Lyndonia (1920) photographed 27 March 1925 while owned by publisher Cyrus H.K. Curtis.  | 
| History | 
| Name | 
- Lyndonia
 
- Southern Seas (Pan American Airways)
 
- Southern Seas (US Army)
 
- USS Southern Seas (PY-32) (US Navy)
 
  | 
| Namesake | Curtis estate Lyndon, Wyncote, Pennsylvania | 
| Owner | Cyrus H.K. Curtis | 
| Builder | Consolidated Shipbuilding Company of Morris Heights, New York | 
| Launched | 1920 | 
| Homeport | Philadelphia, Pennsylvania (USCG #219815 registry) | 
| Fate | Sunk typhoon, Okinawa 9 October 1945 | 
| Notes | Purchased Pan American Airways 1940, U.S. Army 30 December 1941, acquired by U.S.N. 23 December 1942 | 
| General characteristics | 
| Type | Yacht | 
| Tonnage | 812 gt | 
| Length | 70.104 m (230.00 ft) LOA | 
| Beam | 9.144 m (30.00 ft) | 
| Draught | 3.84 m (12.6 ft) | 
| Depth | 5.67 m (18.6 ft) | 
| Decks | 3 | 
| Installed power | steam | 
| Propulsion | 4 boilers each with two oil burners & two triple expansion steam engines, replaced in 1925 with twin B&W 6 Cyl diesels | 
| Speed | 16 knots (30 km/h; 18 mph) | 
| Range | 6,000 at 12 | 
| Crew | 39, 6 guest staterooms | 
Lyndonia, built 1920, was the second steam-yacht bearing the name and the third yacht built for publisher Cyrus H.K. Curtis of the Curtis Publishing Company by the then Consolidated Shipbuilding Company of Morris Heights, New York. The name is taken from the historic name of his estate, Lyndon, in Wyncote, Pennsylvania.
After Curtis' death in 1933, the yacht was purchased by Pan American Airways, converted to a floating hotel for use in the south Pacific and renamed Southern Seas in a shuttle service from Nouméa to Australia. At the outbreak of World War II, the vessel was taken over by the U.S. Army for use as a passenger and cargo ship until grounded on a New Caledonian reef. The ship was salvaged by the U.S. Navy, repaired in New Zealand, commissioned 23 December 1942 as USS Southern Seas and designated as a Patrol Yacht (PY-32).