you are altering your course to starboard
it is the same right
three short blast
Passing on your starboard (right) side.
They are indicating dangerous
I intend to pass you on my starboard (right) side.
Means it's about to turn to port.
It is the "Masters Salute", a salute to the Master of another vessel.
1 short blast to pass on YOUR port side.
A boat is astern propulsion and is in the act of backing up
Three short blasts tell other boaters, “I am operating astern propulsion.” For some vessels, this tells other boaters, “I am backing up.”
A warning to other boaters there is danger near by.