Defeat the indicated pirate groups in the Item World to obtain the corresponding part.on floor 5, Innocent gate on floor 10). then, go down either route as normal.

Black Drill: Construction Pirates on Floors 31 and higher (does not appear on Turn 2).
Eryngi (Body): Artist Pirates on Floors 71 and higher on Item Growth Path.
Galleon III (Body): Sorry Pirates on Floors 41 and higher (first five floors only, x1 to x5).
Giant Turtle (Body): Fisherman Pirates on Floors 1 and higher.
Hunk House (Top): Warrior Pirates on Floors 61 and higher.
Metal Aft Propellor (Head): Red Pirates on Floors 81 and higher on Item Growth Path.
Mini-Yoshitsuna (Body): Robo Pirates or Masked Rangers while Reverse Pirating.
No.6 Locomotive (Body): Item Express Pirates on Floors 41 and higher on Innocent Boost Path (does not appear on Turn 2).
Old Wagon (Body): Farmer Pirates on Floors 1 and higher; or Food Stand Pirates on Floors 11 and higher.
P Flonzor X Body: Meowkins Pirates on Floors 91 and higher.
Prinny (Body): Prinny Pirates on Floors 71 and higher on Innocent Boost Path (does not appear on Turn 2).
Sharkpedo (Right): Duck Pirates on Floors 21 and higher (does not appear on Turn 2).
Skull: Gentle Ram (Head): Queen Pirates on Floors 81 and higher.
Starship Body G: Mech Pirates on Floors 61 and higher (does not appear on Turn 2).
Starship Stern G (Rear): Rotten Golem Pirates on Floors 51 and higher.
Torn-Up Mast: Ghost Pirates on Floors 31 and higher.
Training Wing (Left): Commando Pirates on Floors 51 and higher on Item Growth or Innocent Boost paths (does not appear on Turn 2). Note: On the first set of floors, take either gate on Floor 5 and then the other gate on Floor 10 (Item gate).
Treasure Ship (Body): Peachboy Pirates on Floors 51 and higher on Treasure Path (does not appear on Turn 2).