Julie's uniform changes (from white with blue blouse to blue with red blouse) in consecutive scenes when passengers are embarking at the beginning, and again when passengers are disembarking at the end.
There are two evening scenes with the Edwards, the Loudens, Mr. Beatty and the crew, that are separated with day scenes. While it is conceivable that the Edwards (who are financially strapped) might wear the same outfit on two consecutive nights, Julie and Mrs. Louden certainly would not.
Sally Allison wouldn't have healed from a 3rd degree sunburn as quickly as she did.