination and compressive strength estimation where GPR alone cannot answer the question.
- Concrete Compressive Strength Assessment Rebound hammer, UPV combined method and managed core extraction to BS EN 13791, with independent reporting for engineering acceptance and building control.
Related Services
Related: ROV inspection services: the fleet, payloads and data in detail; Underwater surveying and inspection and our ROV equipment; Corrosion mapping and UT thickness surveys; Maritime and underwater assets sector; Emergency NDT response for post-flood and impact damage.
About NDTScan
NDTScan is a specialist non-destructive testing company based in Oxford and led by Neil Smuts. Its core disciplines are GPR concrete scanning, ultrasonic testing and in-situ compressive strength assessment, brought together in its concrete scanning and structural condition survey service. NDTScan is a Level 4 UKCSS Operator, the first in the UK to achieve that certification. Underwater and the whole of the United Kingdom are within the company's everyday working area, and all work is reported to a standard suitable for engineering acceptance. RAAC identification is covered on the RAAC surveys page, and steel on the ultrasonic thickness and corrosion mapping page.
Underwater NDT Services
- Dams and reservoirs Upstream faces, spillways, intake towers, scour protection and reservoir floors, surveyed without drawdown.
- Bridges and culverts Pier and abutment condition, undermining and scour mapping after flood events, culvert barrels and outfalls.
- Ports and marine Quay walls, sheet piling, jetty piles, lock gates, hulls and moorings, with thickness readings on submerged steel.
- Water utilities Service reservoirs, intakes, screens and pipework, inspected live with potable-ready equipment protocols.
- Tanks and confined water Storage tanks, wet wells and shafts where entry by a person is slow, costly or simply not safe.
- Energy assets Cooling water intakes, outfalls and hydro structures, inspected without interrupting generation.
Our Services
- Concrete & Structural Integrity
- Drone-Based Aerial Surveying
- Vehicle-Mounted Inspection
- Handheld & Portable Inspection
- Underwater Surveying & Inspection
- Digital Twin & 3D Modelling
- Advanced Data Analytics & Reporting
Sectors We Support
- Aerospace & Aviation
- Education & Public Sector
- Archaeology & Heritage
- Smart Cities & Urban Planning
- Waste & Recycling
- Defence & Security
- Emergency Response
- Construction & Real Estate
- Mining & Minerals
- Agriculture & Environment
- Maritime & Underwater
- Rail & Transportation
- Oil & Gas
- Civil Engineering
- Utilities & Energy
Equipment & Technologies
- IML
- GSSI
- Sylva
- Leica
- Voyis
- Testo
- Hilti
- Cygnus
- Proceq
- MALA GPR
- SlipAlert
- Flyability
- Protimeter
- Matterport
- Saab Seaeye
- Deep Trekker
- IDS GeoRadar
- FLIR Systems
- Sonatest Ltd
- Wagner Meters
- Mistras Group
- Munro Stanley
- Blue Robotics
- DJI Enterprise
- Teledyne Marine
- Quantum Systems
- Argus Electronic
- Fakopp Enterprise
- Eddyfi Technologies
- Olympus Corporation
- FARO
- NavVis
- Trimble
Why Choose NDTScan
Underwater NDT FAQs
Frequently Asked Questions.
Common questions about underwater ndt inspection from NDTScan, answered by the team that does the work.
What structures can you inspect underwater?
Quay walls, bridge piers and abutments, dams and reservoirs, culverts and outfalls, intake structures, sheet piling, jetties, lock gates, ship hulls and submerged tanks. If it sits below the waterline and matters structurally, we can put a sensor on it.
Do you use divers or ROVs?
We are ROV-led. Remotely operated vehicles carry imaging sonar, HD video and NDT payloads into water that is deep, dark, fast-flowing or confined, without putting a person in the water. That removes the cost and risk of dive teams for the majority of inspection work.
Can you measure steel thickness underwater?
Yes. Ultrasonic thickness gauging on submerged steel gives quantified remaining wall thickness on sheet piles, hulls, gates and pipework, so corrosion allowances can be checked against design rather than estimated from visual condition.
What do we receive at the end of the survey?
A structured report: sonar imagery and HD video referenced to position, thickness readings against design values, defect schedules with severity, and clear recommendations. Data can be supplied in CAD-ready and GIS-ready formats for your asset management system.
Can you work in zero visibility?
Yes. Imaging sonar builds an acoustic picture of the structure and the bed around it, so turbid water, night work and silt-laden reservoirs do not stop the survey.