Wow, the Hawaii Superferry is quite an amazing ship. It’s a massive catamaran style vessel that will Ferry people, cars, and trucks between the Islands of Oahu, Maui, and Kauai (I think that’s the initial route though there are some big environmental protests going on and court actions. Service is partially suspended pending environmental review).
National Geographic has a special about the building and testing of the ship, which attains a top speed of over 40 nautical miles per hour for the four hour trip from Hawaii to (Maui?).
Superferry Website for more information