From the very worn plaque, we found out the stack was from the USS Potomac.  This "false" stack held a hand powered elevator that FDR used while on board the Presidential Yacht.

When I emailed the Dorchester County Visitor Center, they told me:
"A local gentleman, Mr. Sam Brohawn, had the stack placed at its current location when the Potomac was refurbished in Cambridge for use by the State of Maryland."

She served as Presidential Yacht (1936 to 1944) and was owned by the State of MD from 1946 to 1960. She served as a ferry in the Caribbean; and was even owned, at one time, by Elvis Presley (1964).  Elvis gave the ship to Danny Thomas and the St Jude's Hospital auctioned the Potomac. After several owners she was seized in a drug raid and the US took over ownership. By this time the Potomac was in disrepair and everything of value had been removed.

FDR's greatest fear was being caught in a fire and being unable to escape.  He therefore preferred the U.S.S. Potomac, an all-steel vessel, to the all-wood Sequoia, the 100-ton ornate yacht used by his predecessor Herbert Hoover. FDR installed a hand-operated elevator inside a false stack, and the president - who had developed an extremely strong upper body - was able to use pulleys to move up and down between the saloon and upper boat deck. [http://usspotomac.org/html/body_history.htm]

An electric motor could have been installed but FDR used the elevator as a form of exercise. [http://home.rose.net/~dingdong/Yachts/Yachts2.html]

The final restoration cost of the ship was $5 million.  The money came from a government grant with matching funds from private sources (largely from efforts by FDR's son James and grandson Michael).

The Association for the Preservation of the Presidential Yacht Potomac now operates this National Historic Landmark as an active memorial to Franklin Delano Roosevelt, and the momentous times through which he led our nation.

Since 1995, the USS Potomac is open to the public at FDR Pier, Jack London Square, Oakland, CA.  It is fulfilling a two-fold mission: to honor one of America's greatest presidents during the Great Depression and World War II; and to provide a moving, tangible artifact of the FDR years for students and visitors from around the world.

According to the Potomac Association:
The FDR Pier...will be remodeled to better accommodate the physically challenged members of our society.

Now, I just have to figure when we will get to the west coast to visit the USS Potomac.  I will put it on on our ever growing "to do" list.  It was great to have seen a part of the old yacht...a part that meant so very much to a fellow polio survivor...FDR.

"FDR preferred travel by ship or train and made only one trip aboard the Sacred Cow, to attend a conference in Yalta, USSR with Churchill and Stalin. FDR traveled to Malta aboard the cruiser USS Quincy. From there on Feb. 3, 1945 FDR flew aboard the Sacred Cow to Saki (near Yalta). On Feb. 12, 1945 the Sacred Cow returned the President to the USS Quincy at Cairo, Egypt.

President Roosevelt never made a domestic flight. His final trip was by train to Warm Springs, Georgia and the same train returned his body to Washington DC and later to Hyde Park, New York."

First pool at the White House:  A heated indoor pool was installed for FDR in 1933 in the west wing.  It was covered over in 1969 and the press room was created by President Nixon.