This is the ship docked at Kalay Docks that is destined for Tolbi.
Once the tour group boards, you can give the ticketmaster your ticket and get on as well. First, approach the captain; a short cutscene will ensue. Then enter the passenger compartment and approach the bow of the ship for another one. After Sean and Ouranos say they will visit the Captain, follow them down to the Captain's quarters. Yet another cutscene will commence; the Captain is already to go when he realizes that his lucky charm, a small anchor, is missing. Before the conversation ends, one of the sailors will mention taking the charm. Use Mind Read to find where he hid it. Climb the mast and investigate the barrel at the top. Bring the Anchor to the Captain. He will at last agree to set sail, as long as your party agrees to protect the oarsmen, and if any of them should get hurt, that the other passengers will help row. Now, go down and see the oarsmen. One final Cutscene will take place, and then your journey will begin.
Almost immediately, the boat is attacked by 3 Man o' Wars. They incapacitate one oarsman before you fight them. They are quite easy to defeat, but now you'll have to pick a replacement from among the passengers. You can pick whomever you like, and several of them have funny complaints about it. After you've got a replacement, go back down the stairs with him (or her.) Once this is done, the ship starts moving again.
You don't get far before the next attack, however. Several Rabid Bats engage Ouranos and Sean, and while they are distracted, a Lizard Fighter and two more Rabid Bats sneak down below. Again, they injure an oarsman before you can defeat them, so go up and pick another. Same as before, the ship starts going once more.
Not surprisingly, the ship is raided a third time. Several Man o' Wars and a Virago are waiting for you below decks, and have hurt another oarsman. Another easy battle, and pick another Oarsman from the passengers. The ship takes off again.
Rinse and repeat a fourth time. The ship is attacked and you'll have to pick out another oarsman. This time, though, it's a much more dangerous foe.
Boss Battle: Kraken
As you come up from below, Sean and Ouranos are thrown aside like dolls. The Kraken then turns its sights on you. Use as many Djinn as possible against this beast. It's weak to fire, so let Garet take the lead on this. It's also strong against water, so let Mia hang back and heal. Zephyr and Granite are always good moves to use on the first turn, so have Isaac and Ivan concentrate on those. Once your strongest summons are available, don't hold back; give the Kraken the full force of their power. Ragnarok is always a powerful attack to use while waiting for Djinn to recover, as is Heat Wave.
After the battle, select the last oarsman replacement, and in a few minutes you'll finally land in Tolbi.