Of course being in high school, they are not alcoholic.
When they learn about Momo not getting into university, they offer to man the Mark IV they'd unknowingly been harboring to help her get in on a Sensha-do scholarship. Momo had saved them from being expelled in the past.
This includes their blatant disregard for their own tank (see Mundane Utility below), in amusing contrast with Yukari's devotion to them. Made apparent during their first encounter, with how the latter managed to top the challenges Shark Team threw at them.