Dateline: Nikumaroro, 17 July 2012
We have a saying at TIGHAR, all too often used – “Adventure is what happens when things go wrong.” There were some adventures today.
The AUV was hung up underwater for four hours last night. It freed itself and continued the mission but got stuck again as it was ascending for recovery at a depth of 722 meters (2,368 feet), west of the island’s NW tip.
Leave the AUV where it is for now, go search for the target identified yesterday with the ROV, and come back this evening to recover the AUV with the ROV if it hasn’t freed itself by then.
Risks to Option 1:
• The good navigation beacon is on the AUV so we would have to do the target search using the marginal navigation beacon.
• If the AUV frees itself during the day and comes to the surface and they lose radio contact with it, we could end up searching for it visually. Not good.
Immediately go after the AUV with the ROV.
Risks to Option 2:
• The ROV will have to use the marginal navigation beacon – but that is also true of Option 1.
• The 722 meter (2,368 feet) depth is near maximum for the ROV.
18:30Z (08:30 KOK)
We made the decision to go for Option 2 and began preparing the ROV for the rescue mission. We’ll lose the morning for search operations but we’ll run the ROV into the night if need be.
21:30Z (11:30 KOK)
The rescue mission was successful – but it was a real cliff-hanger. Operating literally at the end of our tether, we searched for over an hour in nightmare terrain: a vertical cliff face pockmarked with caves and covered with fern-like marine growth. We finally came across the AUV wedged cross-wise (parallel parked) in a narrow cave.
Wolfgang flew in and used the claw to gently grab a handle near the stern of the fish. He then pulled the AUV out ofthe cave and well clear of the cliff face before releasing it to float to the surface. Once the ROV and AUV are recovered aboard, we’ll reposition and try again to find yesterday’s promising sonar target.
The above directly from Ric in an email. When he called, he was about to take a small party ashore, because the recovery of the AUV and the maneuverings required had strained something in the ship’s power train which would take some hours to fix. By nightfall they expect to have ROV in the water again and will operate through the night if necessary.