Are drones the future of marine surveying?
Improving safety, cutting costs, speeding up processes, making access challenges a breeze…just some of the benefits of using Unmanned Aerial Systems (UAS), more commonly known as drones.
For these reasons, drones are quickly becoming a staple of the maritime industry and whilst drones were initially developed for government and military operations, over the next five years, growth in the commercial and civilian market of the drone industry is generally predicted to surpass that of the defence industry. As the development of drone technology gathers momentum, we are likely to see them used in more maritime applications than ever before.
External vessel inspections
Big names in the maritime industry such as DNV-GL, Lloyds Register & Maersk have all shown strategic intent to revolutionise their operations by embracing drone technology and many maritime operators are now following suit.
All shipowners know that traditional methods of external vessel inspection can be a costly affair. Now that high definition, camera-equipped drones are widely available and affordable, using them for external vessel inspections to assess that the structural condition remains effective, is becoming more common. Identifying substantial corrosion, significant deformation, fractures, damage, or other structural deterioration can be done quickly, easily and cost-effectively using drones.
External inspection typically involves an initial screening of the vessel by the drone. This identifies any areas that require closer inspection, without the need for any access equipment. To do this, the drone is flown over the surface of the vessel using an automatic flight control system controlled by a human pilot. The drone automatically captures survey data, such as video and high resolution images automatically during the flight. The survey data, in addition to payload data, is then transmitted to the system user, who then reviews the information to check for defects on the vessel’s exterior, such as peeling paintwork and dents.
The benefits of drone surveys and inspections are unmatched: acquiring data for external inspections takes a fraction of the time when compared against traditional methods and vessel downtime for inspection is greatly reduced.
The visual inspection of cargo tanks was traditionally performed by workers suspended on ropes to inspect the tank structure. Inspections, which are required on a regular basis, focus on areas of high stress such as; stiffeners; brackets; bracing; webs and stringers and assess the coating condition and check for corrosion and damage within the tank. The sheer size of modern-day vessels however, means that access methods including staging, rafting and climbing are often used by surveyors to access tanks in order to carry out their observations.
Traditional approaches to tank surveys therefore have three main drawbacks: high set-up costs; lengthy inspection times and a high level of personal danger for the worker. For the surveyor, the task typically involves high rope access, working within a confined space, often for extended periods of time. In contrast, drone surveys require no human access to the tank and since no access equipment is required, there are no setup costs and inspections can be completed within a quicker timeframe. For a survey of critical components of a tank, it’s not unusual for shipowners to see a reduction in survey times from three or four days, to completion within one day.
Another key advantage to shipowners, is that by using a drone over conventional staging inside the tank, the risk of damage to the coating from staging is eliminated. Thanks to these benefits, tank surveys using drones are becoming increasingly popular and drone surveys are offered on all large internal tanks, on vessels such as Floating Production, Storage and Offloading (FPSO) units, bulk carriers and tankers.
Bathymetric survey via adapted LIDAR
Accurate and reliable information on the features of water bodies and their shorelines is vital to navigational safety. Bathymetric surveys gather this information, that is then published for use on nautical charts, meaning it’s absolutely vital that this information remains up to date.
Bathymetric Light Detection and Ranging (LIDAR), is used to determine water depth by measuring the time delay between the transmission of a pulse and its return signal. Analysis of these pulses is used to establish water depths and shoreline elevations. Bathymetric LIDAR is also used to acquire data in areas with complex and rugged shorelines, where surface vessels cannot operate efficiently or safely because of rocks, kelp or breaking surf.
It’s not all that long ago that surveyors determined soundings positions by using a three-point sextant, fixed to mapped reference points on shore. The process was labour intensive and time-consuming and whilst the measured depths were accurate, they were often limited in number. Information between the soundings was missing, meaning mariners would often be unaware of features on the bottom and would not have the depth information necessary for safe navigation.
