Although I don't have the coords, I do have a map screenprint, which I think would be as precise. You can see my arrow on the map just south of the Southeast Workshop "Eastspark Vehicle Workshop" / Graveyard.
If you still can't find the spot from that arrow, consult the image from above that shows the missing tile.
If you still can't the spot you can look at the east, south, & west views from underwater and find it that way.
Let me know if you have issues finding it after this