7 lives in SeaBed, that is. A couple of days ago when we were on our 6th station, SeaBED disappeared again. We had information that it had completed its mission, both from the acoustic communications and from how much time had elapsed since its beginning, but around the time it was supposed to come back to he open water surface, we started getting pings from it from under the ice, where it shouldn’t have been at that point.
The first time it got stuck under the ice, it was just next to the ship hull on the starboard side. We had used Jeff’s ROV from the aft of the ship – the ROV has a tether of 150 meters – and hooked a line onto SeaBED. This time, it took us over 5 hours of crawling around on the ice with avalanche beacons to locate where it got stuck. It was some 150 meters away from the ship under -luckily- only three meters of ice, and not nine, which was present at the same site.

Drilling a hole at the location where seabed was stuck, about 150 m away from the ship.

It was about 1 PM when we knew SeaBED had wandered off and about 6 when it had been located. We knew it would be pushing up against the ice surface because so the first and most important thing to do was to drill a hole and tie a line to it, so if we could not recover it before the end of the day, we’d have a line on it for the next day. We could tie a line to and pull it out would be the bail hook on its top, however, we didn’t know what orientation it was stuck under the ice and there was no way of knowing where to drill in order to reach the bail hook. A trick we’d used with the first recovery came in handy; we had two cameras available to us that had waterproof housings. We taped one camera at a time onto a long pole, and dipped it in the water through the hole we’d drilled in the ice, to see how the vehicle was sitting. Once the camera was dipped in for 5-6 minutes and an underwater video was taken while someone slowly rotated the pole 360 degrees, it would be brought back up, taken out of the housing, and viewed. Later in the night, Chris and Clay built a real-time camera system that was again mounted on a pole, but it fed live video to a laptop and was instrumental in nailing down where to drill the next set of holes.
The work on trying to reach SeaBED continued all night long, in teams of three. Around 3 in the morning, Jeff, Clay and Till managed to reach the bail hook and tie a line. They then added floats to both to mark its location and to make sure the vehicle floats on the surface if we managed to break away the ice, and then added some weights on the line to make it sink about 25 meters. This was a good idea to avoid potential damage on SeaBED if the only way to get to it the next day would be to have JCR break the ice around it.

This iceberg came to the port side of the ship in a hurry during the rescue operation.

Which, it turned out, would be the way we’d do it. The next morning, there was a brief worry when an iceberg, which had been on the other side of the horizon just a day earlier, came next to us flying by… It slowed down and eventually stopped.
The JCR broke the ice in a controlled manner and swept the slush away. Then Jeff and Till were lowered in the man-basket onto a freely floating chunk of ice to pull the line on SeaBED free.
Through the JCR backing up into the open water, SeaBED broke free of the ice, and the guys in the basket just “walked” it over to where it would be picked up by the ship’s crane and it was home again.

Jeff and Till in the basket trying to pull SeaBED free of the ice.

Once again with special thanks to the JCR crew, SeaBED was back on board.
That evening and the next day was spent inspecting what went wrong. We found the batteries in the Ultra Short Baseline (USBL) tracking system to be nearly dead and the acoustic modem of the vehicle to be receiving, but responding to any pings. Both the batteries and the modem were replaced and SeaBED did a successful mission yesterday. Our team is going through a great learning experience in terms of under-ice search and recovery of auvs.

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2 Comments on 7 Left

  1. Sinan says:

    It’s about time someone tells SeaBed if he keeps behaving this way he will be fired once back home.

  2. Hulya Saydam says:

    The SeaBed does seem to have a mind of its own! It looks like most of the suspense on this trip has been due to SeaBed behaving badly!

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