Unmanned Aerial Vehicles for Survey of Marine and Offshore Structures: A Classification Organization's Viewpoint and Experience

Abstract

This paper discusses the benefits of using Unmanned Aerial Vehicles (UAVs) as inspection tools to support surveys of marine and offshore assets, from a class organization's viewpoint and understanding, based on industry case studies and experiences for both internal and external structure surveys. Capabilities and limitations of using UAVs are compared to current survey methods. Finally, possible future uses of this technology will be discussed. Some specific inspections for marine and offshore assets, such as those conducted at height or in confined spaces, are typically performed by surveyors. These inspections can be expensive, time consuming, and disruptive. This paper presents key challenges driving the need for UAV inspection, and benefits offered by this new technology. General acceptance criteria and requirements of UAV inspection (e.g., data acquisition), based on previous industry experience, are introduced. Available UAV systems are presented, with a brief introduction of typical UAV types. General performance and lessons learned, based on previous UAV field tests, are summarized. Two case studies further highlight field test results. Also, the paper discusses existing and potential data post-processing methods (e.g. regression analysis), and how these methods leverage UAV technology in structure monitoring and inspection. The use of UAVs can help reduce the risk associated with the above mentioned inspections by reducing hazard exposures for workers. Use of UAVs can also have a positive impact on operational activities through increased inspection frequency, improved inspection efficiency and better data collecting capability. With proper utilization, the data collected by UAVs can augment and complement such technologies as photometric processing, structural condition monitoring and failure recognition. All of these can help refine shipyard specifications, enhance repair plans and reduce overall cost by providing greater knowledge of the asset's condition. Currently, the mainstay of UAV inspection is the High-Definition (HD) camera, for photograph and video data collection. However, the impact of emerging technologies on UAVs such as infrared emission sensors, thickness gauging tools, LiDAR scanners, etc., to the Class survey scope requires further study and research.