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NavSource Online:
Lighthouse Tender Photo Archive

USED S. D. Mason (FS 551)
ex-USLHT Fern

Call sign (1924):
Nan - Able - Fox - Vice

Call sign (1942):
Nan - Roger - Peter - Vice

ex-USS Fern
ex-USLHT Fern

Fern served the U. S. Lighthouse Service, the U.S. Navy and the U.S. Army

Lighthouse Tender:

  • The third Fern was built in 1915 by Hall Brothers Shipbuilding Co., Winslow, WA for the Lighthouse Service
  • Commissioned USLHT Fern 25 June 1915 and based at Ketchikan, AK
  • Acquired by the Navy 4 September 1917 and placed in service the same day
  • Returned to the Lighthouse Service by Executive Order dated 1 July 1919
  • Decommissioned in 1934 and sold
  • Her new owner put her into service as a freight boat based at Seward, AK
  • Transferred to the Army 19 September 1934 and renamed USED S. D. Mason (FS 551)
  • Fate unknown.


  • Displacement 317 t.
    1917 - 237 t.
  • Length 112'
    1917 - 98' 5"
  • Beam 22'
  • Draft 10'
    1917 - 8' 6"
  • Complement 12
    1917 - 19
  • Armament: None
    1917 - Two 3-pounders
  • Propulsion: One water tube, oil fired Almy-type boiler; one triple-expansion vertical inverted steam engine; one shaft
    1934 - One 300hp diesel engine.

    Click on thumbnail
    for full size image
    Size Image Description Source
    USLHT Fern
    Fern 32k 28 June 1915
    Photo by L. F. Wheeler
    Smithsonian - National Museum of American History
    Photo added 26 February 2021
    USED S. D. Mason (FS-551)
    Fern 210k USED S. D. Mason (FS-551), tied up pierside, probably at Seattle, WA
    U.S. Army Corps of Engineers, Seattle District photo
    Photo from "U.S. Army Ships and Watercraft of World War II" by David H. Grover
    Robert Hurst

    View the Fern
    DANFS history entry located on the Naval History and Heritage Command website
    Back to the Main Photo Index Back to the Lighthouse Tender Photo Index Back to the Army Freight and Supply Vessel (FS) Photo Index

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    This page created by Joseph M. Radigan and maintained by David Wright
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