You have to loosen the rope attached to the tractor so that Oscar can drive away.
Zoom in on the winch at the back of the tractor. The rope is attached to it - try to turn the crank to the right with your mouse (it won't work). To unlock the crank, you have to use the wrench to turn the screw to the right with your mouse. When you do that, try to turn the crank again - this time with success.
If the two carts are still blocking the corner (left from Oscar in the truck), zoom in and disjoin them. Tell the automaton to move.
Now ask the Youkols standing at the broken fence (to the right from the place, where Oskar stopped) .
When they attatch the rope to the ferris wheel, go towards it - go through the gap in the fence (to the right from Oscar) and go further inside, so that you end up on the right side of the ferris wheel. Use the metal ladder to get to the control panel.
Powering up the ferris wheel
First, you've got to check the mechanism on the right. Zoom in and install another gear (the one taken from the Voralberg chest in the workshop) onto the big gear. Then pull the lever on the right. Zoom out and press the button on the panel (right side of it) that's located on the right from the ladder. When you manage to move Krystal (achievement: The Community of the Ostrich), go down the ladder and go back to the pier with tracks (from the ferris wheel inwards and when the camera shifts - to the right, and right again after the fence).
Enter the building through the door shown above - you will find yourself in the workshop; leave it on the other side.
Exit the park through the gate; go down the stairs and the right, where you will meet the Youkols waiting on the beach. Kurk will start talking. After the conversation go right pass a group of Youkols and proceed along the ship and next to the last remaining of the pier, go inwards.
After reaching the ship's stern, zoom in and click the lever to the left off the cargo hold entrance.