The cartoon was made in 1948 but not released until 1950. It features Bugs Bunny and Yosemite Sam as "Shanghai Sam". It is one of three nautical-themed shorts with Sam as a pirate, along with Buccaneer Bunny (1947) and Captain Hareblower (1954).
In 18th-century England, the triple-masted schooner the "Sad Sack" (formerly the "Jolly Roger") sits at the docks. The silence is broken when Yosemite Sam's former crew, a haggard, traumatized, disheveled man who looks half-insane, escapes (pausing only to say to the audience, "I was a human being once!"). "Shanghai Sam" is ready to sail at high tide and needs a new crew. Spying Bugs Bunny, Sam quickly signs him a fake deal for a free trip around the world. On board, Bugs waves goodbye to a cheering crowd and an Irish-speaking mouse ("He's not long for this world!"), and is knocked out when Sam conks him over the head.
Bugs finds himself rowing the ship's oars with an iron ball chained to his foot. He storms up to Sam and demands he get rid of it. Sam shrugs and chucks the iron ball, plus Bugs, overboard. Bugs storms up to Sam again (without the iron ball) and demands an explanation, but Sam orders Bugs to swab the deck. A short argument ends with Bugs mopping the deck. As payback, Bugs scrawls insults on the deck, which Sam angrily scrubs off. Bugs smugly compliments Sam on "keeping your ship so 'spic and span.'" Realizing he's been tricked, Sam points a pistol at Bugs. Bugs immediately tricks Sam to think that the ship is sinking: "Man the pumps! To the lifeboats! We're foundering fast!" Sam jumps into the lifeboat, but Bugs pulls him out and reminds him, "The Captain goes down with his ship." Sam instantly resigns and makes Bugs the captain. After an argument, he accepts; but when Sam gets back on the lifeboat, Bugs pulls him out again to remind him "Women and children first." Sam disguises himself as a hysterical old lady in need of rescuing. Bugs puts Sam in the lifeboat and drops it into the water. Just as Sam starts to row away, Bugs calls him back and throws him the ship's anchor dressed as a baby. The "baby" sinks Sam and his lifeboat.
Back on the ship, Sam discovers Bugs with some digging tools. When Bugs is asked what's he doing with them, he explains he's going to dig for buried treasure. This arouses Sam's interest, and he snatches the map. The clues on the map take Sam "10 paces Northeast from the mizzenmast, 27 steps down to the hold, and 5 paces to the right." When Sam comes upon the X, he starts chopping, only to break the hull and sink the Sad Sack.
Back at the docks, Sam hammers boards to the hole in the ship's hull. After launch, he takes a cannon and looks for Bugs, vengeance on his mind. He finds Bugs in the cargo hold. He aims the cannon into the hold and lights the fuse, only for Bugs to appear behind him. Panicking, Sam tries to blow out the fuse, but his actions only make it burn faster. The cannon fires into the hull, blasting a hole in it and sinking the Sad Sack again.
Back at the docks, Sam once again makes repairs. After launch, he takes a cannon and looks for Bugs again. He finds him up in the main mast. Sam aims the cannon upward, but when he fires a cannonball up to Bugs, the cannonball falls back and crashes down on Sam, pushing him through the hull. Underwater, a lump appears on Sam's head and the Sad Sack sinks on top of him.
Back at the docks, Sam again fixes his ship. This time, Bugs ties the ship to the slipway. During launch, the ship's exterior is ripped off, leaving only the frames and Sam to slide down the slipway and sink into the water. From the depths comes a white flag waving in surrender.
Much later Bugs and Sam are in a single rowboat, Bugs in a deck chair like a steamboat passenger, Sam rowing the boat for Bugs's trip around the world. Bugs exclaims about the places they've been and the things they've seen, and orders Sam to hurry so they can still make it to Rio de Janerio. The short irises out as they sail off into the sunset.
Second time in a Looney Tunes cartoon we see the star background and hear Columbia, the Gem of the Ocean in the background.
In this cartoon, Bugs gets fooled himself by the Reverse Psychology when he argues with Sam about swabbing the deck.
The messages Bugs wrote on the deck were "The Captain's wife wears army shoes" ("Oh, I'd like to lay my hands on the lily-livered slob that's writ that forgery!"), "The Captain loves Gravel Gertie" ("Oh, that dirty bilge rat has befouled my good name!"), and "The Captain is a shnook."
The footage and music where Sam rebuilds his ship on the docks is re-used twice (with the latter half [Sam putting boards over the hole] being reused once more before Bugs' final ploy), and the scene where is repaired ship is launched into the water is re-used once.
When Sam reads the clue "...and 5 paces to the right and dig at spot marked X" and follows the directions, he's actually going to his left, but the directions refer to the right side of the movie screen.