Mooring Line Integrity Monitoring

Courtesy of APL Norway AS

Scanmatic uses its expertise within underwater instrumentation, data acquisition, communication and system integration in the delivery of systems for monitoring the integrity of mooring lines lines and other underwater infrastructure.

Scanmatic’s commitment in this field started with a challenge from one of our customers to develop a more robust inclinometer solution than was available on the market. An inclinometer is mounted on the mooring line to measure its angle and detect a line break. In particular, the cables that intersect the moving area between the FPSO / loading buoy and the inclinometer were prone to wear and tear. Scanmatic developed a new system with integrated cable protection that significantly reduces the probability of cable failure.

In addition to sensors for monitoring tension and angles, a delivery of a Scanmatic mooring line monitoring system includes subsea cables, cable protection, solutions for routing cables through e.g. pipes using special flanges, subsea connectors that can be replaced by divers or ROVs, junction boxes and data acquisition cabinets, signal conversion and data integration solutions, and topside presentation and alarm management solutions.

An example of a delivery is presented here: Mooring Line Monitoring in the Gulf of Mexico.

Scanmatic has also developed a solution for detecting mooring line failure which do not require having a cable traversing the dynamic area, but which use proximity sensors to read a coded plate mounted on the mooring line link to determine its angle. Read more about this solution here: Mooring Line Monitoring – Proximity Switch.

Scanmatic’s latest solution has received a lot of attention. It uses small sensors that measure angle, depth or motion, and transmits this information wirelessly using hydroacoustics (sound in water). The solution is very cost-effective compared to existing wireless solutions and can be retrofitted to existing installations in simpler ways. Scanmatic considers this solution a “game changer” in this field. Read more about the solution here: Acoustic Subsea Monitoring.

The wireless solution was retrofitted in 2019 at an FPSO in the North Sea. See here for more information on that delivery: Retrofit MLM results from Teekay’s Petrojarl Knarr