When you see names on a plaque or a wall and you dare to look into it the stories that unfold reveal our history in a very next door neighbor type of personal way.  The only connection up to this point in time (June 2009) to Hackensack Commander Williamson had with Hackensack is that of being married to a Mrs. Florence S. Beam of 341 Park Street Hackensack.  Apparently he had an impact on the city enough after being married to Mrs. Beam for 7 years to justify the people of the city of Hackensack  including his name on the plaque at the Library, City Hall and Hudson Street Cemetery.  I contacted the Naval War College Archivist Evelyn Cherpak to see if she could find some information on him and his family and this is the information she returned to me on 7/10/2009 explaining the families link to Naval history:

Dear Bob,
I found some interesting information on the three Williamsons:
William P. Williamson, his father Thomas (Thom) Williamson, and
Thomas’ father, William.

LCDR (Lieutenant Commander) William P. Williamson was born in
North Carolina on August 10, 1884.  He Graduated from the
U.S. Naval Academy in 1907, and died in an explosion on board USS Orisaba on August 17, 1918.  I checked the Dictionary of Naval Fighting Ships for the history of the USS Orisaba and there was no mention of the explosion.  The U. S. Naval Academy archives may have additional information on William.

William’s father Thomas (Thom) was born in 1833 in Edenton, NC on August 5, 1833.  He entered the U.S. Navy in 1853 as an assistant engineer.  In 1861 he was promoted to Chief Engineer.  At the outbreak of the Civil War, he chose to remain in the U. S. Navy while his father William P. Williamson joined the Confederate Navy as Engineer in Chief the Navy.  In 1906, Thomas was promoted to Rear Admiral on the retired list.  Thomas died on March 17, 1918.  His personal papers are at
Old Dominion University Norfolk, VA.

William P. Williamson, Thomas’s Father, was born in Virginia and was Chief Engineer of the U.S. Navy 1842-1861, before he joined the Confederate Navy.  He worked at the Gosport Navy Yard 1861-1862, and at the Richmond Station, 1862-1865.  He was involved in raising the USS Merrimack and converting her into the CSS Virginia (first Confederate ironclad ship to do battle with the USS Monitor March 8, 1862).  The records of the Confederate Navy have many references to William.

Hope this helps and clarifies things.

Regards,
Evelyn M. Cherpak PH.D.
Head, Naval Historical collection