The day was a pleasant one for the launching, and despite the early hour set for the ceremony, Miss O’Brien, several of her relatives and friends, Lewis Nixon, Superintendent Ackerman, and the heads of the various departments were on hand. When the christening party were placed on the vessel the workmen released the huge hull and the _O’Brien_ gracefully slid from the ways. The launching of the _O’Brien_ marks another step in the consummation of the government plan of perpetuating the names of the more prominent figures in the American Revolution. The O’Briens were a family who possessed indomitable courage and spirit and played a conspicuous part in this country’s battle for freedom. It is stated that on the arrival of the _Margaretta_ off Machias, her commanding officer, Lieutenant Moore, notified the town officials that the Liberty pole must come down or the vessel would open fire on the town. On Sunday morning, May 11, a lumber sloop commanded by Jeremiah O’Brien, with about fifty men armed with muskets and pitchforks, left the town and sailed down the bay in the direction of the _Margaretta_. There was a hand-to-hand fight on the decks, and though the English fought well with their small arms, the _Margaretta_ was a prize within twenty minutes. Lieutenant Moore and ten of his men were killed and others severely wounded, the attacking party losing six men killed, while five were wounded. This capture was the first naval engagement of the American Revolution,[58] but Jeremiah O’Brien and his brothers, William and John, subsequently received provincial commissions and participated in other engagements as commanding officers. The _O’Brien_ is a magnificent boat and looks the fighter, every inch of her. She is 175 feet long on her water line, 17 feet beam, and of 14 feet, 6 inches draught. Her displacement is about 165 tons. Steel has been used whenever possible, and when wood has been used it has been electrically treated so as to be fireproof. In every part unnecessary weight has been eliminated. The piston rods, shafts, connecting rods and working parts generally are of nickel steel. There are four cylinder, triple expansion engines, one high power cylinder, 18 inches in diameter, one intermediate power cylinder, 27 inches in diameter, and two low power cylinders, 27½ inches in diameter, each with an 18‒inch stroke. The indicated horse power is 3,500, which will give 350 revolutions to the screws per minute. There are twin screws instead of a single screw. The propelling engines are located in a water-tight compartment.