By mid September of 1781, Lord Cornwallis understood that his position in Yorktown was precarious. Washington and his French allies had surrounded his army in Yorktown. The Americans were building fortifications and bringing in more munitions and men with each passing day. It would only be a matter of days before they would breach the British defensive earthworks and take the town.
Scouts had reported seeing vessels of the French navy approaching from Chesapeake Bay heading for the York River. With that information General Cornwallis knew that there would be no rescue from the British navy stationed further up the coast around New York city. He was left to defend his position with little hope of reinforcement. If he could hold out long enough, perhaps reinforcements would arrive. He still had some 60 ships anchored in the harbor. Perhaps he could hold on and hope for an early winter, hope for a hurricane to arrive and drive the French navy away so he and his army could live to fight another day. If only...
To that end on September 16, Cornwallis ordered the sinking of some of his vessels near the mouth of the York River. This effectively created a barrier that prevented the larger French galleys from launching an assault onto the Yorktown beach or even out of range of being able to create a barrage on the river side of the town.
The 10 or so large merchant ships were sunk and then piles driven down into the muddy river bottom to prevent the allied fleet from entering. These sunken merchant ships became known as Cornwallis' Sunken Fleet.
On October 10, French ships moved closer. They began firing on the remaining British ships. They were sitting ducks. The French artillerists fired super-heated cannon balls that ignited the splintering wooden ships. One of those ships was the HMS Charon. As the ship began to blaze, it drifted and collided with a transport which it too began to burn. As the Charon burned down to the water line, it drifted towards the Gloucester side of the river and sank. Many years later the in the 1930s, the Charon was located and excavated. One of the cannons found in the debris was mounted in a 1/4 scale replica of the ship on display at the Colonial National Historical Park Museum.
Underwater archaeology of Cornwallis' Sunken Fleet continues today. Many of the ships that were sunk, were well preserved in the muddy waters of the York River, especially on the Gloucester side. A small eddy near where the Victory Monument stands on the Yorktown side of the river created another location where the ebb and flow of the tidal waters deposited silt and mud that protected a few ships that had sunk here.