there has to be a few sexually frustrated crew members if they keep having all those sexual assaults on the cruise ships...
There was a slew of over five hundred credible complaints of sexual assualts on passengers by members of ship's crews that prompted an FBI investigation a few years ago, but they were confined to ONE cruise line that had a legacy of promoting the "anything goes" atmosphere of a typical "frat party" in which the crew, or at least the officers and staff, freely participated. The dynamic seems to have been a competition among junior male staff to "score" with the most beautiful women onboard, similar to that which might exist in some college fraternity houses, rather than sexual frustration.
The reputable major cruise lines have very strict policies about sexual behavior by officers, staff, and members of the crew -- if there's so much as a credible allegation, the former employee leaves the ship in the next port of call. The reputable lines have very strict policies prohibiting members of the crew from entering any passenger cabin unless their duties require them to do so, and equally strict policies prohibiting all employees from inviting passengers into crew, staff, and officer spaces aboard ship. Violations of these policies bring very strict penalties up to and including immediate dismissal.
BTW, modern cruise ships also have security cameras throughtout all public and shared crew spaces, so it would be nearly impossible for any of the ship's officers, staff, or member of the crew to get away with prohibited behavior. The camera in the respective passageway would show them entering a passenger's cabin or bringing a passenger "below decks," providing hard evidence to support an allegation of misconduct.