Copper sheathing<span> is a practice of protecting a under-water hull of a ship or boat from the corrosive effects of salt water and bio fouling through the use of </span>copper<span> plates affixed to the outside of the hull.
It was pioneered and developed by the Royal Navy during the 18th century.
the British were cornered with the us army and french army on land blocking any path of escape and the french navy cutting of their escape routes by sea