Sound signals: hear and learn them
A short blast lasts about one second, a prolonged blast four to six. All the sound signals vessels use to tell each other what they are doing are built from these two. Hear them here while you follow the pattern, then learn in the listening test whether you can recognise them unaided.
Manoeuvring and warning signals (Rule 34)
I am altering my course to starboard
I am altering my course to port
I am operating astern propulsion
Doubt and warning: I do not understand your intentions
Approaching a bend or an obscured stretch
I intend to overtake you on your starboard side
I intend to overtake you on your port side
Agreement to being overtaken
In restricted visibility, every two minutes (Rule 35)
Fog: power-driven vessel making way
Fog: power-driven vessel under way, not making way
Fog: sailing, fishing, restricted or towing vessel
Fog: manned vessel being towed
Listening test
Play the signal and tap what it means. Turn your sound on.
Short and long, and why it matters
Sound signals do not replace a manoeuvre, they announce it. A vessel altering to starboard gives one short blast so the other sees the move before things get tight. Five short blasts are the signal heard most often: I do not understand your intentions. If you get it, slow down at once and make your intention clear.
Simplified for learning. Inland waterways have their own signals under local rules.
