Final answer:
Any sailing vessel, a vessel engaged in fishing, and a vessel less than 20 meters in length must not impede the passage of a larger vessel that can only navigate safely within a narrow channel.
Step-by-step explanation:
The vessel that is NOT to impede the passage of a vessel which can only navigate safely within a narrow channel is all of the above. According to maritime navigation rules, any sailing vessel, a vessel engaged in fishing, and a vessel that is less than 20 meters in length must not interfere with the safe passage of vessels that are constrained by their draft and can only navigate safely within a narrow channel. These vessels must take early and substantial action to avoid crossing the narrow channel or getting in the way of a vessel that must transit through the channel due to its size or draft.