Prior to multibeam sonar surveys

Underwater inspections were mainly performed by divers prior to introducing faster and safer 3D survey methods. Research and development was launched in order to gain more conclusive inspection results.



Sonar systems are mainly used for seabed mapping, navigating and for fishing purposes. VRT shifted its focus from the seabed onto vertical structures early on. The current survey method is based on a combination of high-performance Multibeam Echosounders (MBES) and patented inventions.


Tactical knowledge

The founders of VRT Finland Ltd. are pioneers in the sonar scanning of structures. Civil engineers and structural inspectors by trade, they have surrounded themselves with professionals from the construction industry, land and hydrographic surveying, R&D, software development and marketing.


Unique software

Sonar survey data is generally only processed with programmes designed for seabed scans. VRT has built a unique software and an online service that focuses on providing clear and detailed visualisations for our customers.

Benefits of the VRT method in inspecting underwater structures

Our technology merges the best of other methods: the safety, scope and the speed of sonar seabed surveys and the precision of utilizing divers.

We use R2Sonic and Kongsberg Maritime Multibeam Echosounders combined with our own, patented inventions specifically designed for vertical structures. Our fleet includes manned survey vessels and an unmanned surface vehicle (USV). Using a VRT survey vessel we can scan up to one kilometre of quay or bridge structures per day.

Our equipment also includes a Leica laser scanner for mobile surveys above water level. All of our survey methods result in a comprehensive 3D point cloud model. It can be processed into building information models (BIM), visualised images and CAD drawings such as depth charts, cross-sections or elevations. Each survey site is different—we will recommend the most beneficial way for digitising yours.

The inspection results include pinpointed damages and observations. We assess the severity of damages to help you with upcoming decisions on the maintenance of your site.

Regular inspections prolong the service life of infrastructures and help prevent costly surprises.

VRT Multibeam Sonar Inspection


Other Survey Methods

Process—step by step

Personalised and reliable service


Leave us your details and we will contact you as soon as possible.

Step 1

Our surveyors arrive at the site on the agreed date. We swiftly re-calibrate the equipment and start the inspection.

Step 2

We send the survey data directly into post-processing. Any possible distractions, such as fish, are cleaned out. The point cloud data is positioned to your local coordinate and height systems. Our inspectors will then analyse and report the findings.

Step 3

An information package is delivered containing comprehensive reports, detailed visualisations, CAD drawings and 3D models—tailored to your needs.

Contact Us

VP Business Development

Mikko Kolehmainen

+358 50 394 7230