Question: when were ironclads first used in the civil war
[{'answer': 'On 12 October 1861', 'provenance': [{'wikipedia_id': '251489', 'title': 'Ironclad warship', 'start_paragraph_id': 25, 'start_character': 0, 'end_paragraph_id': 25, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Early ironclad ships and battles.:First battles between ironclads: the U.S. Civil War.\n'}]}, {'provenance': [{'wikipedia_id': '251489', 'title': 'Ironclad warship', 'start_paragraph_id': 25, 'start_character': 0, 'end_paragraph_id': 25, 'end_character': 790, 'bleu_score': 0.8195643643924451, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5551712642901007853}, 'section': 'Section::::Early ironclad ships and battles.:First battles between ironclads: the U.S. Civil War.\n'}]}]