In more recent years, Bathymetric surveys come at a high price. A LIDAR system will typically cost around € 880,000 and that doesn’t include the fixed wing aeroplane or helicopter to fly it. Bathymetric sensors developed for drones are an emerging technology, allowing this type of survey to be carried out flexibly and at a fraction of the cost.
Accurate data concerning bathymetry as well as environmental conditions in shallow waters, can now be acquired using these specialist sensors integrated into drones. To operate effectively in the harsh maritime environment, the technology has been developed to withstand storm force wind and heavy rain, snow and salt spray and as technology advances, so does the flight time available on drones, meaning more area can be covered in a quicker timeframe. Drone technology is therefore revolutionising bathymetric surveys. Faster turnaround times and advanced data is offering more detailed nautical charts, improving global maritime safety.
Flare tip inspections on floating production facilities
Drone surveys typically exist to provide close visual and thermal inspections of high, live or difficult to access structures offshore and there’s nothing more challenging to access than a flare tip, 70 metres above water, on a floating production facility.
The latest drone survey inspection techniques for flare tips, remove the need for a shutdown to inspect the flare and provide the necessary survey data required to reduce, delay or better plan a turnaround. Drone surveys offer reduced costs when compared to traditional and expensive aerial surveys carried out by helicopter or plane. With no shutdown required, maximum efficiency is maintained and thanks to detailed survey data, the performance of the flare system can be assured.
Offshore wind energy sector: An emerging market
The wind energy sector is a growing fast. There are currently more than 270,000 wind turbines operating globally and recent research carried out by market researchers Navigant, has suggested that the cumulative global revenue for wind turbine UAV sales and inspection services is expected to reach nearly $6 billion by 2024. The emerging wind turbine UAV market is being driven by the vast number of blades that need to be inspected for deterioration and for pre-end-of-warranty inspections.
Storm force winds, erosion, lightning strikes and even a build-up of insects can have an impact on turbines. Although they are relatively cheap to repair, the average costs being around 3-5% of the turbine’s price per year, the key to optimum efficiency is knowing where the issue lies.
Surveying wind turbines has always been a challenging job. To inspect the blades, technicians have traditionally had to scale the turbines with the help of ropes and cables and this type of work at height can be very dangerous.
As a maritime company, Martek are used to surveying and inspecting all manner of structures on land and out at sea, anywhere in the world. The company uses a drone fleet that’s specifically designed for turbine blade inspections onshore or offshore, and it outperforms the leading inspection drone.
Martek have surveying wind turbines down to a fine art, with qualified and trained pilots quickly and accurately identifying and assessing faults. Traditional surveying requires turbines to be offline for two hours up to a day, but Martek’s inspection process has reduced that time down to just 45 minutes, which is up to 13 times faster than traditional methods: achieving a minimum of 10 turbines a day.
Following the inspection, the client can access the data through Martek’s secure, cloud-based asset management portal where they can download a detailed PDF report, as well as access raw survey data. Because Martek use trained blade experts with significant experience in assessing and repairing turbine blades, survey findings are always accurate and actionable. Indeed, we can report on up to 25 turbines a day.
The benefits of using drones for blade inspections are wide-ranging. In addition to the obvious benefit of a quicker and more flexible mobilisation, more accurate results are available in a quicker timeframe, and of course there is also a significant reduction in risk. Technicians only need to access the assets that require attention following the survey, eliminating any unnecessary working at height.
Fully autonomous drones: The future of maritime surveying?
As drone technology gathers momentum, leading drone experts are suggesting that fully autonomous drones are the “next big thing” coming our way when it comes to maritime surveying.
When you think about it, it’s not dissimilar to a commercial jet flying on autopilot! Fully autonomous drones are pre-loaded with a 3D model of the ship. This allows the drone to autonomously work its way around the vessel, stopping at point of interest to obtain more detailed video, or image data.
Advancing this further, it wouldn’t be unrealistic to think that the drone will be designed to create its own 3D map of the vessel, before carrying out the survey independently.
If you want to ensure you don’t get left behind in the adoption of this truly transformational technology, please contact the Martek Marine UAS team for a free initial consultation.