gdl is probably the most accurate way to achieve the curving tubular white object since it appears to have varying diameters (I can't even imagine where to begin - maybe
here? - it's a wild shot). The rest can be made using walls and profile manager. Unless you are already comfortable with gdl or willing to invest the time to code the tubular object I would probably stick to using profiles with the wall tool to achieve the curving object as a separate piece, save as .gsm, add "ROT" command to position it correctly (Yes, it won't be a true Nautilus shape - but maybe it doesn't have to be to serve its purpose?). Then build the the engine using the cylinder object (since it does not have to be detailed) and the metal feet/flaps/stands could also be achieved in profile manager with a wall.