Hand written notes are on the original print, which is mounted on Hippocampus' "SP" data card, and reflect the compensation paid to the boat's owner for her use by the Navy during World War I.
History
United States
Name	USS Hippocampus
Namesake	name previously retained
Laid down	1912
Launched	1913 at New York City
Acquired	21 June 1917
Commissioned	25 June 1917
Decommissioned	November 1918
Stricken	1918
Homeport	Rockland, Maine
Identification	serial #31193
Fate	Returned to her owner on 5 April 1919
General characteristics
Type	yacht
Displacement	23 tons
Length	56-foot
Beam	11' 4"
Draft	2' 6"
Propulsion	gasoline engine
Speed	11 knots
Armament	one 11-pounder gun

USS Hippocampus (SP-654) was a yacht leased by the U.S. Navy during World War I. She was used as a patrol boat along the New England coast.

Hippocampus, a gasoline-powered yacht, was built by New York Yacht, Launch, & Engine Co. in 1912–1913 and was leased by the Navy from her owner, James F. Porter, of Chicago, Illinois, 21 June 1917. She was commissioned 25 June at Rockland, Maine.

Assigned to the 1st Naval District, Hippocampus served as a harbor patrol craft at the harbor entrance, Rockland, Maine, and in Penobscot Bay during World War I.

Post-war Hippocampus was decommissioned 30 November 1918 and returned to her owner 5 April 1919, who was paid $1847.85 for the use of his vessel ($500 for loss of use by the owner, and $1,347.85 for refurbishment to return the craft to its pre-war condition).

 This article incorporates text from the public domain Dictionary of American Naval Fighting Ships. The entry can be found here. The Hippocampus is currently owned by Capt. Ellic C. Mottram of Jonesport, ME. She is currently undergoing a full restoration to her original Yacht condition and is expected to be completed by 2016.

• Hippocampus (American Motor Boat, 1913).