Although some immigrants moved back to their home country, the flow of traffic from Europe to the Americas between 1850 and 1930 must've been very lopsided, and at the same time the liners advertised how comfortable their ships were, so I'm assuming they were not very good for hauling goods.
So what were they used for? Did they run empty? Could a poor person travel more comfortably if they decided to go back?
Cargoes shipped from the USA to Europe were usually bulky. Cotton, Lumber, Tobacco, Raw Wool, Corn, Wheat.
Cargoes shipped from Europe to the USA were more often manufactured goods.
The cargoes from Europe took up less space, so it made sense to try to use some of the ship for steerage passengers on the Europe to USA leg of the voyage.
(This applies mostly to the early packet ships like the Black Ball Line. Not sure how it worked when ships became more specialized to carry only passengers or only cargo.)
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