Foundation piling rotary drilling rig - GIF

[Frank S]

I was not expecting to see that small bit under the larger "wheel". I am wondering how that works. Maybe the big wheel is a guide, there seems to be wear plates on the outside edge. Does the smaller bit extend further whan it gets down in the bore. The water seems very clear the mst ne drilling in rock.

You would be correct. the large diameter guiding ring is holding the drill in the center of a caisson which is resting in the silt

I am wondering if they aren't just getting set uip because the deck of the barge is too clean to have been drilling