New Segment 7

Wednesday, August 15, 2012
Cable Installation Segments
Plan for OOI RSN Primary Node Installation

Plan for OOI RSN Primary Node Installation. Node drawings courtesy of L-3 MariPro.

Steady progress continues to be made on the installation of the northern section of the OOI RSN cabled infrastructure to Axial Seamount.

The end of cable segment 6 was successfully retrieved by grapnel operations and approximately 10.2km of segment 6 was recovered and repositioned along the final cable route. The end of cable segment 6 was deployed to a buoy,

Operations have also included recovering 27.1 km of cable segment 7, which was installed in summer 2011. A post-installation ROV survey revealed that part of this cable segment had been laid through a new and active hydrothermal vent field on the flank of Axial volcano. Because of the potential for cable damage from the extremely high temperatures in this vent field, the decision was made to recover the 2011-laid cable and install a new segment 7 as part of the primary node installation operations now underway. The TE SubCom Dependable, the vessel being used to install the primary nodes, is also the commercial vessel that was used to lay the primary cable segments in summer 2011.

Segment 7 connects Primary Nodes 3A and 3B and is being installed towards Primary Node 3A, from west to east. As of 0300h PDT, we have completed approximately 50% of the new cable installation along a route that avoids the active hydrothermal vent field.

Upon completion of the cable segment 7 installation, the segment 6 buoy will be recovered and Primary Node 3A will be spliced into the system.

For video taken at Axial Volcano during the VISIONS '11 cruise in August 2011, visit the expedition website here.

-- Brian Ittig, OOI RSN Marine Operations Manager, University of Washington, onboard the TE SubCom Dependable