I always thought the people struggling in the water in this scene where 3rd class passengers who are desperately struggling to reach the Boat Deck. According to the James Cameron's Titanic Wiki
Solved In 1912, the RMS Titanic, a British passenger ship
What First, Second, and Third Class Passengers Aboard the Titanic Ate
RMS Titanic - World History Encyclopedia
The Ship of Dreams: The Sinking of by Russell, Mr. Gareth
First Class Entrance on RMS Empress of Ireland (Illustration) - World History Encyclopedia
File:B-21.jpg - Wikimedia Commons
Olympic & Titanic : Passenger Accommodation
Olympic & Titanic : Passenger Accommodation