Autonomous Drone-based Surveys of Ships in Operation

Research Review 2018

The vision of ADRASSO is to develop an intelligent, autonomous drone for ship inspections. The drone will fly, by itself, into a cargo or ballast tank, track its location, and use artificial intelligence to spot rust, cracks or poor coating condition, as well as measuring steel thickness, comparing with historical data to document the development of rust and cracks. This would improve safety, inspection quality, and environmental impact.

Ship safety: Today this is ensured by inspections and is regulated by the International Maritime Organisation (IMO) and other bodies. Classification societies like DNV GL carry out the inspections in accordance with IMO regulations. The ship safety depends to a large extent on the inspection thoroughness of the Class society and the individual inspector.

Personnel safety: Today, human inspectors enter ballast tanks and inspect them visually. This is risky. To come close enough for visual inspection in 20-30 meter- high tanks, the inspector uses scaffolding, rafting in a tank filled with seawater, or rope climbing. Falling accidents are commonplace. Oxygen shortage is another risk, and further, rafting accidents occur inside the tank when the ship is rolling. In hot climates, such as Dubai, over-heating poses another risk, with temperatures inside the tanks sometimes exceeding 50 degrees.

Inspection costs: The total cost of a single surveying can exceed 1 000 000 USD once vessel preparation, use of yard’s facilities, cleaning, ventilation, and provision of access arrangements are taken into account. In addition, owners experience significant lost opportunity costs while the ship is inoperable. Some examples to illustrate the cost: scaffolding erection, 200 000 USD; 1-2 days in dock, 100 000 USD for an oil tanker on good rates; emptying tanks for methane gas and substitute with inert gases and oxygen, 100 000 USD for LNG/LPG ships. Additionally, the manning costs for the inspection itself, which often including long travels.

Environmental costs: Releasing water from oil tanks after a rafting-based inspection is a source of pollution. In Northern Europe, this inspection method is therefore not allowed. Furthermore, the tanks must be emptied in open sea away from ports and shore, so the ship would have to leave port - yet another 2-3 days out of operation. In practice, rafting is therefore applicable only in voyage surveys.

The ADRASSO project is targeting all these challenges and will provide the maritime industry with the following benefits:

  • Improving personnel safety by reducing the number of tank visits
  • Reducing inspection cost by removing the need for erecting scaffolding, water filling for rafting, the need for oxygen and inerting the tank, and providing more streamlined processing and reporting of findings
  • Improving efficiency due to reduced inspection time, quicker reporting and faster decision-making.
  • Reducing environmental footprint with no need for rafting and hence the filling and emptying of polluted water.
  • Improving inspection transparency because the drone can track where it is and what it has done, and this track can be logged. Therefore, the inspection scope can be documented in terms of areas inspected, and likewise, the number and location of thickness measurements. 
ADRASSO is supported by the Research Council of Norway, and is led by DNV GL in cooperation with Scout Drone Inspection, Jotun, Norsk Elektro Optikk (NEO), Idletechs and NTNU.