The present concept of stress is related with the necessity of triangulation in research. Triangulation means collecting evidence of stress from at least three sources: (a) precursors--perception and feeling (moderating factors), (b) direct consequences, (c) state of health. Is it possible to implement triangulation in the investigations of work-related stress at sea? In the present paper, possibilities of collecting data on the work at sea are analyzed as regards individual aspects--stages of triangulation. The employment of triangulation principles to examine stress in persons working at sea requires both time and application of certain corrections to methodology of examinations carried out in Poland. When examining seafarers, we deal mainly with subjective information on perception of work and individual feeling of work-related stress. A proposition to expand the nethodological workshop of examining stress at sea according to triangulation principles has been presented.