Copper Sheathing - Widespread Implementation

Widespread Implementation

With the American war in full swing, the Royal Navy set about coppering the bottoms of the entire fleet. This would not have happened but for the declarations of war from France (1778), Spain (1779) and the Netherlands (1780): Britain had to face her three greatest rivals, and coppering allowed the navy to stay at sea for much longer without the need for cleaning and repairs to the underwater hull, making it a very attractive, if expensive, proposition.

Fortunately the Parys Mountain copper mine on Anglesey, Wales had recently begun large-scale production that had glutted the British market with cheap copper; however the 14 tons of metal required to copper a 74-gun third-rate ship of the line still cost £1500, compared to £262 for wood. The benefits of increased speed and time at sea were deemed by the Admiralty to justify the costs involved, and in May 1779 all ships up to and including 32 guns were ordered to be coppered when next they entered dry dock. In July this order was expanded to include ships of 44 guns and fewer.

It was then decided that the entire fleet should be coppered, due to the difficulties in maintaining a mixed fleet of coppered and non-coppered ships. 82 ships of the line had been coppered by 1781, along with 14 50-gun ships, 115 frigates, and 182 unrated vessels. By the time the war ended in 1783 problems with the hull bolts were once more becoming apparent.

Finally a suitable alloy for the hull bolts was found, that of copper and zinc. At great cost, the Admiralty decided in 1786 to go ahead with the re-bolting of every ship in the navy, thus finally eliminating the bolt corrosion problem. This process lasted several years, after which no significant changes to the coppering system were required, and copper plating remained the standard method of protecting a ship's underwater hull until the advent of modern anti-fouling paint.