Museum opened on 8 April 1976, and Commander Martin dedicated a tract of land as "Constitution Grove" one month later, located at the Naval Surface Warfare Center in Indiana. The now supply the majority of the white oak required for repair work. On 10 July, Constitution led the parade of tall ships up Boston Harbor for Operation Sail, firing her guns at one-minute intervals for the first time in approximately 100 years. On 11 July, she rendered a 21-gun salute to Her Majesty's Yacht Britannia, as Queen Elizabeth II and Prince Philip arrived for a state visit. The royal couple were piped aboard and privately toured the ship for approximately 30 minutes with Commander Martin and Secretary of the Navy J. William Middendorf. Upon their departure, the crew of Constitution rendered three cheers for the Queen. Over 900,000 visitors toured "Old Ironsides" that year. 1995 reconstruction Constitution entered dry dock in 1992 for an inspection and minor repair period that turned out to be her most comprehensive structural restoration and repair since she was launched in 1797. Multiple refittings over the 200 years of her career had removed most of her original construction components and design, as her mission changed from a fighting warship to a training ship and eventually to a receiving ship. In 1993, the Naval History & Heritage Command Detachment Boston reviewed Humphreys' original plans and identified five main structural components that were required to prevent hogging of the hull, as Constitution had of hog at that point. Using a 1:16 scale model of the ship, they were able to determine that restoring the original components would result in a 10% increase in hull stiffness. Three hundred scans were completed on her timbers using radiography to find any hidden problems otherwise undetectable from the outside—technology that was unavailable during previous reconstructions. The repair crew used sound-wave testing, aided by the United States Forest Service's Forest Products Laboratory, to determine the condition of the remaining timbers that might have been rotting from the inside. The of hog was removed from her keel by allowing the ship to settle naturally while in dry dock. The most difficult task was the procurement of timber in the quantity and sizes needed, as was the case during her 1920s restoration as well. The city of Charleston, South Carolina, donated live-oak trees that had been felled by Hurricane Hugo in 1989, and the