Simplyput, set it so that they may hold more than 70 units of ammo, and thus serve as a restocking facility.
Novas, mines, missles, any ammo a snubcraft would use. Allow them to store differnt ammounts of it based on their size and intention.
Ships like the vanilla house battleships and even Juggs, they double as light carriers, allow them to store enough for a few full resupplies (12ish maybe)
Actual carriers, Aquillion, Zephyr, Lib Carrier, Geb, allow them to store a lot more, with a ratio of size to comabt ability affecting what can be carried.