Penn's Landing in Philadelphia in Philadelphia County, Pennsylvania — The American Northeast (Mid-Atlantic)
Olympia's Guns & Turrets
On September 28, 1918, Olympia entered drydock at Charleston Navy Yard in Charleston, South Carolina for an extensive refit that included removing her 8"/35 guns and their protective turrets. These were replaced with open-mount gun platforms armed with 4"/40 guns.
In April 1917, Olympia was mobilized as the flagship of the U.S. Patrol Force, assigned to protect the eastern seaboard from the threat of German ships and submarines. In July she underwent another refit at New York Navy Yard where the gun platforms were widened to accommodate larger 5"/51 guns to better meet this new threat.
The turrets you see today are replicas.
Topics. This historical marker is listed in these topic lists: War, World I • Waterways & Vessels. A significant historical month for this entry is April 1917.
Location. 39° 56.63′ N, 75° 8.46′ W. Marker is in Philadelphia, Pennsylvania, in Philadelphia County. It is in Penn's Landing. It can be reached from South Christopher Columbus Boulevard south of Spruce Street, on the right when traveling north. Touch for map. Marker is at or near this postal address: 211 S Christopher Columbus Blvd, Philadelphia
this page online
Regionally, this marker is in Southeast Pennsylvania. It is also in the American Northeast and in the Mid-Atlantic. Globally, it is in North America, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it finds itself in what was once the Haudenosaunee (Iroquois) Confederacy, New Netherland, and one of the original Thirteen Colonies.
Other nearby markers. At least 8 other markers are within walking distance of this marker: A Visit from the President (here, next to this marker); The Casket of the American "Unknown Soldier" (here, next to this marker); U. S. S. Trigger - SS 237 (within shouting distance of this marker); Peace-Time Submariners Memorial (within shouting distance of this marker); Still on Patrol (within shouting distance of this marker); Local 8, Industrial Workers of the World (within shouting distance of this marker); Sphere / Esfera (within shouting distance of this marker); Five Spouts, Frog and Lintel (within shouting distance of this marker). Touch for a list and map of all markers in Philadelphia.
Another marker is
Photographed by Devry Becker Jones (CC0), December 12, 2025
4. Plaques on display inside the ship
Mechanical Engineering Landmark
Vertical Reciprocating Engines
U.S.S. Olympia
1892
This steam powered, steel hulled protected cruiser was one of the first naval ships built incorporating a lightweight, minimum height engine design.
Union Iron Works, San Francisco, CA - Builder
The American Society of Mechanical Engineers - 1977
has been designated a
National Historic Maritime Landmark
in recognition of her contribution to the science of naval design and construction on the occasion of the centennial anniversary of her sea trials
Society of Naval Architects and Marine Engineers
1993
Photographed by Devry Becker Jones (CC0), December 12, 2025
5. Signage by Independence Seaport Museum
Historic Ships
Climb aboard Olympia, the oldest floating steel warship in the world, and Becuna, a World War II-era submarine.
Climb aboard Olympia, the oldest floating steel warship in the world, and Becuna, a World War II-era submarine.
Credits. This page was last revised on December 14, 2025. It was originally submitted on December 14, 2025, by Devry Becker Jones of Washington, District of Columbia. This page has been viewed 65 times since then and 29 times this year. Photos: 1, 2, 3, 4, 5. submitted on December 14, 2025, by Devry Becker Jones of Washington, District of Columbia.
