Symbolism, Imagery, Allegory
Pippi grew up on the ocean—if you consider nine years old grown up, that is. Probably better to say that she's spent most of her life there, and when she leaves, it's quite an adjustment. As she tells the school teacher, "when you have sailed on the ocean your whole life, then you just don't know how to behave in school with all the apples and ibexes" (4.56). And when she's trying to figure out how to behave properly, she tells Annika and Tommy, "At sea we were never so fussy about things like that" (9.7).
Finally, after Mrs. Settergren has absolutely had it with Pippi's performance at the coffee party, Pippi says, "That's just what I was afraid of… That I couldn't behave properly. It's no use to try; I'll never learn. I should have stayed on the ocean" (9.49). Time and again, we see Pippi struggle to get her land legs after a childhood spent at sea.
Pippi's ocean is a lot like Huck Finn's river: a place where things are free and easy and where the standard rules of etiquette and society don't hold much sway. Makes you wonder what the coffee parties on her dad's ship looked like.