Mooring line tension measurement

DSA’s Subsea Tension Logger (STLs) measure and record the tension in lines or ropes in exposed marine or subsea environments. The STL can be used to measure tensions in:

Synthetic mooring lines
Umbilicals
Hawsers
Wire rope
Flexible risers or pipes
Armoured cable

Subsea tension logger deployment at a fish farm

Applications

Applications for the STL include:

Offshore platform moorings
Ship moorings and towlines
Aquaculture moorings
Umbilical loading
Oceanographic or navigation aid moorings
Marine renewable energy platform moorings

How it works

The STL uses a battery powered data logger and a strain gauge sensor to measure and record tensions. The STL consists of a stainless steel tensionmeter and a waterproof electronics housing.

Key benefits

Does not require disconnection of the mooring line to install
Can be calibrated for different line sizes
Configurable data acquisition
Can be custom built for different applications
Easily installed by divers in subsea applications

Installation description

Installation can be accomplished in a few simple steps. First, the anti−chafe protective sleeve is attached to the mooring line. Next, the locking collar is disengaged and opened. The STL is then oriented to the mooring line and then the locking collar is re−engaged to secure the unit in place. The handles are used to securely tighten the locking collar on to the line in order to ensure reliable and accurate tension readings.

Data recovery

Once the deployment is complete, data is easily extracted by removing the housing end cap, unplugging the power supply, and removing the memory card. The time stamped tension data is stored in text files on the memory card. The ASCII text files can be easily downloaded onto a computer and viewed in Excel, Matlab, or any similar program.