For a moment in April 1913 scandal at sea gripped the German courts, press, and parliament. An equator-crossing ceremony aboard the Nereide, a German merchant freighter bound for Chile, had turned violently sexual. Events aboard the ship placed the customs of maritime manhood on trial in full public view. The Nereide case illustrates how the performance of masculinity, sexuality, and violence shaped competing notions of belonging and difference at sea around 1900. Traditionally, the pain and humiliation of line-crossing rituals had signified a novice’s passage into the transnational community of deep-sea sailors. For scandalized Wilhelmine Germans, however, these rites seemed to threaten gendered categories of national belonging. Moreover, in the tense international atmosphere on the eve of World War I, sexual violence aboard a German merchant ship was not a simple criminal matter, but rather an embarrassment that tarnished Germany’s reputation as a leading maritime nation. In the light of public scrutiny, events aboard the Nereide emphasized mariners’ fundamental alterity, even as it provoked new calls to reform them into reliable German men.