Seagallop
Seagallop Ferries are a series of boats in Pokémon FireRed and LeafGreen which transport the player from Vermilion City to the Sevii Islands and back, as well as between the nine Sevii Islands. In addition, Seagallop ferries are the only means of accessing Navel Rock and Birth Island. They appear to use a mode of propulsion called "Hi-Speed" of which there are speed factors ranging from 1 to 9. Before boarding a Seagallop Ferry, a sailor will usually shout "All aboard Seagallop Hi-Speed..." followed by the speed the ferry will travel at.
Access to the Sevii Islands
After defeating Cinnabar's Gym, the player will receive a Tri-Pass from Bill, allowing the player to travel to and from Knot Island, Boon Island and Kin Island.
After defeating the Pokémon League, if the player visits Celio on Knot Island, he will ask for a Ruby and a Sapphire for his Network Machine. After the National Pokédex and Ruby are received, Celio takes the Tri-Pass and upgrades it to a Rainbow Pass, allowing access to all of the Sevii Islands so the player can find the Sapphire.