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Steamship Designations / Prefixes (Merchant Vessels)

The SS George Washington, Repaired at the Todd Shipyards Corporation.

The SS George Washington, Repaired at the Todd Shipyards Corporation. Shipping Magazine, 10 September 1921. GGA Image ID # 1d41b2fa6d

Prefixes are often used inconsistently and frequently not at all. Prefixes for a merchant marine vessel may identify the type of propulsion, such as "SS" for steamship, or purpose, such as "LB" for a lifeboat. Sometimes writers may use a slash to separate the letters, as in "M/S."

Ships during the late 1800s through 1950s all had a prefix. The most common prefixes appear below.

  • S.S. : Steamship (Steam Ship) This is the default designation
  • R.M.S. : Royal Mail Ship / Royal Mail Steamer
  • M.S. : Motor Ship or Mail Steamer
  • M.V. : Motor Vessel
  • R.M.M.V. : Royal Mail Motor Vessel
  • T.S.S. : Twin-Screw / Triple Screw Propulsion Ship
  • L.B. : Lifeboat

You will often see documents from the same voyage using different designations, such as SS Titanic and RMS Titanic. In this example, the RMS Titanic would have been carrying Royal Mail, so the RMS designated prefix. If the Titanic had made a return voyage, her designation would change to SS as she would not have been carrying any Royal Mail on departing from New York.

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The Folks Behind the GG Archives

The GG Archives is the work and passion of two people, Paul Gjenvick, a professional archivist, and Evelyne Gjenvick, a curator. Paul earned a Masters of Archival Studies - a terminal degree from Clayton State University in Georgia, where he studied under renowned archivist Richard Pearce-Moses. Our research into the RMS Laconia and SS Bergensfjord, the ships that brought two members of the Gjønvik family from Norway to the United States in the early 20th century, has helped us design our site for other genealogists. The extent of original materials at the GG Archives can be very beneficial when researching your family's migration from Europe.