What does 1 short blast mean when boating?

1 blast means, I am turning to starboard (right)

2 blasts means, I am turning to port (left)

3 blasts means, I am going astern (backwards)

5 blasts means, I don't know what you are doing, get out of my way.....and usually accompanied by colourful language and waving of arms etc. Often heard around the commercial jetty when recreational boats get in the way of large commercial ferries etc...