Capacity slots can each hold one "stack" of items, and each item has a set maximum number it can stack before it requires an additional slot. There are some "weightless" items, indicated by a feather icon in their slot, that do not contribute to capacity.
When the group is overburdened, each hex traveled costs an additional 10 Sanity. This penalty is the same no matter how many slots the group is overburdened with. This penalty is immediately removed when the player either throws away or consumes items equal to the number of slots overburdening the group.
Maximum capacity can be increased in several ways:
- Upgrading pack animals under Animal Improvement at port in London
- Keeping an animal handler as a companion along with animals.
- Selecting the Heavy Carrier explorer perk randomly offered after completing an expedition.
- Visiting a temple where a companion is randomly blessed with Inhuman Strength
- The Camp Site item can be exploited to work around overburdened capacity. Though the player must stop to rest often from the sanity-expensive travel legs, this allows the player to essentially carry limitless cargo in their inventory.
- Promoting companions does not increase their capacity, so make sure to choose party members that will adequately contribute to your maximum supply!