In a head-on situation between two PDVs, if one vessel is constrained by land on the starboard side and cannot alter to starboard, what action should be taken?

• A. Both vessels continue on their original courses
• B. The constrained vessel departs from the Rules and alters to port to stand well clear
• C. The other vessel should slow to avoid collision
• D. Both vessels reverse and stop

Answer: (B)

In a head-on encounter between power-driven vessels, the usual action is for each to alter course to starboard so they pass on the other’s port side. But if one vessel cannot turn to starboard because her starboard side is blocked by land, she cannot comply with that rule. In this situation, the safe course is for the constrained vessel to depart from the standard head-on maneuver and turn to port to stand well clear of the other vessel. This uses the only feasible maneuver to avoid collision given the obstruction, ensuring she does not force the other vessel into danger. The alternative of keeping both on their original courses, slowing only the other vessel, or reversing and stopping would not provide an effective or practical path to safety in this constrained scenario.