Tolbi-bound Ship

The Tolbi-bound Ship (トレビ行きの船 Going-to-Trevi Ship) is the vessel that conveys Isaac and party across the Karagol Sea to Tolbi. A Boat Ticket can be purchased at the Kalay Docks, and at the docks is where the ship is anchored. However, the ships that have been sailing across the Karagol have been plagued by sea monsters as of late. Because of this, the captain will not set sail without his Anchor Charm. One of the crew men stole it and hid it atop the mast because he was scared to set sail, but Isaac and his friends recover this charm. After that, they, along with Sean and Ouranos volunteer to help fight off the monsters, much to the relief of the captain, his first mate Kaja, and the rest of the crew and passengers. The journey on the ship is fraught with monster attacks, with monsters taking out four of the ship's oarsmen. Isaac is tasked with selecting replacements from among the passengers, and the right combination can land the ship on Crossbone Isle. The battles on the ship culminate with a showdown with the Kraken. Sadly, the ship arrives too late for the Colosso hopefuls on board to enter the tournament.

Once the ship reaches the Tolbi Docks and you disembark, it is not possible to get back onto the ship. It is possible to find a hidden item inside a barrel in the captain's cabin. This should be picked up before leaving the ship.

Route to Crossbone Isle
There is a special way to make the ship go off course, however. After the first encounter with the sea monsters, Kaja will make you pick an oarsman to replace the one who has fallen to the Man o' Wars. Talk with the warrior in the green threads (He says: "Hey! You're not thinking of making me an oarsman, are you?"). Then after Kaja makes you pick another oarsman, pick the bald man (He says: "What? Ohhhh, noooo... Are you going to make me row?"). After that, pick the chef (He says: "You... You must be joking. You want me to row?"). Lastly, after finishing with the Kraken, pick the old man (He says: "Out of all these people, you're asking a frail old man like me to row?"). You'll know you did it right when the boat visibly goes northwest instead of just west after the Kraken battle. Kaja then says says he doesn't think the ship has been heading to Tolbi. They send you out to land on the uncharted area.

The above is actually one of eighteen available configurations of rowing passengers; another is to first use the bald man, then the blonde lady, then the purple merchant/tour guide, and finally the senile old man. Essentially, as Camelot Software Planning explained on their official Golden Sun website, the idea is to choose stronger passengers to be the oarsmen on the port (left) side and the weaker passengers to be the oarsmen on the starboard (right), to achieve enough of the imbalance that the ship veers off course.

In the game's internal code, each of the selectable rowers has a numerical value assigned to them. A list is as follows:
 * Old man=0
 * Blonde woman=3
 * Red-haired woman=4
 * Purple guide=5
 * Young man=6
 * Green guide=7
 * Cook=8
 * Bald man=9
 * Warrior=12

The sum of the two rowers on the right are compared to the sum of the two rowers on the left at the point the game decides whether to sail west to Tolbi Docks or northwest to Crossbone Isle. The ship will only veer to Crossbone Isle if the left sum is exactly 11 more than the right sum (it will not even work if the difference is more than 11, strangely enough). Based on the above list, only eighteen configurations of rowers will work.

On the area of world map you exit the ship out into, there is a large rock with an opening in the middle that you can enter. The dungeon-style area is the multi-floor dungeon Crossbone Isle, and while you can only get as far as into the fourth floor, you can get some good experience for the upcoming Colosso event in Tolbi and several good items, including stat-boosting items and the nicely strong Mystery Blade. Once you have hit the dead-end in the fourth floor that would require the Cloak Psynergy to pass, return to the ship, and the ship will make the remainder of its journey to Tolbi Docks uneventfully.

Collectibles
Since the Tolbi-bound Ship cannot be reentered after completing the crossing across Karagol Sea, the items below can be permanently missed:

23 Coins: In a barrel right in front of you as soon as you enter the passenger room. Anchor Charm: After you see the blue-capped crew member taking this item away from the captain's bridge, it will end up on top of the mast. Climb up it, get the charm, and give it to the boat captain following the necessary cutscenes to progress. Lucky Medal: In the lower right barrel of the storage room belowdecks. Nut: In the captain's bridge, this is in a white jar.