 On 8 December 1863, "Signal" and defended disabled merchant steamer "Henry Von Phul", which had been shelled by a Southern shore battery.On 19 April 1864, "Signal" was ordered to ascend the Red River to Alexandria, Louisiana to protect coal and provision barges waiting there for the use of the flotilla of gunboats Rear Admiral David D. Porter had led farther upstream in the campaign known as the Red River Expedition.On 4 May, "Signal" was ordered "to take on board a bearer of dispatches from Mayor General Nathaniel Prentice Banks and proceed down the river..." About 20 miles down stream, the ship was fired upon by Confederate cavalrymen, and she returned the fire with her starboard guns.