DRONES AND REMOTE SENSING FOR NON-DESTRUCTIVE TESTING OF MARINE CONCRETE STRUCTURES IN THE BALTIC SEA

Marine concrete structures in the Baltic Sea-including breakwaters, piers, and historic fortificationsplay a vital role in coastal protection, navigation, and cultural heritage.Now exceeding their design lives, these assets are increasingly threatened by harsh brackish conditions, freeze-thaw cycles, and environmental contamination.Traditional diver-based inspections are hazardous and offer limited insight into hidden or internal degradation.Recent advances in non-destructive testing (NDT) and remotesensing platforms-particularly those using remotely operated underwater vehicles (ROVs)-enable safer, more comprehensive monitoring.This paper synthesizes current NDT methods (ultrasonic, radiographic, electromagnetic, thermographic), complementary remote sensing (sonar, photogrammetry, satellite), and highlights recent Baltic Sea case studies.Environmental and operational challenges (e.g., biofouling, low visibility, signal attenuation) are discussed, synthesised from field experience, and the possibilities of AI-assisted analysis, digital twins, and next-generation autonomous platforms proposed.Integrated, data-driven diagnostics conclude to extend asset service life and protect underwater cultural heritage across the Baltic.