Same trick is used on some external tanks for outboard engines: the tank has a raised separator in the bottom so that reserve fuel will be caught away from the

Same trick is used on some external tanks for outboard engines: the tank has a raised separator in the bottom so that reserve fuel will be caught away from the engine intake. To access the reserve fuel you need to briefly tilt the tank. See e.g. https://imgur.com/a/9LsrjIR https://imgur.com/a/9LsrjIR