Some fast ferries around the world do over 30 knots.
23 mph
How fast a boat can travel varies based on the type of boat. Some boats travel at very slow speeds like 3-4 knots, and others at 80+ knots.
8 knots on the good days.
about 15 miles an hour
I'm not sure what the maximum sped of a ferry is, but our BC ferries usually travel between 35km - 40km.
Most passenger jets fly at a speed of 400-500 knots.
About six miles per hour or 6.15 knots.
The 757's cruising speed ranges from 460 to 480 Knots
Most of the passenger river boat travels at 35 knots per hour.
34.75 knots
About 9.6 knots.
It depends on the airplane. i.e. a cessna needs around 70 knots while a Boeing 747 needs around 250 knots.