Captain's Rules of the Road Practice Test

In these signals, vessels communicate their intended maneuver to avoid a collision. A single short blast means I intend to pass you on your port side, while two short blasts mean I intend to pass you on your starboard side. When two power-driven vessels meet at a half-mile, the proper practice is to sound both signals in sequence: first one short blast, then two short blasts. This clearly conveys your passing side to the other vessel and helps coordinate safe passage. Using only one of those signals wouldn’t fully communicate the chosen side, and three short blasts indicate reversing engines, which isn’t the situation here.