Claim: RMS Titanic was a ship.

Royal Mail Ship -LRB- sometimes Steam-ship or Steamer -RRB- is usually seen in its abbreviated form RMS , a designation which dates back to 1840 . It is the ship prefix used for seagoing vessels that carry mail under contract to the British Royal Mail . Any vessel designated as `` RMS '' has the right to fly both the pennant of the Royal Mail when sailing and to include the Royal Mail `` crown '' insignia with any identifying device and/or design for the ship .   It was used by many shipping lines , but is often associated in particular with the White Star Line , Cunard Line , Royal Mail Lines and Union-Castle Line , which held a number of high-profile mail contracts , and traditionally prefixed the names of many of their ships with the initials `` RMS '' .   While some lines in the past , particularly the Royal Mail Lines , called all their ships `` RMS '' , technically a ship would use the prefix only while contracted to carry mail , and would revert at other times to a standard designation such as `` SS '' .