Vertech Group were recently contracted to carry out an inspection of the 6 Centre Cargo Oil Tank (6CCOT) as part of an FPSO special survey, under Lloyd’s Register supervision.
The inspection was carried out across three campaigns. During the first two campaigns, challenges were encountered accessing certain areas of the tank.
Close Visual Inspection (CVI) was required on all deck longitudinal connections to both transverse bulkheads, as well as every transverse web frame connection to both longitudinal bulkheads. With the tank temperature being in the 35-45 Celsius range and the humidity close to 90%, gaining access to these areas was risky.
With Vertech’s recent addition of the Flyability Elios 2 UAV, it was decided to execute the remainder of the CVI requirements using the drone. The first couple of days on board was spent setting up for the inspection. In-depth flight plans were created, a risk register was compiled, permits were obtained, and suitable landing platforms were set up within the 6CCOT.
The first couple of flights were reconnaissance flights to ensure everything was functional, there were no hazards that would potentially damage the drone, and that flight paths were clear. The UAV performed far better than anticipated. Sensors located on the drone lock onto the surrounding structure, allowing it to automatically compensate for the heave of the vessel. These sensors also prevented the drone from coming into contact with the target structure, which gave the team confidence when flying in a confined space. Due to improved lighting, we were also able to provide depth and dimensionality to the object being inspected.
Using the UAV, Vertech carried out all of the visual inspection requirements in 6CCOT. The Lloyd’s surveyor was present for part of the trip. He witnessed the Elios 2 in action and asked us to perform several inspections in the tank. Several of the core crew, including the Offshore Installation Manager and Production Supervisor, also entered the tank to see the UAV at work.
We received very positive feedback on the performance and usability of the UAV, not only for tank inspections but the other inspections as well. The UAV significantly reduced the time required to complete the inspection, it was more cost-effective and also massively reduced the risk to technicians when it came to Confined Space Entry (CSE).
Going forward, the possibilities and opportunities the Elios 2 can provide are very promising. With Lloyd’s approval in place, I see this piece of kit as an invaluable addition to any inspection scope. Watch this space…By Matt Bain – Senior Hull Tank Inspector