BOTH INTERNATIONAL & INLAND You are approaching another vessel on crossing courses. She is approximately half a mile distant and is presently on your starboard bow. You believe she will cross ahead of you. She then sounds a whistle signal of five short blasts. You should __________.

Correct Answer: Option A — make a large course change, accompanied by the appropriate whistle signal, and slow down if necessary

Five short and rapid blasts represent the danger signal under COLREGS Rule 34(d), indicating doubt regarding intentions. The mariner must immediately take positive safety actions, including altering course and reducing speed to prevent a collision.