A Lead in Grandship

Head to the tavern for a scene. After that, leave the tavern and head north to the next screen. Continue further north to reach the ship's Bridge. There's a hidden Zeus' Wrath in the gondola to the leftmost side of the bridge and a Turbo Ether under the large telescope. Leave the ship and travel back to Caldisla. Head to the inn and receive the orichalcum from Egil.

Return to the ship and head to the ship's bridge again and open the door. A new party chat will be available after the scene (Zatz's Name) Enter the engine room afterward.

Engine Room - B27

Follow the path the right then head south. Ignore the stairs to the southeast for now then continue to the left. Get the 1000pg from the chest in the middle and continue to the left. Upon reaching the stairs, open the chest to the north to get an Antarctic Wind. Go downstairs next.

B28

Go to the right to find a Turbo Ether. Make your way north and loot the chest to the northwest to get a Gold Hourglass. Follow the path southeast to reach another set of stairs. In the next floor, you should have access to a lever. Pull it down to operate the gears on the left side of the lift.

Backtrack all the way to B27's main area. From there, go back to the east and take the southeastern stairs.

B28

Head north and don't take the stairs yet. Grab the Cross Axe from the chest in the adjacent corridor and 2000pg from the chest to the northwest. Go downstairs afterward.

B29

There's a locked blue chest to the south of the stairs so take note of it for now. Continue south to find a chest containing a Trident. Backtrack to the northn then go left a bit. Enter the short corridor south and you'll find a Hammer Mace. Follow the main path to the west then south. Grab the Raikiri from the chest to the southwest and the Bacchus Wine from the chest in the dead end north of the southern stairs.

Once done, go upstairs to B28. Go straight up and take the stairs leading to B27 where the other lever is located. Pull it to fully activate the lift. Now backtrack to the main area and use the lift.

Engine Room Core

After getting off the lift, take the corridor to the left first to find a chest. Loot an Arctic Wind from it then take the other path. Go south then west. Halfway to the corridor lies a hidden path that leads to a Mega Elixir to the southwest. Continue along the western corridor to find a chest behind some overhead gears to the northwest. Get a Barrier Shroud from it. Return to the adventurer and save your game.

Before heading to the next boss battle, have your mages equip a White Cape or Silence Immunity support. If you can also have everybody wear Poison Immunity, that will do as well. Having a Salve-Maker as a job command will also help so you can use Widen Area to distribute healing and recovery items. If you have the Ninja job, it will help having that charater learn Utsusemi and Comeback Kid. For your physical attackers, it will help giving them BP Recovery from the Red Mage job class. This will allow them to recover 2BP when inflicted by a status ailment.

The next boss also deals physical damage so it will help boosting your party's P.Def rating. The boss is an Aquatic with weakness to Lightning so you can further increase your damage output by using the Ranger's Aquatic Killer or Sword Magic Thundara. When ready, head to the central platform and examine it.

Boss: Behemoth

HP:80,000 Weakness: Lightning, FAM: Aquatic

The boss has Roar that can cause silence to all characters. Your physical attackers don't need to be rid of this status ailment; however, if you have BP Recovery equipped on them, they'll recover much needed BP to be used for offense. You can heal them so if the boss uses Roar again and inflicts silence, they'll be recover BP again. You only need to protect your spellcasters by having silence immunity.

The Behemoth's Venomous Bite deals heavy damage and causes poison but that will help your characters with BP Recovery. Keep everyone healed up. A two-handed Swordmaster or Valkyrie or a Ninja with Ranger or sword magic job commands will be a tremendous help in dealing insane amounts of damage.

After the battle, watch the following scenes. You'll now have the oversized Grandship as your new airship. A new menu will be available in the lower screen as well. After the scene, new party chats will be available. (Ain't That the Truth, The Ice of Eternia)