BOTH INTERNATIONAL & INLAND You are aboard vessel "A" which is towing on open waters when vessel "B", a sailing vessel, is sighted off your port bow as shown in illustration D020RR below. Which vessel is the stand-on?

Correct Answer: Option B — Vessel "B" is the stand-on vessel because it is sailing.

Rule 18(a)(iv) dictates that a power-driven vessel, even one engaged in towing, must keep out of the way of a sailing vessel. The sailing vessel is the stand-on vessel because it is not a power-driven vessel, and the towing vessel is the burdened vessel in this crossing situation.