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 our owns inventions specifically designed for vertical structures. Our fleet includes agile manned survey vessels designed for tight spots. Using a VRT survey vessel we can scan up to one kilometre of quaybridge, pipeline, jetty or dam structures, just to name a few, per day.

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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.

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The inspection results, with 3D data interpreted by our licensed experts, include pinpointed damages and observations. We assess the severity of damages to help you with upcoming decisions on the maintenance of your site. We use GISGRO online service to easily deliver the results to the client.

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

Do you want to know more about our technology? Contact us – we are happy to tell you more!

VRT Multibeam Sonar Inspection


Other Survey Methods

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 GISGRO that focuses on providing clear and detailed visualisations for our customers.

Process—step by step

Personalised and reliable service

Step 1

Leave us your details and we will contact you as soon as possible to plan the survey and to define the inspection areas with you.

Step 2

Our surveyors arrive at the site on the agreed date. We swiftly re-calibrate the equipment and start the inspection without any disturbance to your operations.

Step 3

We send the survey data directly into post-processing, where our experts clean out any possible distractions. Our inspectors will then analyse and report the findings.

Step 4

We deliver you a fully processed information package through GISGRO online tool, with an easy and independent online-access to all data, containing comprehensive reports, visualised 3D data and expert observations.

Interested in our services? Contact us!

Karri Kolehmainen & Ville Mäkeläinen

Karri Koistinen

+358 40 0604927



Ville Mäkeläinen

+358 44 513 2222


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