 A more practical and influential weapon was the self @-@ propelled or Whitehead torpedo . <unk> in 1868 and deployed in the 1870s , the Whitehead torpedo formed part of the armament of ironclads of the 1880s like HMS <unk> and the Italian <unk> <unk> and Enrico <unk> . The ironclad 's vulnerability to the torpedo was a key part of the critique of armored warships made by the <unk> <unk> school of naval thought ; it appeared that any ship armored enough to prevent destruction by gunfire would be slow enough to be easily caught by torpedo . In practice , however , the <unk> <unk> was only briefly influential and the torpedo formed part of the confusing mixture of weapons possessed by ironclads . 
