This is moreso a quality of life thing than anything that really needs to be implemented. I just find it tedious having to jump off the ship, grab resources in fives or tens if cannonballs, put it away, rinse and repeat. You're able to pick up a chest of gold with ease, I think picking up a barrel that only has 13 bananas should be just fine.
Pick up the barrel, go to where the resource is located, place barrel as if you were placing the individual resource into the cache. Hell it would even explain why you have these unused barrels throughout the ship.
