On March 27, 1794, Congress passed the “Act to provide a Naval Armament” which authorized President George Washington to create the new United States Navy. Each of the six frigates that made up the new U.S. Navy was to be “copper bottomed”, i.e., covered below the waterline in thousands of pieces of overlapping copper sheets. This prevented boring mollusks from destroying the wood and allowed for greater ease in cleaning marine growth from the ships’ bottoms. In a letter dated April 21, 1794, Joshua Humphreys, a shipwright from Philadelphia who was the principle designer of the original six frigates, listed “An estimate of the quantity of Timber Plank &c for a frigate…” the size of Constitution, including the copper needed – “12000 feet of sheet copper for bottom”.
The video below, courtesy of The River Project, shows how Teredo navalis (ship worms) burrow through wood.
On July 2, 1797, just months before Constitution was to be launched in Boston Harbor, the Secretary of War James McHenry wrote to George Claghorne, Constitution’s Naval Constructor:
It being of importance to the United States that the Frigate Constitution should be coppered on the Stocks before she is Launched into the Water – you will therefore be pleased to cause the said Ship to be coppered as high as light water mark as soon as the Bottom is prepared, as it will prevent heaving down afterwards and a Consequent heavy expense… [Secretary of War, James McHenry, to George Claghorne, 27 July 1797. Naval Documents…Barbary Wars, Volume 1, 205.]
Paul Revere, of “Midnight Ride” fame in the American Revolution, was a 60-year old silversmith, merchant, and foundry man in the 1790s. He contracted with Henry Jackson, the Boston Naval Agent in charge of obtaining materials for the building of USS Constitution, to provide the copper and brass fittings for the ship “…as cheap as anyone and as well.” Revere’s foundry drew down the English-made copper bolts used to fasten Constitution. The foundry also provided a 242-pound bell and other fittings between 1794 and 1798.
In early 1803, USS Constitution was readied by Commodore Edward Preble for a lengthy voyage to and deployment in the Mediterranean Sea against the North African Barbary Corsairs. The original copper sheathing was worn out and new sheathing was needed. Enter Paul Revere again and by the 1803 re-fit of Constitution, he had a copper rolling mill in operation in Canton, Mass. and was able to provide the thousands of sheets of copper needed for the ship.
While copper prevented mollusks from boring into the wood and destroying the lower hull of a sailing vessel, it did not completely prevent marine growth from fouling the ship. In the summer of 1810, Secretary of the Navy Paul Hamilton, disappointed with Constitution’s sluggish sailing, instructed Captain Isaac Hull to sail up the Delaware River where the fresh water would kill the salt water shellfish. In August, Hull conveyed to Hamilton the following news:
Since the ships arrival in fresh water the mussels on her bottom have all opened, and the inside entirely washed out with the run of the tide, and they are fast falling off‑‑ The oysters I find do not feel the effect of the fresh Water so sensibly, yet I have great hopes that a few days more will cause them to open and fall off in the same manner as the mussels. [Isaac Hull to Paul Hamilton, 15 Aug 1810. M125, Captains’ Letters to the Secretary of the Navy, 1805-61; 1866-85, In National Archives]
Just three days later, Hull reported that divers sent down noted that the copper was rough and missing in places and that some of the copper nails were coming loose. They attempted to patch bare spots in the sheathing.
Over the years Constitution has been recoppered at least 12 times. Throughout the 19th century, Constitution’s copper sheathing was periodically replaced and, beginning with the 1833 docking of the ship in the Charlestown Navy Yard, souvenirs were fashioned from the copper sheathing (a miniature copper kettle was made from copper removed in the mid 19th century).
In the 20th century, the sheathing was replaced several times.
In the 1927-1931 extensive restoration of Constitution the final restoration report tallied the following about the copper:
Ship has been copper sheathed from keel to 23’ 6” aft and to a height of 21’ 0” forward – 3,400 sheets of copper, 14”x 48”, in various weights; 28-oz. between keel and shoe, 26-oz. at turn of bilge and at water line; remainder 22-oz., all of which is secured to wood planking by 1 1/8” and 1 ¼” copper sheathing nails. Approximately 12.5 tons of sheathing copper, 1600 pounds [copper] sheathing nails, 38.4 tons new copper fastening[s] used; 4 tons old copper fastening [reused?], 8 tons old copper left in ship; a total of 63.7 tons of copper now in the ship. [Commandant, U.S. Navy Yard, Boston, “U.S. Frigate CONSTITUTION (IX21) – Research Memorandum”, 1931, 60.]
USS Constitution‘s copper sheathing will again be replaced during the 2015-2017 restoration. This will be the fourth time in the past century that all of the ship’s copper is replaced. Souvenirs made from copper removed from USS Constitution are available at the USS Constitution Museum Store: Jewelry and Limited Edition Medallion
– M. M. Desy & K. Monea
USS Constitution Museum