USS Lydonia (SP-700)

USS Lydonia (SP-700) was a 497 gross ton yacht, Lydonia II, acquired from William A. Lydon by the U.S. Navy during World War I. She was outfitted as a patrol craft and spent most of the war based out of Gibraltar, escorting and protecting Allied ships in the Mediterranean and along the Atlantic Ocean coast of Europe. Post-war she was transferred to the U.S. Coast and Geodetic Survey as USCGS Lydonia (CS-302).

Construction
Lydonia II was the second yacht of the name built by Pusey and Jones, Wilmington, Delaware as hull #348 under contract #1205 for William A. Lydon, Commodore of the Chicago Yacht Club, and was more than 250 tons larger than the Lydonia I completed just two years earlier. The ship was designed by William A. Gardner with construction started in early April 1911 and launch on 25 July 1911. Fitting out took nine months with sea trial on 1 May 1912. She was described as "queen of the Great Lakes fleet" and "the finest on the Great Lakes."

World War I service
The ship was acquired by the Navy 21 August 1917 from William A. Lydon; and commissioned as USS Lydonia (SP-700) 27 October 1917, Lt. Cmdr, R. P. McCullough in command.

Based out of Gibraltar
After repairs and target practice off Bermuda, the converted yacht departed the Caribbean in mid November and arrived Horta, Azores, 7 December 1917. Two weeks later she arrived Gibraltar to join the U.S. patrol squadron operating along the Atlantic and Mediterranean sides of the Straits of Gibraltar. Assigned the task of protecting Mediterranean supply convoys, Lydonia remained on constant vigil for deadly U-boats during the early. months of 1918. She made two attacks on enemy submarines in February while guarding Allied convoys and although the results were negative. the experience was to pay off at a later date.

Encountering U-boat UB-70
On 8 May, Lydonia was steaming with a convoy from Bizerte to Gibraltar when she encountered German submarine UB-70. With the British destroyer Basilisk, the patrol craft made coordinated depth charge attacks at 1735, after the British merchant ship SS Ingleside was destroyed by a torpedo. After 15 minutes of running battle, the attack was curtailed and survivors of Ingleside were rescued. Heavy seas prevented an immediate assessment of possible damage to the submarine, but later evaluations credited Lydonia and Basilisk with sinking UB 70.

End-of-war operations
For the rest of the war, Lydonia continued escort operations from Bizerte to Gibraltar, playing a major role in the free movement of vital wartime supplies. Calling in Azores and Caribbean ports en route to the United States, she arrived Hampton Roads, Virginia, 6 February 1919.

Post-war disposal
Lydonia decommissioned at Norfolk, Virginia, 7 August 1919 and was transferred to the United States Coast and Geodetic Survey the same day.

United States Coast and Geodetic Survey service
Commissioned into the Coast and Geodetic Survey in 1919 as USC&GS Lydonia, Lydonia operated as a survey ship until 1947.