woensdag 3 april 2013

St Kilda, Calibrating and finally some nice weather


Yesterday we had to go to St Kilda, in order to wait for the other two participating vessels, because they were a bit too far behind us.
For the blue whiting survey, it is important that all the vessels stay in close proximity to each other, so that we can use the data in the end and realise and the best possible synoptic coverage. In the end we had to chose if we want to continue sailing with 6 knots or go to St Kilda, which was only approximately 1 hour steaming away from us, to let the Irish and Russian come closer to us again. Sailing with 6 miles is not the ideal solution for us though, as we are using a towed body, which will tilt at a certain angle under the water surface if we do not survey at approximately 10 knots. Hence we decided to sail to St Kilda and reschedule the calibration which was planned for after the trip. While the calibration prior to the survey did not work out too well due to harsh conditions, it went very well this time.
The video below shows you how we set up our calibration equipment:

The picture below is an underwater shot of the towed body

 The red circles at the bottom of the towed body are our transducers, the bigger circle is the 38kHz and the smaller one the 120 kHz. On the picture below you can see the towed body hanging along the ship.

 While Eric, Kees, Thomas, Dirk, myself and most of the crew were calibrating, the others went for a small boat trip into a cave, where they could observe a lot of seals and made a few steps onshore, walking up a hill...

After the calibration we went straight back to our "business as usual" - surveying...
Back on track, it wasn't for long until we saw the first schools coming up again. We realised another pure blue whiting trawl yesterday late in the evening.

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