Unmanned aerial vehicles are used for class surveys and are now being considered for offshore parcel supply, oil spill response and towline transfer
Flying drones are being introduced by classification societies for surveying ships as a method of accessing areas of vessels that are difficult for surveyors to get to. Several class societies have tested unmanned aerial vehicles (UAVs) as remote inspection devices and have started introducing them into surveying fuel and cargo tanks and cargo holds on bulk carriers and container ships.
The International Association of Classification Societies (IACS) has revised its Guidelines for Use of Remote Inspection Techniques for Surveys and completed its related unified requirements, which are scheduled to take effect in January 2019.
In January 2017, Japanese society ClassNK began a full-scale study of the use of drones in class surveys and conducted various types of verifications by carrying out basic performance experiments including test flights inside ship tanks and cargo holds. It released Guidelines for Use of Drones in Class Surveys in March 2018, which address the sort of use that it had tested.
They combine the technical knowledge of drones accumulated by these efforts – such as the applicable range and procedures for applying them to class surveys – along with considerations for safe operation and the requirements for drone service suppliers.
Using drones for ship surveys does have challenges, such as training surveyors to pilot these remote inspection units in tight spaces and optimising the balance between battery life and weight. ClassNK’s guidelines also take into consideration the possibility that the drone may not function properly due to being in a closed space surrounded by magnetic material, which may interfere with some of the drone’s sensors (which typically rely on GPS and a magnetic compass) which are closely related to flight stability.
Oil spill response
There are also other potential uses for drones in maritime operations. For example, they could be used for surveying and tackling oil pollution. IMarEST’s chairman of a marine pollution group, Matthew Sommerville, summarised the latest developments in pollution control at the International Salvage Union conference in London in March. He explained that UAVs with cameras can be used for counter pollution surveys and to provide advanced imagery of spills.
“They can land on moving platforms and operate in cold and hot conditions,” said Mr Sommerville. He also outlined how balloons that are tethered to vessels and have multiple cameras on board are being used to provide imagery of spillages. “They provide a live feed of oil recovery operations,” he said, “but they are not ahead of a vessel.”
Suppliers of oil spill response equipment have started to develop drones for surveillance of oil pollution and to transfer a device to help burn it off. DESMI is testing a UAV that can do both: it could have a camera for remote imagery of an oil slick or carry an ignition source, said sales manager Mehdi Banisi.
Oil can be burnt as a method of removing it from the sea. For this approach, DESMI’s drone could be flown remotely up to 1 km from a vessel responding to the pollution, Mr Banisi told Marine Electronics & Communications. “By administering an igniter, a person does not need to be in a dangerous position,” he explained.
The same UAV could be used for watching the progress of the oil burn from further away, or provide the camera feed to managers and clients on shore. Autonomous surface vessels can also be used for surveying oil pollution, deploying booms or fire ignition.
Drones could be used for transferring towing lines between tugs and ships. This is an application that tug operator Kotug International is considering. It plans to become the first company to use drone technology to assist in towage operations.
Kotug has applied for a patent to use UAV technology in its tug operations for what it expects will lead to safer and more efficient working conditions. It will test remote-controlled flying devices to connect the towline to an assisted vessel by delivering a messenger line to a predetermined location using object recognition software. The tug’s messenger line is then brought to the assisted ship in a controlled process.
The crew on the assisted ship can heave in the heavy duty mooring line instead of the tug having to sail close to the ship to deliver the heavy mooring line. This will allow the tug to safely sail beside the assisted ship instead of in front of it.
In current operations, a tugboat crew has the challenge of keeping a tug out of danger when delivering a towline to a ship that is arriving into a port. The tug needs to be positioned in front of and close to the assisted vessel in order for deck crew to grab the heaving line by hand.
By doing so, the tug and crew position themselves in the danger zone, close and even under the flared bow of a vessel. Any minor flaw in the operation can result in major injuries to the deck crew and/or damage to the tug and the assisted vessel.
UAVs can also be used for delivering cargo to offshore vessels and platforms. Four Norwegian companies are collaborating to investigate the use of unmanned aerial vehicles or drones to transport cargo between offshore vessels and offshore installations.
Partners in the Safer Logistics from Unmanned Logistics Helicopter research project include offshore support vessel operator Olympic Subsea, Griff Aviation, Norut (the Northern Research Institute) and Stable, which specialises in motion-compensation technology.
Norut is leading the project and has experience in developing autonomous control systems for unmanned air vehicles and of operating them in challenging weather conditions in northern waters. Griff Aviation develops and manufactures drones that have capacity to carry heavy cargo.
The project is drawing on expertise from the research community at the faculty of engineering and technology at the Arctic University of Norway in Narvik, which has extensive experience in automated drone operations.
Stable’s role is to develop a control system so that drones can operate from a moving platform. To begin this, it is developing a stable platform for take-off and landing of the drone. The platform would be placed in a container on a ship’s deck, which would also act as a hangar for the drone. Olympic Subsea is an active development partner in the project, which is supported financially by the Research Council of Norway.
Another drone application has been to remotely inspect offshore facilities. This happened in the North Sea in March when Fletcher Group was contracted by Spirit Energy to provide visual and thermographic surveys of Spirit’s ST-1 platform.
Fletcher used its platform supply vessel, Standard Supplier, to transfer the UAV and two Inspect Hire technicians to survey the platform, which is being prepared for decommissioning.
Spirit Energy needed to confirm there were no gas leaks and it would be safe to plug the associated wells. It decided to confirm this by visual inspection – meaning the inspection either had to be carried out using a handheld camera or by a drone. A Skyeye UAV was used for the project, flown from the dynamic positioning class 2 vessel, which was able to work safely within the 500 m zone.