Thanks to a fibre-optic link to the surface, a depressor (clump weight) decouples the vessel and the submersible, and a special system for managing the tether compensates for the surface vessel’s lack of dynamic positioning.

This device comprises:

  • A fine tether called the “vehicle tether” deployed from the vehicle via a constant-tension TMS,
  • A towing tether deployed from the clump weight,
  • A float connecting these two tethers.


The dynamic management of the two-part tether compensates for the movements of the support vessel in a radius of 300 m around the device’s position.