Enhancing precision in underwater infrastructure projects with Exail Gaps USBL system

A major European infrastructure project is reshaping urban transportation in a bustling metropolitan area by expanding its metro network. This ambitious development aims to improve the city's transit efficiency and boost regional connectivity, significantly reducing commuter travel times. A centerpiece of the construction is a new railway tunnel that runs beneath a river, presenting unique engineering challenges, particularly in underwater sections.

To manage these complex underwater operations, Scanmudring, a leader in subsea engineering, was brought on board. The company leveraged advanced technology to ensure precision and safety in their operations. A key component of their strategy was the deployment of the Exail Gaps M5 USBL system. This system played a crucial role in accurately positioning their largest subsea excavator, the remotely operated 40Te Scanmachine, and in tracking divers and referencing underwater structures.

Navigating challenges below the surface

The underwater excavation works presented numerous challenges. The environment was characterized by steel walls, confined spaces, high turbidity freshwater with zero visibility, and many unknown variables. These conditions made acoustic positioning and underwater operations particularly difficult. To overcome these obstacles, Scanmudring needed an advanced positioning system capable of maintaining high accuracy and dependability under demanding conditions.

Innovative USBL solutions for precision underwater operation

For this purpose, Scanmudring chose to deploy the Exail Gaps M5 USBL system to accurately position their largest subsea excavator, the remotely operated 40Te Scanmachine. Specifically tailored for underwater positioning at depths of down to 1000 meters, the Gaps M5 system demonstrates exceptional efficiency in shallow water and horizontal conditions, making it suitable for any tracking operations.

Stian Aanensen, Tender Manager at Scanmudring, highlighted the importance of selecting this system:

"The project presents a very challenging environment for acoustic positioning and underwater excavations. The Gaps M5 system provided an easily deployable, readily calibrated, and high-performance solution. Despite uncertainties regarding performance in such conditions, the Gaps M5’s capabilities significantly enhanced the likelihood of success. In addition, Exail provided a technically and commercially viable solution prior to the project, making it the preferred option."

Streamlined integration for seamless execution

To ensure optimal performance, the Gaps M5 USBL was mounted on a pole secured to a beam that runs the length of the construction pit. This configuration ensures direct acoustic visibility for consistent, accurate positioning throughout the project. Precise mapping of the beam’s position by a surveyor allowed the Gaps system to account for orientation (heading, roll, and pitch) and ensure exact placement on the beam. The system’s compact and lightweight design, coupled with its embedded FOG AHRS for self-calibration, simplified installation and made it highly user-friendly. As Aanensen noted,

"Gaps was much easier and more user-friendly to configure than previously used systems, even for personnel not being experts in positioning systems."

This ease of use translated into a swift setup process, allowing the team to begin operations without delay.

Empowering teams with Exail expert support

The support provided by Exail was instrumental during the mobilization phase. On-site specialists from Exail offered training and insight, enhancing Scanmudring’s team’s capability to operate the Gaps system effectively. 

"We were very satisfied with the on-site support from Exail. It built credibility with our end client and ensured our crew was well-prepared for using the system," says Aanensen.

Achieving precision in a complex environment

The collaboration between Scanmudring’s advanced excavation technology and the Exail Gaps USBL system delivered significant outcomes: 

• Accurate positioning: The Gaps system enabled precise control of the Scanmachine, ensuring accurate underwater excavation despite challenging conditions.
• Operational efficiency: The ease of use and quick setup of the Gaps system allowed the project to proceed without delays, improving overall efficiency.
• Enhanced safety: Real-time tracking of divers and equipment reduced the risk of accidents, ensuring a safer work environment.
• Client confidence: The support from Exail and the demonstrated reliability of the Gaps system-built trust with the end client, reinforcing the project's credibility.

Driving progress: setting new standards in underwater infrastructure

The success of Scanmudring’s excavation operations, enhanced by the precision of the Exail Gaps USBL system, underscores the critical role of advanced technology in tackling complex underwater construction. This project, aimed at transforming urban transit, has set a new benchmark in underwater infrastructure development, laying a foundation for future projects that demand precision and reliability in similarly challenging environments.