Good news that the skiff was on target. The direction the line bends between the camera and weight might be a clue of the current direction, or any excess line attached to the weight. If that is evident.
There is obvious displacement of the line in many of the photos, as in Frame 401 below, but in others the line is slack as in Frame 435.
Ron Bernier, who was handling the line, says, "The camera did not remain perpendicular and at times the angle may have been 20˚ as the boat was positioning. At one point I pulled it up tens of meters before lowering it back to bottom in an effort to get it closer to being under the skiff. I was so focused on ‘feeling’ the bottom that I am not clear on how the skiff position matched up."
It's not clear whether the displacement of the line was due to current or the movement of the skiff. I wouldn't expect the current to change dramatically minute to minute so I suspect that the strain we see on the line was caused by the fact that the skiff was moving.