"The Great Steamboat Race," published in Uncle Scrooge #11 (Sept-Nov. 1955), is in my opinion one of Carl Barks' best stories. Which is saying a lot, since this is Carl Barks we're talking about.
What makes it great is how smoothly the various elements of the story--primarily the excitement of the race and the visual gags--all mesh together so perfectly. "The Great Steamboat Race" is a study in proper story construction for comic books.
The tale jumps off quickly with and argument between Scrooge McDuck and a guy (or rather an anthropomorphic pig) named "Horseshoe" Hogg. It seems that in 1870, their respective uncles had a steamboat race, with an ornate Southern mansion as the prize. But the boats both sank and the race was never finished. Hogg wants to do so, while Scrooge thinks its a waste of time and money.
Donald and the nephews sell Scrooge on the idea of being a Southern gentleman, so he finally agrees to the race. The idea is that the contestants will raise and repair the original steamboats (which have been sitting on the bottom of the Mississippi for 85 years), then finish the race from that point.
Hogg takes an extra-fast plane to the Mississippi and gets a jump on Scrooge. Also, Scrooge is reluctant to spend money on modern equipment to raise his steamboat.
What follows is a perfect mesh of adventure storytelling and comedy. The race is truly exciting, with the nephews coming up with a clever plan to quickly raise and repair Scrooge's steamboat on a strict budget. Scrooge's penny-pinching causes a setback at one point, but the old miser also shows he can also think on his feet when necessary.
At the same time, the gags--most of them centered around the moldy boat giving Scrooge sneezing fits--are truly funny. What tips the story over the edge into sheer brilliance is how the sneezing gags tie so seamlessly into the main plot. Scrooge's sneezes play a key role in winning the race. It also allows the story to come to a satisfying end with yet one more sneeze-based gag.
There's not a single wasted panel or a single moment that's doesn't tie into the primary plot. It's as if Barks took art, story and humor and performed a delicate operation to attach everything together so perfectly that you can't even see where the stitches are.