Mobile is also prominent in some prison work songs. Old Alabama, a prison work song (as follows)

Old Alabama

Old Alabama, j'ines the state of Floridy
Old Alabama, j'ines the state of Floridy
At Mobile, Lawdy, at Mobile

Old Alabama, is a hog killing country (2x)
Ev'y fall, Lawdy, ev'y fall

Did you hear 'bout that water boy getting' drownded (2x)
In Mobile Bay, Lawdy, Mobile Bay

Did you hear 'bout the men all gonna leave you (3x)
Next pay day, Lawdy, next payday

Did you hear 'bout Louella Wallace (3x)
Poor gal dead, Lawdy, poor gal dead


I believe this is also related to the Manhaden shanty "Every Mail Day" in structure & content. Mobile was not only a just cotton port but also had a plantation economy, was quite a rail transportation spot & had a shipbuilding history. So as a song mart it had quite a few elements that would make it's name popular in song.

Barry