What are the rules for internal collapsible fuel tanks in Traveller? These are fuel tanks designed to fit into a cargo hold and supply an extra boost to a starship's performance for when it needs to make a long range jump, and the crew don't care much about cutting into the cargo hold for an outward journey.
I've wanted to design a ship optimised for collapsible fuel tanks, and an overpowered power plant and J-drive for the ship's size. The sort of thing where, if they don't mind having very little space for cargo, they can fill the tanks with the fuel and make their long-range jump-4, -5 or -6 and take the long way round at jump-2 with cargo in the belly of their ship afterwards.
I can't seem to find the rules for collapsible and rigid cargo fuel pods anywhere in the new Traveller core book. What's the displaced mass of a collapsed (empty) collapsible fuel tank?