This paper deals with the automation techniques of ship assembly drawing generation, which help the designer to reduce the man-hour for completing the drawings, and improve the quality of the drawing for the given time. The automation techniques are necessary for the reasons of economical efficiency and improve communication between the designers and shop-makers. The overlap-avoidance algorithm of this paper maximizes the readability of the drawings using the optimization techniques and the heuristic rules, especially for the ship assembly field.