The Sin Ship is a 1931 American pre-Code drama film produced and distributed by RKO Radio Pictures and directed by the actor Louis Wolheim in his only directorial effort.

The screenplay was written by Hugh Herbert (who also acted in the film), from a story by Keene Thompson and Agnes Brand Leahy.

Cornered, they arrive at the San Francisco docks, where they convince the captain of a small cargo ship, Sam McVeigh, to take them aboard on his run to Mexico, mostly because he is enchanted with Kitty.

After the crew accuses McVeigh of the sabotage and tell him they plan to rape Kitty at the first opportunity, he goes to Marsden’s hotel room to enlist his help in protecting her.

"[5] Motion Picture Magazine described the film, "The first directorial effort of Louis Wolheim does not get off to a very auspicious start, but once the rat of melodrama is forced out into the open, a lively time is had by all.

"[6] The Motion Picture Herald, on the other hand, was more positive, stating the film had a "... meaningless title tacked onto a cracking good sea story", classing it as a "... very satisfactory entertainment for the smaller communities.

[3] Many of the harbor sequences were shot on Catalina Island, where LeBaron rented six speedboats to patrol the coastal waters and dampen the sound from sightseers and other onlookers.

[3] After completion of the film, Wolheim expressed his dissatisfaction with the role of directing, stating that from that point forward he only intended to act.