You are inside the big tanker. There's a ladder at the end of the corridors. There's also multiple levels down. In these hints the locations are referred like this: [-2 2]. This means level -2 and the second corridor from the right.
Unlike normal walkthroughs, in Nice Game Hints you can select just the puzzle you want hints for. Here are listed the puzzles for "In the tanker" in Encodya. The guide you choose only contains information about that puzzle, reducing possible spoilers for other puzzles.