Farragut’s ships were all of wood; and, although steam in great part was the motive-power, sails were not superseded. Even as Farragut was concentrating in the Gulf, an event, to be described presently, took place in Hampton Roads which revolutionized naval warfare. But the enterprises in the Gulf were well started, and some triumphs still remained for the old-fashioned sailor and the old-fashioned ship.[223] In March the fleet managed to cross the bar and enter the Mississippi, a feat of no small difficulty in the case of the heavier vessels. The _Colorado_ was left outside, the _Pensacola_ was dragged by her consorts through a foot of mud, and the _Mississippi_ was scarcely less embarrassed. At last the squadron of attack was for the most part within the branches of the river; at the head of the passes they stripped like gladiators for a final struggle, and proceeded to attack the main obstructions twenty miles above. Farragut had seventeen ships for the attack, mounting one hundred and fifty guns, besides twenty mortar-schooners, with six attendant gunboats, under Commodore David D. Porter. Fort Jackson and Fort St. Philip, well manned and equipped, guarded the river on the west and east. An enormous chain, supported on anchored hulks, stretched across the half-mile of current to hold any approaching hostile vessels at a point where the fire of the forts could converge. Above the forts, a formidable flotilla of craft variously armed with rams and guns, some heaped with pitch-pine knots to serve as fire-ships, stood ready to take part.[224] [Illustration: FORTS OF THE MISSISSIPPI]