-  AGENCIES AND ORGANIZATIONS  -
Haze Gray & Underway
  http://www.hazegray.org/
Mariners
  http://www.mariners-l.co.uk/
Maritime Administration (MARAD)
    http://www.marad.dot.gov/index.htm
  PMARS Property Management and Archive Record System
    https://pmars.marad.dot.gov/
  MARAD Ship Disposal Program
    http://www.marad.dot.gov/ships_shipping_landing_page/ship_disposal_program/Ship_Disposal_Program.htm

Military Sealift Command (MSC)
      [
Formerly Military Sea Transportation Service (MSTS)]

  http://www.msc.navy.mil/
National Oceanic & Atmospheric Administration (NOAA)
  U.S. Department of Commerce
    http://www.noaa.gov/index.html
  NOAA Magazine
    http://www.magazine.noaa.gov/
  NOAA Ocean Explorer
    http://www.oceanexplorer.noaa.gov/
  NOAA History
    http://www.history.noaa.gov/index.html
  NOAA Central Library
    http://www.lib.noaa.gov/
Naval Historical Center
    http://www.history.navy.mil/index.html
  Ships History Branch
    http://www.history.navy.mil/branches/nhcorg9.htm
Naval Oceanography Portal,
United States Naval Meteorology and Oceanography Command (NMOC)
    http://www.usno.navy.mil/
Naval Oceanographic Office (NAVO)
    http://www.usno.navy.mil/NAVO
Naval Oceanographic Office (NAVOCEANO)
    https://oceanography.navy.mil/legacy/web/
  Major Shared Resource Center MSRC
    http://www.navo.hpc.mil/
  Matthew Fontaine Maury Oceanographic Library
    http://library.navo.navy.mil/
http://geniehost04.inmagic.com/InmagicGenie/opac.aspx/
Naval Research Laboratory
  http://www.nrl.navy.mil/
Naval Research Laboratory, Stennis Space Center
  http://www.nrl.navy.mil/content.php?P=STENNIS
Naval Vessel Register
  http://www.nvr.navy.mil/
NavSource Naval History (Photographic History Of The U.S. Navy)
  http://www.navsource.org/
Office of Naval Research
  http://www.onr.navy.mil/
Office of the Oceanographer and Navigator of the Navy
  http://www.oceanographer.navy.mil/
Scripps Institution of Oceanography
   http://sio.ucsd.edu/
United States Naval Observatory
  The James Melville Gilliss Library
    http://www.usno.navy.mil/USNO/library/library-home/?searchterm=Library
   
United States Navy (USN)
  http://www.navy.mil/
Universal Ship Cancellation Society
  http://www.uscs.org/
  NOTE:  Perhaps an unfortunate choice of names!  The Society does not actually cancel ships (I'm sure you're relieved), but promotes the study of the history of naval vessels, naval postal markings, and other postal documents involving the U.S. Navy.
U.S. Naval Institute
  http://www.usni.org/
Veterans History Project (The Library of Congress)
  http://www.loc.gov/vets/vets-home.html
Victory Ships
  http://www.usmm.org/victoryships.html
http://en.wikipedia.org/wiki/Victory_ship
Woods Hole Oceanographic Institute
  http://www.whoi.edu/
World Ship Society
  http://www.worldshipsociety.org/