Subsea tension loggers

Mooring line tension measurement

Subsea mooring line tension logging (Subsea Tension Loggers). STL 150 shown at fish farm.

Subsea mooring line tension logging (Subsea Tension Loggers). STL 150 shown at fish farm.

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

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.

STL 150

  • Line size: 30-55mm
  • Mass in air: 16kg
  • Weight in water: 11kg
  • Max load: 150kN
  • Max deployment duration: 3 weeks
  • Material: stainless steel and UHMW polyethylene
  • Depth rating: 50m
Subsea Tension Logger

STL150 – 150kN Subsea Tension Logger

STL150 dimensions

STL 800

  • Line size: 52-77mm
  • Mass in air: 44kg
  • Weight in water: 34kg
  • Max load: 800kN
  • Max deployment duration: 3 weeks
  • Material: stainless steel and UHMW polyethylene
  • Depth rating: 50m

STL800 – 800kN Subsea Tension Logger

STL800 dimensions