This might have been discussed previously – when your vessel is approaching a bend or an area of a channel or fairway, make sure you sound 1 PROLONGED BLAST since another vessel or vessels may not have a full view because of an intervening obstruction. If the your vessel is fitted with a WHISTLE at a distance apart of more than 100 meters, then 1 WHISTLE shall be used only for giving maneuvering and warning signals.

Remember International Rules and Inland Rules are DIFFERENT regarding MANEUVERING signals. Yes, they are both used to prevent collisions.

The International Rules apply to a POWER-DRIVEN vessel that going to make a maneuver while Inland Rules are signals of intent, where the other vessel must signal an agreement to the proposed maneuver.

Only with International Rules do you have specific sound signals that must be made when a vessel plans to overtake another in a narrow channel or fairway.

Yes, it is definitely confusing but that does not keep you from applying these applications!

Hugh Simpson