U.S. Gunboat Cairo. Unfortunately, records are not in accord on the U.S.S. Cairo. One possible explanation is that there were two such vessels. This is accountable by the fact that the days of the warbetween the states saw many Federal and Confederate boats changing names as well as affiliations. Official Union Naval records at Washington, D. C., show the Cairo as being built at St. Louis, under Captain James B. Eads and Company. She was officially known as an Eads gunboat, that famous group of vessels that made history on western waters. The Cairo was classified as a steamer, a wooden gunboat, rated like many of her companion vessels of the day as fourth class. Her tonnage is given as 512 and in January of 1862 she carried a battery of six 32-pounders; three 8 inch, 63 hundred weight; four army rifles, 80 hundred weight; and one 12-pounder howitzer. In September of that year she was listed as carrying the six 32-pounders , three army rifles, three 8 inch guns and one 30-pounder Parrot rifle. The Washington records show that the Cairo was sunk within less than five minutes after being struck by a torpedo, 18 miles up the Yazoo river, on December 12, 1862.