[alancalverd (OP)]

Cricket commentators have dragged their sport into the 21st century by replacing Batsman, Third Man and Twelfth Man by Batter, Third and Uniformed Reserve. It is therefore proposed that another ancient custom be revised in line with what is hoped to become common parlance:

If you see a someone disappear over the railings,

immediately shout "irrelevantly gendered anthropoid overboard"

nod in their general direction (pointing is discriminatory)

do not throw a lifeperson (it is prejudicial to suppose that they cannot swim)

seek consensus from the passengers and crew as to whether to execute a sharp turn around the point of disappearance (not everyone is popular with everyone else, and most passengers are in a hurry to get somewhere)

remember that a cry for help may be a Cry for Help, so as the vessel circles the victim, shout "How do you Feel?" and respect their answer. 

[Bored chemist]

do not throw a lifeperson (it is prejudicial to suppose that they cannot swim)

Or you could grow up and throw a lifebuoy.
It's not particularly prejudiced to assume they aren't as buoyant as they would like to be.