Relieved from that command late in May, 1864, with leave to proceed home, he arrived at New Orleans in June, to find active preparations for the Mobile fight going on, and though he had not been at home for two years, he could not stand it to let slip so glorious an opportunity for stirring service, and so volunteered to remain. Farragut, delighted at such determination, quite different from the experience he had had with some officers, assigned to Perkins a command above his rank--the Chickasaw,--a double-turretted monitor, carrying four eleven-inch guns and a crew of one hundred and forty-five men and twenty-five officers. She had been built, together with the Winnebago, a sister vessel, at St. Louis, by Mr. Joseph B. Eads, the eminent engineer, on plans of his own. Of light draught and frame, and peculiar construction, some officers distrusted her strength and sea-going qualities. The Chickasaw, too, was not yet completed, the mechanics being still at work on her machinery and fittings, and her crew, with exception of a half-dozen men-of-war's-men, were river-men and landsmen, knowing nothing of salt-water sailing or of naval discipline. But time pressed: every moment was of priceless value; and Perkins, declining all social invitations, set about with characteristic energy to prepare his ship for the coming conflict. Nor did his work of preparation and drill cease, either in the river or outside, until well into the night preceding the eventful day in Mobile Bay that was to add another brilliant page to the annals of the navy. On the twenty-eighth of July, he left New Orleans to join the fleet off Mobile, and on the way down the river an episode occurred that came nigh settling the fate of the Chickasaw without risk or chance of battle; for on nearing the bar, Perkins left the pilot-house a moment to look after some matters requiring attention outside. He had hardly reached the spot he sought, when, turning round, he saw that the pilot had changed the ship's course and was heading directly for a wreck close aboard, which to strike would end the career of the Chickasaw then and there. Springing back into the pilot-house, he seized the wheel and brought the ship back on her course, then snatching a pistol from his belt, said to the traitorous fellow: "You are here to take this ship over the bar, and if she touches ground or anything else, I'll blow your d----d brains out!" Pale with suppressed rage, and trembling with fear, the pilot expostulated that "the bottom was lumpy, and the best pilot in the river could not help touching at times."