that made up his attacking fleet were of several distinct types, including some that had not even existed when the war began. Of the 18 vessels selected, eight were conventional wooden-hulled ships carrying large numbers of guns that fired broadside. Four of these had been with the West Gulf Blockading Squadron from the start (flagship , , , and ) and had fought in its battles on the Mississippi. Two smaller gunboats had likewise been with Farragut since the capture of New Orleans: and . was now very much like the others, but she had begun life as an experimental ironclad. Her armor had been found to be more hindrance than help, so it was removed. Three were double-enders (, , and ), a type of warship that had been developed during the war to navigate the tortuous channels of the interior rivers. Finally, four were representatives of the New Navy: ironclad monitors. Of these, and were improved versions of the original , featuring two large guns in a single turret. The and were twin-turreted river monitors of light draft; each mounted four guns that were smaller than those carried by the other two. Union Army Army cooperation was needed to take and hold the enemy forts. The commander of the Military Division of West Mississippi was Major General Edward Richard Sprigg Canby, a career soldier with whom Farragut worked in planning the attack on Mobile. He calculated that 5,000 soldiers could be taken from other responsibilities in the division, enough to effect a landing behind Fort Morgan and cut it off from communication with Mobile. Their plans were undercut, however, when General-in-Chief Ulysses S. Grant made an urgent call for troops to be sent to the Virginia theater, then entering its critical phase. Canby then believed that he could spare no more than 2,000, not enough to invest the largest fort but enough to take Dauphin Island and thereby secure contact between the fleet inside the bay and their support in the gulf. Canby and Farragut recognized that they would not be able to threaten Mobile, but possession of the lower bay would be of great enough use to the blockading fleet that the projected attack should not be canceled. Communication would be necessary between the fleet and the landing force, so Canby suggested that a contingent of his signal corpsmen be distributed among the major ships of Farragut's