Under International Rules, a vessel constrained by her draft must be which type of vessel?

• A. Power-Driven Vessel
• B. Sailing Vessel
• C. Not Under Command
• D. Not Restricted

Answer: (A)

A vessel constrained by her draft is a defined status in the International Rules (COLREGS). It means that because of her very deep draught relative to the available depth, she cannot deviate from her course to avoid another vessel. In practice, this limited ability to maneuver is treated as if she were a power-driven vessel for the purposes of determining which vessels must keep clear and how to apply the collision avoidance rules. The rigid constraint comes from the physical inability to turn or maneuver as freely as a lighter, more maneuverable vessel, so other vessels are expected to give way accordingly.

Think of a large tanker or heavy cargo ship moving through a shallow channel: its depth prevents quick steering changes, so it effectively behaves like a power-driven vessel in terms of risk and priority. This is why the correct classification for the purpose of the rules is power-driven, rather than sailing or one of the other RAM (not under command, restricted in ability to maneuver) categories, which are separate definitions with different implications.