If you're talking about the large sail that blocks the door after you leave the Storage Room (see Steamworks Map), then all you do is walk up to it with the Mech on and the weed wacker attatchment, press the spacebar, and hit the bottom sail with the weed wacker.
That's all! Happy Adventuring!
you use the weed wacker
go on the roof and turn the wheel with your multi-tool.
its in the museum on mainstreet of steamworks island :)
It's Steamworks Island #14th Island
(The solution is at the related question "How do you beat Steamworks Island")
the crab on steamworks island is next to the living quarters
You go to Steamworks and head to the museum and there is the Deogen
pound it with the mech's weed whacker
steamworks island
There is a video walkthrough at the related link below. There are written WikiAnswers solutions at the related questions, as there are for all Poptropica islands. (How do you beat Steamworks Island) (What is the walkthrough for Steamworks Island)
Steamworks island
how to do the bridge terminal on poptropica's steamworks island