Sections of the hull of H.M.S. Terpsichore, showing effect of the torpedo explosion at Chatham, 1865. Official drawings ...by Mr. P. Thornton, Master Shipwright of Chatham Dockyard, showing the exact amount of damage that was inflicted upon the hull of the old 18-gun frigate Terpsichore by the explosion of the two 75-pounders [during] the very striking experiments with Mr. Beardslees submarine torpedoes, or explosive shells...in the River Medway. No. 3 shows the relative positions of the ship, the torpedo, and the boat from which it was fired by an electric wire: the figure a representing the place where the boat lay when the torpedo was lowered from its side; while the figure b shows the place to which the boat had been removed before the signal of firing the torpedo was given...No. 1 shows the general longitudinal lines of the ship, with the hole made by the explosion of the torpedo...An enlarged view of a portion of the outside planking around this hole is also given. No. 2 presents a cross section of the vessel, showing very minutely how her timbers were shivered. In the parts marked a, the knees are seen as broken through the throat - viz., two on the starboard and four on the port side. From "Illustrated London News", 1865.