Parys Mountain dominated the world's copper market during the 1780s, when the mine was the largest in Europe. Its rise severely damaged the mining industry in Cornwall. The copper from the mine was used to sheath the British Admiralty's wooden ships of war, to prevent the growth of seaweed and barnacles and to protect the wood from attack by shipworms. This increased the speed and manoeuvrability of the vessels, and enabled them to remain at sea for longer as there was less need to return to port for maintenance.