If two sailing vessels are running free with the wind on the same side, which vessel must keep clear?

Answer: B — The windward vessel

When two sailing vessels are on the same tack, the vessel that is to windward (upwind) must keep clear of the vessel to leeward (downwind). Being on the same tack means they’re both sailing with wind coming from the same side, so there isn’t a crossing maneuver to rely on; the safer arrangement is for the windward boat to yield. If the windward vessel doesn’t give way, there’s a higher risk of collision as the leeward vessel can’t easily maneuver out of the way without infringement of its own course. So, the windward vessel is the one that must keep clear. The other vessel has the right of way and can maintain its course. Speed or size isn’t the determining factor here; it’s the upwind/downwind relationship on the same tack that sets the obligation.