Kendall,

Fair point about the augers of the period - what about the "little tool just made for the use" as the line runs in one of the versions?

The nine holes made all at once sounds more than a bit far-fetched, but the question asked was could you sink a ship by drilling nine holes in the hull - the answer to that question is yes if you drill the holes to destroy the dowling holding the planks to the frames and ribs of the hull. Lots of variables come into the equation, actual state of the vessel's hull, marine growth, pressure points along the hull, too silly for words, it might be, but impossible, it is not.

As to what can be achieved by a free swimmer on the hull of a ship at sea. I can remember reading a book about the China Clippers and some of the jury rigged repairs they managed to carry-out to hulls and rudders were quite amazing, in most cases way could not be taken off the ship as they had to maintain some sort of heading into sea.