Check lists represent a very important tool within the International Safety Management Code, aimed at the regular and thorough assessment of the safety on board ships along with the operation of their parent companies. There seems to be only a few academic articles studying the communicative and rhetorical aspects of these maritime forms explaining why they are written in the way they are, especially in the light of their users who constitute a specific discourse community. The structure of a sample of representative lists is presented, as these check lists do not differ from the forms used by other European shipping companies. After interviews with the seafarers (deck and engine officers) to whom the check lists were administered, the conclusion was reached that they prefer short and unambiguous forms. In addition, a correlation about the language competence of the crew members on board ship was found: the simpler the discourse of the check list, the lower the responsibility of the crew member on board. Further, investigation into these complex language patterns focuses on the practical benefits.