Along with Vicksburg, the Army and the Navy were jointly besieging Port Hudson in Lousiana. These were the last Rebel strongholds on the Mississippi. Port Hudson was holding out in the belief that Johnson would come to Pemberton's aid at Vicksburg, thereby breaking Grant's siege. Pemberton and Johnson's troops would then march to break the siege at Port Hudson. Johnson did not, Vicksburg surrendered on July 4, 1863. Knowing all was lost, Port Hudson surrendered on July 9.
But in the days leading up to July 9, things got a little heated between the Union Army and the Union Navy. The commanding officer of the Army at Port Hudson, Major-General, N.P. Banks had an interesting exchange with the commanding officer, Captain Alden, of the flotilla assisting in the bombardment of Port Hudson. Will reproduce the exchange from the official records here, along with an interpretation of what the officers actually meant.
First message from Banks to Alden at 4:45 p.m. on June 26:
"I would request that the mortar firing from the fleet be stopped, as the shells are bursting in rear of our battery. [you are hitting your own side, stop it] The rifle guns of the fleet are doing excellent service, and it is desirable that their fire should continue. [great job when you hit the other guy, keep doing that]"
No response is provided from Alden.
At 6:30 p.m. the same day, Banks again sent a message to Alden:
"I would request that the firing from the fleet should be be continued after 7:30 p.m. to-night [ stop the bombardment because you can't be trusted not to hit us] on account of the workmen in the trenches, who will carry on their work against the citadel of the enemy during the night [ look we have our own job to do against the enemy and would appreciate you not killing us while we are doing it.]"
Banks responded at 3:30 in the morning on June 27:"Your two letters of to-night are received. I am glad to hear of the good results of our firing last evening, but regret to learn that our mortar shells were not more effective [sorry we hit you]. ... I have directed Commander Caldwell to enquire into the cause of their ineffective fire and to remedy it if possible [ We will try to do better, but there's only so much we can do]."
But the next day Banks had to send another message to Alden:
"The effect of the guns to-day was excellent and leaves us in no doubt at all that the citadel can be destroyed. [when you hit what you aim it, it's great]. ...The premature explosion of the shells endangered the lives of our men in the fort and in the trenches [Your little talk with Commander Caldwell achieved nothing]. This is greatly to be regretted [ I am getting pissed off ], because the fire of the mortars is most destructive to the enemy if the projectiles are well directed [ you are supposed to hit the enemy not us, you idiot]. I hope some means may be devised to make their fire effective and safe [ figure out how to aim the damn things, buddy]."
And thus ends the communication between the two for now.
Sources:Official Records of Union and Confederate Navies, volume 19, Operations: Western Gulf Bloackading Squadron