The overtaking maneuver of two Esso Bernicia 1.9×105 DWT tankers was investigated using the system-based maneuvering method. The Brix model was incorporated to account for the overtaking interactions. Forces/moment acting on the ship hulls and maneuvering motions were analyzed for both ships during the overtaking. The influences of the speed ratio and the passing distance were specially studied. Two fitting formulas for the minimum distance during the overtaking were finally established as functions of the two factors respectively. They can be used to predict the minimum distance during an overtaking maneuver under similar conditions to avoid marine accidents.