Depending on the size of the ship and the ships' engine, top speed varies. In general, you can expect top speed around 40 knots, and service speed (the speed that is most commonly used when passengers are onboard) is around 25-30 knots.
The average speed of a soccer ball when kicked by David Beckham is under 91 miles per hour. His top speed was recorded at 97 miles per hour while the top speed ever recorded was about 138 miles per hour.
The top speed of the super sport version is limited to 258mph. With the limiter removed it will do 267.8mph. The top speed of the original version is about 253mph. At top speed it gets about 3 miles per gallon, maybe less. : )