Cross over to the first large ship where a Ty-Foo will move back on forth, attempting to knock you off the ship. You also have to contend with an Octoomba and spiked roller, but the Green Star Ring demands you get through this area in order to claim Green Star #1 .
It’s easier if you use the GamePad to freeze the Ty-Foo and Ground Pound the Octoomba, then you only need to worry about the spiked roller. Climb up to the Warp Box to reach the next ship then turn around, walking the plank to a hidden 1-Up Mushroom . Continue ahead to a ? Block that contains a Mega Mushroom . Use this Power-Up to take out the Ty-Foos and Bullies as you make your way to the stern of the ship where another Warp Box is waiting.
Don’t use it yet, instead walk off to the right defeating the Octoomba so you can claim Green Star #2 . Now use the Warp Box and pop the ? Block to obtain a Mega Mushroom . Walk the planks leaping over to Green Star #3 then onto another boat where you can find two more Mega Mushrooms .
Defeat the Bullies to reveal the Warp Box that leads to the Goal Pole.