USS Constitution, known as "Old Ironsides," is a wooden-hulled, three-masted frigate of the United States Navy. Named after the United States Constitution, she is the oldest commissioned ship afloat in the world, and is still in service in the US Navy. The Constitution was one of the six original frigates authorized for construction by the Naval Act of 1794 and was launched in 1797. Joshua Humphreys designed them to be the Navy's capital ships and so Constitution and her sisters were larger and more heavily armed than the standard frigates of the period. On August 19, 1810, she met the frigate HMS Guerriere off the coast of Nova Scotia. The British frigate opened fire upon entering range of Constitution. Captain Hull held his ship's guns in check until the two warships were a mere 25 yards apart, at which point he ordered a full broadside. Over the course of the engagement, the ships collided three times but musket fire from the Marine complements on both Guerriere and Constitution prevented boarding parties from being sent. During the third and final collision, Guerriere 's bowsprit became entangled in Constitution 's rigging. When the two ships pulled apart, the force of extracting the bowsprit sent shockwaves through Guerriere 's rigging. Her foremast soon collapsed and it took the mainmast down with it shortly afterword. At the conclusion of the engagement Guerriere was a dis-masted hulk, so badly damaged that she was not worth towing to port. Hull had used his heavier broadsides and his ship's superior sailing ability, while the British, to their astonishment, saw that their shot seemed to rebound harmlessly off Constitution's strong live oak hull—giving her the nickname "Old Ironsides".