Conceptual Design of Seabed drill

Your Task: Find a more economic method of drilling holes in the seabed of a tidal streams than a conventional drilling ship. Your concept should be substantially cheaper than existing methods.
This is a resit, and I have already handed in part 2 of this assigment and handed it in. Please use my report and its feedback at the bottom as well as the audio file feedback from marker to write a good conceptual design report.