Stowaways on board of merchant marine's ships: from managing an event to the production of a risk. From being an inherent event related to maritime activities, the presence of a stowaway in merchant marine's ships progressively became a risk and a threat against what shipping companies have to protect themselves. Relevant of political and economic issues overstepping the maritime frame, this fantasied image of stowaways participates to the enhancement of security systems as well as it perfectly illustrates the transfer of migratory controls to the private sector, especially regarding insurance.