Six on the Seafloor!

Friday, August 17, 2012
PN3A Launch
OOI RSN Primary Node 3A PN3A

OOI RSN Primary Node 3A (PN3A) on the aft deck of the TE SubCom Dependable. Cable segment 6 is on the port sheave (to the right in this photo) and cable segment 7 is on the center sheave (to the left in this photo).

--Photo by Brian Ittig

Plan for OOI RSN Primary Node Installation

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

Another major milestone for the OOI RSN has been achieved with the successful deployment of Primary Node 3A on the northern section of the OOI cabled infrastructure to Axial Seamount. PN3A is the sixth of seven nodes being deployed.

Here's how preparations and deployment proceeded: Early in the morning of Thursday, 16 August, cable segments 6 and 7 were measured and cut for balancing and were then tested. Next step was to splice the cables into Primary Node 3A. These jointing operations were completed at 1900h PDT and successful testing from the shore station in Pacific City, OR, was completed at 2030h PDT. Final preparations for deployment of PN 3A included positioning of the cable segments on the deck of the TE SubCom Dependable. PN3A was then launched from the aft deck, entering the water at 2245h.

The node landed on the seafloor at 0200h PDT on Friday, 17 August. Touchdown at 2600 meters water depth was approximately 43 meters from the target position, which is within our acceptable range. The node was successfully tested from the shore station and tilt parameters were verified to confirm that PN3A was lying flat on the seafloor. As of 0230h PDT, we are recovering the installation line and upon recovery, will commence transit to the location of final node, Primary Node 3B, with an ETA of 0700h PDT, 17 August.

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