Hint: the aliens acknowledge a solution to something that has to do with the big conflict. You could say it has something to do with storing stuff.
I think I responded too early last time so I'll wait longer in case someone finds the solution.

The International Load Line markings are found close to the center of the hull and indicate how far below the waterline a ship’s draft (the distance between the waterline and the bottom of the hull) may be governed by a variety of conditions, including fluctuations in water temperature and density.
Let us consider a large container ship that is being loaded while it is in port. The ship sinks further into the ocean as the weight and number of cargos increases. The ship would be at serious risk of sinking if the freeboard—the gap between the waterline and the top of the hull—became too small.
The following is a graphical representation of a typical load line marking.