Portuguese man o' war
The Atlantic Portuguese man o' war lives at the surface of the ocean. The gas-filled bladder, or pneumatophore, remains at the surface, while the remainder is submerged. As the Portuguese man o' war has no means of propulsion, they move according to the winds, currents, and tides. Although they are most commonly found in the open ocean in tropical and subtropical regions, they have been found as far north as the Bay of Fundy, Cape Breton and the Hebrides.
Man-of-war
The man-of-war (pl. men-of-war; also man of war, man-o'-war, man o' war, or simply man) was a British Royal Navy expression for a powerful warship or frigate from the 16th to the 19th century. The term often refers to a ship armed with cannons and propelled primarily by sails, as opposed to a galley which is propelled primarily by oars.