So the right side works and the left side doesn't? That is working correctly.
To have an oil rig fill a ship, you have to align everything correctly: 1) place waterway, 2) place ship pump on the water so that the waterway is highlighted, 3) place oil rig so it feeds the pump directly. (If you place the oil rig first, it might not be aligned to the rail grid properly.)
Guess we need another gallery picture for this :)