The circular prospection
That morning, we briefly listed the most important methods of visual subaqueous prospection: in line, in grid, in circle...
but also some non visual methods: magnetometry, sonar... As regards that afternoon diving, new lines and other items were laid out on a second excavation site at a depth of 10 metres.
Pulling on an end of a line while fixing the other end with leads, the divers decribed a circle with a known diameter and without deriving. The divers are this way turning
around a second line which is fixed at the bottom. Everytime an item was found out, we measured its position from the second line. This method is called: circular prospection.
Four lines were also placed to allow two teams to work at the same time. We knew in advance that we would have to find out ten items.
We slowly moved forward and for each item found out we wrote the graduation on the line and course compared to a diameter of the circle. The tone of that last diving was very relaxed:
some teams buried the items to "help" the next teams, some lucky divers were more interested in watching a murray eel than in finding the items out.
Finally the teams that have finished their work came back to see us in skin diving, and it was the opportunity to take some underwater group photos.
Trying the engine
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To continue with the prospection topic, Arnaud firstly showed us the board which we towed a diver with, using a boot fixed on a zodiac and which was supposed to be quickly removeable in case of trouble. Then he showed and let us try an engine, which allowed visual prospection on a longer distance, or in a shorter time. |
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For the last day, the tone was very relaxed!
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After the last diving, we forgot to do the debriefing and our drawing. Instead of that, we tried the engine, took some group photos, tried a little plunging,
and finally listened to some unofficial truths about the job of archeologist (only available from SEAS).
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