MS stands for Motor Ship, just as SS stands for Steam Ship, meaning the type of propulsion.
AK usually means Alaska in postal terms.
USS - United States Ship
Training Ship
The "S S" before a ship's name is an abbreviation for Steamship. It indicates that the ship is propelled by steam engines.
United States Ship
The initials RMS are associated with the Titanic and many other ships. They stand for Royal Mail Ship. A ship contracted to carry mail for the British Royal Mail can use these initials.
The M.S in a ships name usually designates it, as a "merchant ship " SS is sailing ship, HMAS is her majesty Australian ship, HMS, her majesty's ship. USS united states ship. etc However there are instances where the initials before a ship's Name identify it as belonging to a particular company
RMS in this context stands for Royal Mail Ship. Please see the related link.
This is what those terms stand for. SS stands for Steam Ship. USS stand for United State Ship. And HMS stands for His or Her Majesty's Ship.
The Mayflower was the name of the ship that the Pilgrims sailed on. The Ship, before the Pilgrims' Voyage, was used predominantly as a cargo ship.
RMS = Royal Merchant Ship.
RMS before a ship's name can stand for "Royal Mail Ship" "Royal Mail Steamer" or "Royal Mail Steamship" meaning the vessel was authorized to carry mail from port to port (see related link below)