I-COT – Robotic In-Service Cargo Oil Tank Inspection

At Geo Oceans, we specialise in delivering innovative robotic inspection solutions for the offshore energy industry. Our I-COT (In-Service Cargo Oil Tank) system is a next-generation ROV-based technology designed for non-intrusive inspection (NII) of FPSOs, tankers, and marine vessels. This advanced service provides comprehensive condition mapping of cargo oil tanks (COTs) by accessing them from adjacent water ballast tanks (WBTs)—eliminating the need for manned entry and minimising operational disruption.

What is I-COT?

Unlike single-purpose tools, I-COT is a versatile delivery platform for a suite of unmanned and robotic advanced NDT methods, customised to meet the specific inspection requirements of each tank.

By integrating technologies such as Multiplexer UTM probes, I-COT enables accurate wall thickness measurements and corrosion mapping from locations traditionally inaccessible during internal inspections.

In a project on an FPSO in the Gulf of Mexico, Geo Oceans successfully deployed I-COT to assess the condition of COT/WBT shared boundaries. Using the Multiplexer UTM probe, we captured high-resolution data on structural integrity without entering the COT. This approach also allowed us to:

Inspect areas typically hidden under sediment.
Map corrosion on the deck from within the WBT.
Reduce inspection time and associated costs.
Enhance safety by avoiding confined space entry.

Benefits of I-COT

Non-intrusive inspection (NII): Gain actionable insights without internal tank entry.
Advanced NDT capabilities: Integrates multiple inspection techniques into one deployment.
Operational efficiency: Minimise downtime while meeting class and regulatory requirements.
Comprehensive coverage: Access complex geometries, horizontal and vertical boundaries, and high-risk areas such as hoppers and decks.
Risk-based inspection planning: Focus on critical areas using data-driven methodologies.

Key Applications

FPSO Cargo Oil Tank Inspection: Map shared boundaries between WBTs and COTs to determine structural integrity.
Water Ballast Tank Inspection: Capture condition data from easily accessible areas to gain insights into harder-to-reach COT regions.
Deck and Sediment-Covered Area Assessment: Identify corrosion in high-risk zones traditionally hidden from view.
Risk-Based Inspection Planning: Use I-COT data to focus maintenance and minimise unnecessary tank entry.

Technology Deep Dive

At the core of Geo Oceans’ I-COT capability is the purpose-designed I‑COT ROV system, developed in collaboration with Sonomatic and a client’s global robotics team.

Engineered specifically for in‑service cargo oil tank inspections, the platform translates I-COT methodology into a robust, repeatable robotic deployment.

Real-time inspection data with navigation aids to ensure complete coverage.
Sealed LARS deployment for safe, in-service operations without tank entry.
Configurable probe positioning for top, bottom, or side inspections.
Magnetic wheels for stable scanning on vertical and horizontal steel surfaces.
Intuitive control station with live camera feeds for confident remote operation.

AUAV Drone Technology

AUAV provides advanced robotic drone solutions to support FPSO inspection, integrity, and survey activities, working closely with Geo Oceans and Sonomatic to deliver fully integrated inspection campaigns. By combining aerial robotics, remote sensing, and NDT expertise, AUAV technologies help reduce confined‑space risk,

minimise production downtime, and improve asset reliability—without the need for manned entry. These drone-based systems are deployed alongside crawler and ROV inspections to enhance situational awareness, inspection coverage, and data confidence across the FPSO lifecycle.

Tethered UT drone systems providing persistent power, stable operation, and high‑quality data capture in enclosed environments.
Third‑person visual support to aid robotic navigation, situational awareness, and inspection planning.
Confined-space risk reduction by eliminating the need for personnel entry into hazardous cargo tanks.
Integrated inspection delivery alongside robotic crawlers and ROV platforms for complete condition assessment.
Minimal operational disruption, supporting inspections during in‑service conditions.

SIMS Digital Twin Software

Sonomatic has been at the forefront of providing digital twin capability through our SIMS packages. The digital twin is a single entry point for access to all inspection

data, whether it is reference data, photos, reports, inspection planning, individual scans, or post-processed data analysis. The key features include:

Host Any Type of Data
Host the Latest Inspection Results (Raw Waveform, Wall Thickness Data, etc.)
Host Historical Data Analysis to Demonstrate for Trend Analysis
Access to Historical Reports, Images and Photos etc.
Access to Previous Inspection Data and Information

Integrated I-COT Inspection Approach

I-COT inspections can combine robotic crawlers, ROVs, and tethered drones to assess tank condition without personnel entry. Robotic crawlers equipped with Phased Array UT can inspect targeted areas, while tethered drones provide third‑person visual support for navigation and documentation. In parallel, the I‑COT tool can be deployed from adjacent Water Ballast Tanks to collect wall thickness data, with minimum readings analysed using established Non‑Intrusive Inspection (NII) principles to support post‑inspection assessment and risk‑based maintenance planning.

Project Examples

I-COT was engineered to address common challenges in FPSO and marine vessel inspection, including limited structural information, complex orientations, narrow hatchways, and obstructions. Through collaborative development with our sister

company Sonomatic and global partners, we have created a system capable of cost-effective, high-accuracy inspection under demanding conditions. Explore project examples below, and read about our class sign off for the world’s first entirely robotic FPSO Cargo Oil Tank Special Survey, here.