The first Zipline Part is found floating in a well, up the mountain from the docks. In order to get to the part, the player must align a number of hoses and funnels in order to pump water into the well, thereby increasing the water level. When the water level has risen enough, the player can simply pick the part through the hole in the grate covering the well.
The second part is found deep underwater, near to the Oxygen Pipe. Start at the bicycle-pump beneath the main Container Tower. There are air pockets in objects along the pipe that the player can use to refill their oxygen.
The third part can be found on a small island, after launching the rocket containing Major Tom, the astronaut. To launch this rocket, the player must provide an Explosive Powder. Many Poison Puffers are found around the island, so the player can obtain the Explosive Powder.