Although there are numerous regulations provided for the Steering and Sailing Rules on the International Regulation forPreventing Collisions at Sea, 1972(hereinafter called COLREG), the most important Sailing Rules for approaching between two vessels in sight of one another could actually be defined as three typical aspects based on both the COLREG and practical sea experience. The Rules are overtaking , head-on situation and crossing situation applicable, those clearly prescribes on the COLREG. Thus, for easy understanding of these Rules comprehensive legal research is performed by every chapter in this paper so as to make practical implementation by duty officer of apprentice of shipping concerned. Consequently an aim of the study intends not only to exonerate any vessel, or the owner, master or crew there of, from consequences of well understanding and timely implementation to complying with the aforementioned three typical Steering and Sailing Rules which may be required by ordinary practice of seamen but also to avoid risk of collision at sea.