Ferry
A system of ferries connects all colonized islands in the same archipelago. The ferries are available through the island's dock. Travelling via a ferry is instantaneous. At the present time, there is no fee to use a ferry.
A ferry becomes available as soon as any building or construction site is placed.
Historical notes
Ferries were introduced with Alpha release 2003-06-24. At that time, there was a small fee to use them. They were made free in Alpha release 2003-06-30. The charge returned with the global purse in release 2005-04-06, but it was quickly disabled, due to the whisk to home island option.
On Midnight, the ferry destinations are not always listed alphabetically. This appears to be an artifact of the colonization process. All the other oceans list the destinations in alphabetical order.