In examining the earlier reports of the Secretary of the Navy, many things of considerable historical interest in naval construction have been encountered. Notable among these are the communications of Lieut. W. W. Hunter, U. S. N., following the trial of the wooden steamer Union, in 1843, which was fitted, on his design, with horizontal paddle wheels, submerged at the after part of the ship. This vessel made a trial cruise from Washington to Boston and return; and while in Hampton Roads developed a speed of to knots an hour.
On the return from this cruise, Hunter addressed a letter to the Secretary of the Navy, A. K. Upshur (who was loud in his praise of this vessel), recommend- 1ng the construction of vessels with similar means of propulsion, but built of iron. He...set forth ably and with great lucidity the advantages of iron as a material of construction, and appends to his letter a recommendation for the use of an iron shield deck above the level of water-line amidships, and sloping to beneath it at the sides.