The first stop is at the USS Cairo Museum in Vicksburg National Military Park, which was not one of the five gunboats, but it will give you an idea of their size.
The bayous and rivers were deeper back then (before levees) during spring flooding. The ironclad gunboats formed a single file line and couldn't turn around. General Sherman led a division along side them for support.
The plan was to gain control of the Mississippi and Yazoo rivers by isolating Vicksburg and outflanking Confederate batteries at Snyder's Bluff.
It is 30 miles up Steele Bayou to Black Bayou, 4 miles to Deer Creek, and then 30 miles to Rolling Fork Creek when you had to navigate to the Yazoo River by way of Big Sunflower River.
They gunboats got to Rolling Fork before having a fight with Confederates. Admiral D.D. Porter put the ships in reverse to escape. Confederates cut down trees in front of and behind the gunboats. Had the Confederate been able to capture the Union ships, that would have had quite an impact on operations in that area.
Damn the Snags and Mosquitoes. Full Speed Ahead. --B-R'er